Merge pull request #7708 from SylvainCorlay/allow_none

allow_none=False for all trait types but Instance and Type

IPython/core/shellapp.py

@@ -1,432 +1,432 b''
 # encoding: utf-8
 """
 A mixin for :class:`~IPython.core.application.Application` classes that
 launch InteractiveShell instances, load extensions, etc.
 """
 
 # Copyright (c) IPython Development Team.
 # Distributed under the terms of the Modified BSD License.
 
 from __future__ import absolute_import
 from __future__ import print_function
 
 import glob
 import os
 import sys
 
 from IPython.config.application import boolean_flag
 from IPython.config.configurable import Configurable
 from IPython.config.loader import Config
 from IPython.core import pylabtools
 from IPython.utils import py3compat
 from IPython.utils.contexts import preserve_keys
 from IPython.utils.path import filefind
 from IPython.utils.traitlets import (
     Unicode, Instance, List, Bool, CaselessStrEnum
 )
 from IPython.lib.inputhook import guis
 
 #-----------------------------------------------------------------------------
 # Aliases and Flags
 #-----------------------------------------------------------------------------
 
 gui_keys = tuple(sorted([ key for key in guis if key is not None ]))
 
 backend_keys = sorted(pylabtools.backends.keys())
 backend_keys.insert(0, 'auto')
 
 shell_flags = {}
 
 addflag = lambda *args: shell_flags.update(boolean_flag(*args))
 addflag('autoindent', 'InteractiveShell.autoindent',
         'Turn on autoindenting.', 'Turn off autoindenting.'
 )
 addflag('automagic', 'InteractiveShell.automagic',
         """Turn on the auto calling of magic commands. Type %%magic at the
         IPython  prompt  for  more information.""",
         'Turn off the auto calling of magic commands.'
 )
 addflag('pdb', 'InteractiveShell.pdb',
     "Enable auto calling the pdb debugger after every exception.",
     "Disable auto calling the pdb debugger after every exception."
 )
 # pydb flag doesn't do any config, as core.debugger switches on import,
 # which is before parsing.  This just allows the flag to be passed.
 shell_flags.update(dict(
     pydb = ({},
         """Use the third party 'pydb' package as debugger, instead of pdb.
         Requires that pydb is installed."""
     )
 ))
 addflag('pprint', 'PlainTextFormatter.pprint',
     "Enable auto pretty printing of results.",
     "Disable auto pretty printing of results."
 )
 addflag('color-info', 'InteractiveShell.color_info',
     """IPython can display information about objects via a set of functions,
     and optionally can use colors for this, syntax highlighting
     source code and various other elements. This is on by default, but can cause
     problems with some pagers. If you see such problems, you can disable the
     colours.""",
     "Disable using colors for info related things."
 )
 addflag('deep-reload', 'InteractiveShell.deep_reload',
     """Enable deep (recursive) reloading by default. IPython can use the
     deep_reload module which reloads changes in modules recursively (it
     replaces the reload() function, so you don't need to change anything to
     use it). deep_reload() forces a full reload of modules whose code may
     have changed, which the default reload() function does not.  When
     deep_reload is off, IPython will use the normal reload(), but
     deep_reload will still be available as dreload(). This feature is off
     by default [which means that you have both normal reload() and
     dreload()].""",
     "Disable deep (recursive) reloading by default."
 )
 nosep_config = Config()
 nosep_config.InteractiveShell.separate_in = ''
 nosep_config.InteractiveShell.separate_out = ''
 nosep_config.InteractiveShell.separate_out2 = ''
 
 shell_flags['nosep']=(nosep_config, "Eliminate all spacing between prompts.")
 shell_flags['pylab'] = (
     {'InteractiveShellApp' : {'pylab' : 'auto'}},
     """Pre-load matplotlib and numpy for interactive use with
     the default matplotlib backend."""
 )
 shell_flags['matplotlib'] = (
     {'InteractiveShellApp' : {'matplotlib' : 'auto'}},
     """Configure matplotlib for interactive use with
     the default matplotlib backend."""
 )
 
 # it's possible we don't want short aliases for *all* of these:
 shell_aliases = dict(
     autocall='InteractiveShell.autocall',
     colors='InteractiveShell.colors',
     logfile='InteractiveShell.logfile',
     logappend='InteractiveShell.logappend',
     c='InteractiveShellApp.code_to_run',
     m='InteractiveShellApp.module_to_run',
     ext='InteractiveShellApp.extra_extension',
     gui='InteractiveShellApp.gui',
     pylab='InteractiveShellApp.pylab',
     matplotlib='InteractiveShellApp.matplotlib',
 )
 shell_aliases['cache-size'] = 'InteractiveShell.cache_size'
 
 #-----------------------------------------------------------------------------
 # Main classes and functions
 #-----------------------------------------------------------------------------
 
 class InteractiveShellApp(Configurable):
     """A Mixin for applications that start InteractiveShell instances.
     
     Provides configurables for loading extensions and executing files
     as part of configuring a Shell environment.
 
     The following methods should be called by the :meth:`initialize` method
     of the subclass:
 
       - :meth:`init_path`
       - :meth:`init_shell` (to be implemented by the subclass)
       - :meth:`init_gui_pylab`
       - :meth:`init_extensions`
       - :meth:`init_code`
     """
     extensions = List(Unicode, config=True,
         help="A list of dotted module names of IPython extensions to load."
     )
     extra_extension = Unicode('', config=True,
         help="dotted module name of an IPython extension to load."
     )
 
     reraise_ipython_extension_failures = Bool(
         False,
         config=True,
         help="Reraise exceptions encountered loading IPython extensions?",
     )
 
     # Extensions that are always loaded (not configurable)
     default_extensions = List(Unicode, [u'storemagic'], config=False)
     
     hide_initial_ns = Bool(True, config=True,
         help="""Should variables loaded at startup (by startup files, exec_lines, etc.)
         be hidden from tools like %who?"""
     )
 
     exec_files = List(Unicode, config=True,
         help="""List of files to run at IPython startup."""
     )
     exec_PYTHONSTARTUP = Bool(True, config=True,
         help="""Run the file referenced by the PYTHONSTARTUP environment
         variable at IPython startup."""
     )
     file_to_run = Unicode('', config=True,
         help="""A file to be run""")
 
     exec_lines = List(Unicode, config=True,
         help="""lines of code to run at IPython startup."""
     )
     code_to_run = Unicode('', config=True,
         help="Execute the given command string."
     )
     module_to_run = Unicode('', config=True,
         help="Run the module as a script."
     )
-    gui = CaselessStrEnum(gui_keys, config=True,
+    gui = CaselessStrEnum(gui_keys, config=True, allow_none=True,
         help="Enable GUI event loop integration with any of {0}.".format(gui_keys)
     )
-    matplotlib = CaselessStrEnum(backend_keys,
+    matplotlib = CaselessStrEnum(backend_keys, allow_none=True,
         config=True,
         help="""Configure matplotlib for interactive use with
         the default matplotlib backend."""
     )
-    pylab = CaselessStrEnum(backend_keys,
+    pylab = CaselessStrEnum(backend_keys, allow_none=True,
         config=True,
         help="""Pre-load matplotlib and numpy for interactive use,
         selecting a particular matplotlib backend and loop integration.
         """
     )
     pylab_import_all = Bool(True, config=True,
         help="""If true, IPython will populate the user namespace with numpy, pylab, etc.
         and an ``import *`` is done from numpy and pylab, when using pylab mode.
         
         When False, pylab mode should not import any names into the user namespace.
         """
     )
     shell = Instance('IPython.core.interactiveshell.InteractiveShellABC')
     
     user_ns = Instance(dict, args=None, allow_none=True)
     def _user_ns_changed(self, name, old, new):
         if self.shell is not None:
             self.shell.user_ns = new
             self.shell.init_user_ns()
 
     def init_path(self):
         """Add current working directory, '', to sys.path"""
         if sys.path[0] != '':
             sys.path.insert(0, '')
 
     def init_shell(self):
         raise NotImplementedError("Override in subclasses")
 
     def init_gui_pylab(self):
         """Enable GUI event loop integration, taking pylab into account."""
         enable = False
         shell = self.shell
         if self.pylab:
             enable = lambda key: shell.enable_pylab(key, import_all=self.pylab_import_all)
             key = self.pylab
         elif self.matplotlib:
             enable = shell.enable_matplotlib
             key = self.matplotlib
         elif self.gui:
             enable = shell.enable_gui
             key = self.gui
         
         if not enable:
             return
         
         try:
             r = enable(key)
         except ImportError:
             self.log.warn("Eventloop or matplotlib integration failed. Is matplotlib installed?")
             self.shell.showtraceback()
             return
         except Exception:
             self.log.warn("GUI event loop or pylab initialization failed")
             self.shell.showtraceback()
             return
             
         if isinstance(r, tuple):
             gui, backend = r[:2]
             self.log.info("Enabling GUI event loop integration, "
                       "eventloop=%s, matplotlib=%s", gui, backend)
             if key == "auto":
                 print("Using matplotlib backend: %s" % backend)
         else:
             gui = r
             self.log.info("Enabling GUI event loop integration, "
                       "eventloop=%s", gui)
 
     def init_extensions(self):
         """Load all IPython extensions in IPythonApp.extensions.
 
         This uses the :meth:`ExtensionManager.load_extensions` to load all
         the extensions listed in ``self.extensions``.
         """
         try:
             self.log.debug("Loading IPython extensions...")
             extensions = self.default_extensions + self.extensions
             if self.extra_extension:
                 extensions.append(self.extra_extension)
             for ext in extensions:
                 try:
                     self.log.info("Loading IPython extension: %s" % ext)
                     self.shell.extension_manager.load_extension(ext)
                 except:
                     if self.reraise_ipython_extension_failures:
                         raise
                     msg = ("Error in loading extension: {ext}\n"
                            "Check your config files in {location}".format(
                                ext=ext,
                                location=self.profile_dir.location
                            ))
                     self.log.warn(msg, exc_info=True)
         except:
             if self.reraise_ipython_extension_failures:
                 raise
             self.log.warn("Unknown error in loading extensions:", exc_info=True)
 
     def init_code(self):
         """run the pre-flight code, specified via exec_lines"""
         self._run_startup_files()
         self._run_exec_lines()
         self._run_exec_files()
         
         # Hide variables defined here from %who etc.
         if self.hide_initial_ns:
             self.shell.user_ns_hidden.update(self.shell.user_ns)
         
         # command-line execution (ipython -i script.py, ipython -m module)
         # should *not* be excluded from %whos
         self._run_cmd_line_code()
         self._run_module()
         
         # flush output, so itwon't be attached to the first cell
         sys.stdout.flush()
         sys.stderr.flush()
 
     def _run_exec_lines(self):
         """Run lines of code in IPythonApp.exec_lines in the user's namespace."""
         if not self.exec_lines:
             return
         try:
             self.log.debug("Running code from IPythonApp.exec_lines...")
             for line in self.exec_lines:
                 try:
                     self.log.info("Running code in user namespace: %s" %
                                   line)
                     self.shell.run_cell(line, store_history=False)
                 except:
                     self.log.warn("Error in executing line in user "
                                   "namespace: %s" % line)
                     self.shell.showtraceback()
         except:
             self.log.warn("Unknown error in handling IPythonApp.exec_lines:")
             self.shell.showtraceback()
 
     def _exec_file(self, fname, shell_futures=False):
         try:
             full_filename = filefind(fname, [u'.', self.ipython_dir])
         except IOError as e:
             self.log.warn("File not found: %r"%fname)
             return
         # Make sure that the running script gets a proper sys.argv as if it
         # were run from a system shell.
         save_argv = sys.argv
         sys.argv = [full_filename] + self.extra_args[1:]
         # protect sys.argv from potential unicode strings on Python 2:
         if not py3compat.PY3:
             sys.argv = [ py3compat.cast_bytes(a) for a in sys.argv ]
         try:
             if os.path.isfile(full_filename):
                 self.log.info("Running file in user namespace: %s" %
                               full_filename)
                 # Ensure that __file__ is always defined to match Python
                 # behavior.
                 with preserve_keys(self.shell.user_ns, '__file__'):
                     self.shell.user_ns['__file__'] = fname
                     if full_filename.endswith('.ipy'):
                         self.shell.safe_execfile_ipy(full_filename,
                                                      shell_futures=shell_futures)
                     else:
                         # default to python, even without extension
                         self.shell.safe_execfile(full_filename,
                                                  self.shell.user_ns,
                                                  shell_futures=shell_futures)
         finally:
             sys.argv = save_argv
 
     def _run_startup_files(self):
         """Run files from profile startup directory"""
         startup_dir = self.profile_dir.startup_dir
         startup_files = []
         
         if self.exec_PYTHONSTARTUP and os.environ.get('PYTHONSTARTUP', False) and \
                 not (self.file_to_run or self.code_to_run or self.module_to_run):
             python_startup = os.environ['PYTHONSTARTUP']
             self.log.debug("Running PYTHONSTARTUP file %s...", python_startup)
             try:
                 self._exec_file(python_startup)
             except:
                 self.log.warn("Unknown error in handling PYTHONSTARTUP file %s:", python_startup)
                 self.shell.showtraceback()
             finally:
                 # Many PYTHONSTARTUP files set up the readline completions,
                 # but this is often at odds with IPython's own completions.
                 # Do not allow PYTHONSTARTUP to set up readline.
                 if self.shell.has_readline:
                     self.shell.set_readline_completer()
         
         startup_files += glob.glob(os.path.join(startup_dir, '*.py'))
         startup_files += glob.glob(os.path.join(startup_dir, '*.ipy'))
         if not startup_files:
             return
         
         self.log.debug("Running startup files from %s...", startup_dir)
         try:
             for fname in sorted(startup_files):
                 self._exec_file(fname)
         except:
             self.log.warn("Unknown error in handling startup files:")
             self.shell.showtraceback()
 
     def _run_exec_files(self):
         """Run files from IPythonApp.exec_files"""
         if not self.exec_files:
             return
 
         self.log.debug("Running files in IPythonApp.exec_files...")
         try:
             for fname in self.exec_files:
                 self._exec_file(fname)
         except:
             self.log.warn("Unknown error in handling IPythonApp.exec_files:")
             self.shell.showtraceback()
 
     def _run_cmd_line_code(self):
         """Run code or file specified at the command-line"""
         if self.code_to_run:
             line = self.code_to_run
             try:
                 self.log.info("Running code given at command line (c=): %s" %
                               line)
                 self.shell.run_cell(line, store_history=False)
             except:
                 self.log.warn("Error in executing line in user namespace: %s" %
                               line)
                 self.shell.showtraceback()
 
         # Like Python itself, ignore the second if the first of these is present
         elif self.file_to_run:
             fname = self.file_to_run
             try:
                 self._exec_file(fname, shell_futures=True)
             except:
                 self.log.warn("Error in executing file in user namespace: %s" %
                               fname)
                 self.shell.showtraceback()
 
     def _run_module(self):
         """Run module specified at the command-line."""
         if self.module_to_run:
             # Make sure that the module gets a proper sys.argv as if it were
             # run using `python -m`.
             save_argv = sys.argv
             sys.argv = [sys.executable] + self.extra_args
             try:
                 self.shell.safe_run_module(self.module_to_run,
                                            self.shell.user_ns)
             finally:
                 sys.argv = save_argv

IPython/html/services/contents/manager.py

@@ -1,468 +1,468 b''
 """A base class for contents managers."""
 
 # Copyright (c) IPython Development Team.
 # Distributed under the terms of the Modified BSD License.
 
 from fnmatch import fnmatch
 import itertools
 import json
 import os
 import re
 
 from tornado.web import HTTPError
 
 from .checkpoints import Checkpoints
 from IPython.config.configurable import LoggingConfigurable
 from IPython.nbformat import sign, validate, ValidationError
 from IPython.nbformat.v4 import new_notebook
 from IPython.utils.importstring import import_item
 from IPython.utils.traitlets import (
     Any,
     Dict,
     Instance,
     List,
     TraitError,
     Type,
     Unicode,
 )
 from IPython.utils.py3compat import string_types
 
 copy_pat = re.compile(r'\-Copy\d*\.')
 
 
 class ContentsManager(LoggingConfigurable):
     """Base class for serving files and directories.
 
     This serves any text or binary file,
     as well as directories,
     with special handling for JSON notebook documents.
 
     Most APIs take a path argument,
     which is always an API-style unicode path,
     and always refers to a directory.
 
     - unicode, not url-escaped
     - '/'-separated
     - leading and trailing '/' will be stripped
     - if unspecified, path defaults to '',
       indicating the root path.
 
     """
 
     notary = Instance(sign.NotebookNotary)
     def _notary_default(self):
         return sign.NotebookNotary(parent=self)
 
     hide_globs = List(Unicode, [
             u'__pycache__', '*.pyc', '*.pyo',
             '.DS_Store', '*.so', '*.dylib', '*~',
         ], config=True, help="""
         Glob patterns to hide in file and directory listings.
     """)
 
     untitled_notebook = Unicode("Untitled", config=True,
         help="The base name used when creating untitled notebooks."
     )
 
     untitled_file = Unicode("untitled", config=True,
         help="The base name used when creating untitled files."
     )
 
     untitled_directory = Unicode("Untitled Folder", config=True,
         help="The base name used when creating untitled directories."
     )
 
     pre_save_hook = Any(None, config=True,
         help="""Python callable or importstring thereof
 
         To be called on a contents model prior to save.
 
         This can be used to process the structure,
         such as removing notebook outputs or other side effects that
         should not be saved.
 
         It will be called as (all arguments passed by keyword)::
 
             hook(path=path, model=model, contents_manager=self)
 
         - model: the model to be saved. Includes file contents.
           Modifying this dict will affect the file that is stored.
         - path: the API path of the save destination
         - contents_manager: this ContentsManager instance
         """
     )
     def _pre_save_hook_changed(self, name, old, new):
         if new and isinstance(new, string_types):
             self.pre_save_hook = import_item(self.pre_save_hook)
         elif new:
             if not callable(new):
                 raise TraitError("pre_save_hook must be callable")
 
     def run_pre_save_hook(self, model, path, **kwargs):
         """Run the pre-save hook if defined, and log errors"""
         if self.pre_save_hook:
             try:
                 self.log.debug("Running pre-save hook on %s", path)
                 self.pre_save_hook(model=model, path=path, contents_manager=self, **kwargs)
             except Exception:
                 self.log.error("Pre-save hook failed on %s", path, exc_info=True)
 
     checkpoints_class = Type(Checkpoints, config=True)
     checkpoints = Instance(Checkpoints, config=True)
-    checkpoints_kwargs = Dict(allow_none=False, config=True)
+    checkpoints_kwargs = Dict(config=True)
 
     def _checkpoints_default(self):
         return self.checkpoints_class(**self.checkpoints_kwargs)
 
     def _checkpoints_kwargs_default(self):
         return dict(
             parent=self,
             log=self.log,
         )
 
     # ContentsManager API part 1: methods that must be
     # implemented in subclasses.
 
     def dir_exists(self, path):
         """Does the API-style path (directory) actually exist?
 
         Like os.path.isdir
 
         Override this method in subclasses.
 
         Parameters
         ----------
         path : string
             The path to check
 
         Returns
         -------
         exists : bool
             Whether the path does indeed exist.
         """
         raise NotImplementedError
 
     def is_hidden(self, path):
         """Does the API style path correspond to a hidden directory or file?
 
         Parameters
         ----------
         path : string
             The path to check. This is an API path (`/` separated,
             relative to root dir).
 
         Returns
         -------
         hidden : bool
             Whether the path is hidden.
 
         """
         raise NotImplementedError
 
     def file_exists(self, path=''):
         """Does a file exist at the given path?
 
         Like os.path.isfile
 
         Override this method in subclasses.
 
         Parameters
         ----------
         name : string
             The name of the file you are checking.
         path : string
             The relative path to the file's directory (with '/' as separator)
 
         Returns
         -------
         exists : bool
             Whether the file exists.
         """
         raise NotImplementedError('must be implemented in a subclass')
 
     def exists(self, path):
         """Does a file or directory exist at the given path?
 
         Like os.path.exists
 
         Parameters
         ----------
         path : string
             The relative path to the file's directory (with '/' as separator)
 
         Returns
         -------
         exists : bool
             Whether the target exists.
         """
         return self.file_exists(path) or self.dir_exists(path)
 
     def get(self, path, content=True, type=None, format=None):
         """Get the model of a file or directory with or without content."""
         raise NotImplementedError('must be implemented in a subclass')
 
     def save(self, model, path):
         """Save the file or directory and return the model with no content.
 
         Save implementations should call self.run_pre_save_hook(model=model, path=path)
         prior to writing any data.
         """
         raise NotImplementedError('must be implemented in a subclass')
 
     def delete_file(self, path):
         """Delete file or directory by path."""
         raise NotImplementedError('must be implemented in a subclass')
 
     def rename_file(self, old_path, new_path):
         """Rename a file."""
         raise NotImplementedError('must be implemented in a subclass')
 
     # ContentsManager API part 2: methods that have useable default
     # implementations, but can be overridden in subclasses.
 
     def delete(self, path):
         """Delete a file/directory and any associated checkpoints."""
         self.delete_file(path)
         self.checkpoints.delete_all_checkpoints(path)
 
     def rename(self, old_path, new_path):
         """Rename a file and any checkpoints associated with that file."""
         self.rename_file(old_path, new_path)
         self.checkpoints.rename_all_checkpoints(old_path, new_path)
 
     def update(self, model, path):
         """Update the file's path
 
         For use in PATCH requests, to enable renaming a file without
         re-uploading its contents. Only used for renaming at the moment.
         """
         path = path.strip('/')
         new_path = model.get('path', path).strip('/')
         if path != new_path:
             self.rename(path, new_path)
         model = self.get(new_path, content=False)
         return model
 
     def info_string(self):
         return "Serving contents"
 
     def get_kernel_path(self, path, model=None):
         """Return the API path for the kernel
         
         KernelManagers can turn this value into a filesystem path,
         or ignore it altogether.
 
         The default value here will start kernels in the directory of the
         notebook server. FileContentsManager overrides this to use the
         directory containing the notebook.
         """
         return ''
 
     def increment_filename(self, filename, path='', insert=''):
         """Increment a filename until it is unique.
 
         Parameters
         ----------
         filename : unicode
             The name of a file, including extension
         path : unicode
             The API path of the target's directory
 
         Returns
         -------
         name : unicode
             A filename that is unique, based on the input filename.
         """
         path = path.strip('/')
         basename, ext = os.path.splitext(filename)
         for i in itertools.count():
             if i:
                 insert_i = '{}{}'.format(insert, i)
             else:
                 insert_i = ''
             name = u'{basename}{insert}{ext}'.format(basename=basename,
                 insert=insert_i, ext=ext)
             if not self.exists(u'{}/{}'.format(path, name)):
                 break
         return name
 
     def validate_notebook_model(self, model):
         """Add failed-validation message to model"""
         try:
             validate(model['content'])
         except ValidationError as e:
             model['message'] = u'Notebook Validation failed: {}:\n{}'.format(
                 e.message, json.dumps(e.instance, indent=1, default=lambda obj: '<UNKNOWN>'),
             )
         return model
     
     def new_untitled(self, path='', type='', ext=''):
         """Create a new untitled file or directory in path
         
         path must be a directory
         
         File extension can be specified.
         
         Use `new` to create files with a fully specified path (including filename).
         """
         path = path.strip('/')
         if not self.dir_exists(path):
             raise HTTPError(404, 'No such directory: %s' % path)
         
         model = {}
         if type:
             model['type'] = type
         
         if ext == '.ipynb':
             model.setdefault('type', 'notebook')
         else:
             model.setdefault('type', 'file')
         
         insert = ''
         if model['type'] == 'directory':
             untitled = self.untitled_directory
             insert = ' '
         elif model['type'] == 'notebook':
             untitled = self.untitled_notebook
             ext = '.ipynb'
         elif model['type'] == 'file':
             untitled = self.untitled_file
         else:
             raise HTTPError(400, "Unexpected model type: %r" % model['type'])
         
         name = self.increment_filename(untitled + ext, path, insert=insert)
         path = u'{0}/{1}'.format(path, name)
         return self.new(model, path)
     
     def new(self, model=None, path=''):
         """Create a new file or directory and return its model with no content.
         
         To create a new untitled entity in a directory, use `new_untitled`.
         """
         path = path.strip('/')
         if model is None:
             model = {}
         
         if path.endswith('.ipynb'):
             model.setdefault('type', 'notebook')
         else:
             model.setdefault('type', 'file')
         
         # no content, not a directory, so fill out new-file model
         if 'content' not in model and model['type'] != 'directory':
             if model['type'] == 'notebook':
                 model['content'] = new_notebook()
                 model['format'] = 'json'
             else:
                 model['content'] = ''
                 model['type'] = 'file'
                 model['format'] = 'text'
         
         model = self.save(model, path)
         return model
 
     def copy(self, from_path, to_path=None):
         """Copy an existing file and return its new model.
 
         If to_path not specified, it will be the parent directory of from_path.
         If to_path is a directory, filename will increment `from_path-Copy#.ext`.
 
         from_path must be a full path to a file.
         """
         path = from_path.strip('/')
         if to_path is not None:
             to_path = to_path.strip('/')
 
         if '/' in path:
             from_dir, from_name = path.rsplit('/', 1)
         else:
             from_dir = ''
             from_name = path
         
         model = self.get(path)
         model.pop('path', None)
         model.pop('name', None)
         if model['type'] == 'directory':
             raise HTTPError(400, "Can't copy directories")
         
         if to_path is None:
             to_path = from_dir
         if self.dir_exists(to_path):
             name = copy_pat.sub(u'.', from_name)
             to_name = self.increment_filename(name, to_path, insert='-Copy')
             to_path = u'{0}/{1}'.format(to_path, to_name)
         
         model = self.save(model, to_path)
         return model
 
     def log_info(self):
         self.log.info(self.info_string())
 
     def trust_notebook(self, path):
         """Explicitly trust a notebook
 
         Parameters
         ----------
         path : string
             The path of a notebook
         """
         model = self.get(path)
         nb = model['content']
         self.log.warn("Trusting notebook %s", path)
         self.notary.mark_cells(nb, True)
         self.save(model, path)
 
     def check_and_sign(self, nb, path=''):
         """Check for trusted cells, and sign the notebook.
 
         Called as a part of saving notebooks.
 
         Parameters
         ----------
         nb : dict
             The notebook dict
         path : string
             The notebook's path (for logging)
         """
         if self.notary.check_cells(nb):
             self.notary.sign(nb)
         else:
             self.log.warn("Saving untrusted notebook %s", path)
 
     def mark_trusted_cells(self, nb, path=''):
         """Mark cells as trusted if the notebook signature matches.
 
         Called as a part of loading notebooks.
 
         Parameters
         ----------
         nb : dict
             The notebook object (in current nbformat)
         path : string
             The notebook's path (for logging)
         """
         trusted = self.notary.check_signature(nb)
         if not trusted:
             self.log.warn("Notebook %s is not trusted", path)
         self.notary.mark_cells(nb, trusted)
 
     def should_list(self, name):
         """Should this file/directory name be displayed in a listing?"""
         return not any(fnmatch(name, glob) for glob in self.hide_globs)
 
     # Part 3: Checkpoints API
     def create_checkpoint(self, path):
         """Create a checkpoint."""
         return self.checkpoints.create_checkpoint(self, path)
 
     def restore_checkpoint(self, checkpoint_id, path):
         """
         Restore a checkpoint.
         """
         self.checkpoints.restore_checkpoint(self, checkpoint_id, path)
 
     def list_checkpoints(self, path):
         return self.checkpoints.list_checkpoints(path)
 
     def delete_checkpoint(self, checkpoint_id, path):
         return self.checkpoints.delete_checkpoint(checkpoint_id, path)

IPython/html/widgets/widget.py

@@ -1,489 +1,489 b''
 """Base Widget class.  Allows user to create widgets in the back-end that render
 in the IPython notebook front-end.
 """
 #-----------------------------------------------------------------------------
 # Copyright (c) 2013, the IPython Development Team.
 #
 # Distributed under the terms of the Modified BSD License.
 #
 # The full license is in the file COPYING.txt, distributed with this software.
 #-----------------------------------------------------------------------------
 
 #-----------------------------------------------------------------------------
 # Imports
 #-----------------------------------------------------------------------------
 from contextlib import contextmanager
 import collections
 
 from IPython.core.getipython import get_ipython
 from IPython.kernel.comm import Comm
 from IPython.config import LoggingConfigurable
 from IPython.utils.importstring import import_item
 from IPython.utils.traitlets import Unicode, Dict, Instance, Bool, List, \
     CaselessStrEnum, Tuple, CUnicode, Int, Set
 from IPython.utils.py3compat import string_types
 
 #-----------------------------------------------------------------------------
 # Classes
 #-----------------------------------------------------------------------------
 class CallbackDispatcher(LoggingConfigurable):
     """A structure for registering and running callbacks"""
     callbacks = List()
     
     def __call__(self, *args, **kwargs):
         """Call all of the registered callbacks."""
         value = None
         for callback in self.callbacks:
             try:
                 local_value = callback(*args, **kwargs)
             except Exception as e:
                 ip = get_ipython()
                 if ip is None:
                     self.log.warn("Exception in callback %s: %s", callback, e, exc_info=True)
                 else:
                     ip.showtraceback()
             else:
                 value = local_value if local_value is not None else value
         return value
 
     def register_callback(self, callback, remove=False):
         """(Un)Register a callback
 
         Parameters
         ----------
         callback: method handle
             Method to be registered or unregistered.
         remove=False: bool
             Whether to unregister the callback."""
         
         # (Un)Register the callback.
         if remove and callback in self.callbacks:
             self.callbacks.remove(callback)
         elif not remove and callback not in self.callbacks:
             self.callbacks.append(callback)
 
 def _show_traceback(method):
     """decorator for showing tracebacks in IPython"""
     def m(self, *args, **kwargs):
         try:
             return(method(self, *args, **kwargs))
         except Exception as e:
             ip = get_ipython()
             if ip is None:
                 self.log.warn("Exception in widget method %s: %s", method, e, exc_info=True)
             else:
                 ip.showtraceback()
     return m
 
 
 def register(key=None):
     """Returns a decorator registering a widget class in the widget registry. 
     If no key is provided, the class name is used as a key. A key is
     provided for each core IPython widget so that the frontend can use
     this key regardless of the language of the kernel"""
     def wrap(widget):
         l = key if key is not None else widget.__module__ + widget.__name__
         Widget.widget_types[l] = widget
         return widget
     return wrap
 
 
 class Widget(LoggingConfigurable):
     #-------------------------------------------------------------------------
     # Class attributes
     #-------------------------------------------------------------------------
     _widget_construction_callback = None
     widgets = {}
     widget_types = {}
 
     @staticmethod
     def on_widget_constructed(callback):
         """Registers a callback to be called when a widget is constructed.
 
         The callback must have the following signature:
         callback(widget)"""
         Widget._widget_construction_callback = callback
 
     @staticmethod
     def _call_widget_constructed(widget):
         """Static method, called when a widget is constructed."""
         if Widget._widget_construction_callback is not None and callable(Widget._widget_construction_callback):
             Widget._widget_construction_callback(widget)
 
     @staticmethod
     def handle_comm_opened(comm, msg):
         """Static method, called when a widget is constructed."""
         widget_class = import_item(msg['content']['data']['widget_class'])
         widget = widget_class(comm=comm)
 
 
     #-------------------------------------------------------------------------
     # Traits
     #-------------------------------------------------------------------------
     _model_module = Unicode(None, allow_none=True, help="""A requirejs module name
         in which to find _model_name. If empty, look in the global registry.""")
     _model_name = Unicode('WidgetModel', help="""Name of the backbone model 
         registered in the front-end to create and sync this widget with.""")
     _view_module = Unicode(help="""A requirejs module in which to find _view_name.
         If empty, look in the global registry.""", sync=True)
     _view_name = Unicode(None, allow_none=True, help="""Default view registered in the front-end
         to use to represent the widget.""", sync=True)
     comm = Instance('IPython.kernel.comm.Comm')
     
     msg_throttle = Int(3, sync=True, help="""Maximum number of msgs the 
         front-end can send before receiving an idle msg from the back-end.""")
     
     version = Int(0, sync=True, help="""Widget's version""")
     keys = List()
     def _keys_default(self):
         return [name for name in self.traits(sync=True)]
     
     _property_lock = Tuple((None, None))
     _send_state_lock = Int(0)
-    _states_to_send = Set(allow_none=False)
+    _states_to_send = Set()
     _display_callbacks = Instance(CallbackDispatcher, ())
     _msg_callbacks = Instance(CallbackDispatcher, ())
     
     #-------------------------------------------------------------------------
     # (Con/de)structor
     #-------------------------------------------------------------------------
     def __init__(self, **kwargs):
         """Public constructor"""
         self._model_id = kwargs.pop('model_id', None)
         super(Widget, self).__init__(**kwargs)
 
         Widget._call_widget_constructed(self)
         self.open()
 
     def __del__(self):
         """Object disposal"""
         self.close()
 
     #-------------------------------------------------------------------------
     # Properties
     #-------------------------------------------------------------------------
 
     def open(self):
         """Open a comm to the frontend if one isn't already open."""
         if self.comm is None:
             args = dict(target_name='ipython.widget',
                         data={'model_name': self._model_name,
                               'model_module': self._model_module})
             if self._model_id is not None:
                 args['comm_id'] = self._model_id
             self.comm = Comm(**args)
 
     def _comm_changed(self, name, new):
         """Called when the comm is changed."""
         if new is None:
             return
         self._model_id = self.model_id
         
         self.comm.on_msg(self._handle_msg)
         Widget.widgets[self.model_id] = self
         
         # first update
         self.send_state()
 
     @property
     def model_id(self):
         """Gets the model id of this widget.
 
         If a Comm doesn't exist yet, a Comm will be created automagically."""
         return self.comm.comm_id
 
     #-------------------------------------------------------------------------
     # Methods
     #-------------------------------------------------------------------------
 
     def close(self):
         """Close method.
 
         Closes the underlying comm.
         When the comm is closed, all of the widget views are automatically
         removed from the front-end."""
         if self.comm is not None:
             Widget.widgets.pop(self.model_id, None)
             self.comm.close()
             self.comm = None
     
     def send_state(self, key=None):
         """Sends the widget state, or a piece of it, to the front-end.
 
         Parameters
         ----------
         key : unicode, or iterable (optional)
             A single property's name or iterable of property names to sync with the front-end.
         """
         self._send({
             "method" : "update",
             "state"  : self.get_state(key=key)
         })
 
     def get_state(self, key=None):
         """Gets the widget state, or a piece of it.
 
         Parameters
         ----------
         key : unicode or iterable (optional)
             A single property's name or iterable of property names to get.
         """
         if key is None:
             keys = self.keys
         elif isinstance(key, string_types):
             keys = [key]
         elif isinstance(key, collections.Iterable):
             keys = key
         else:
             raise ValueError("key must be a string, an iterable of keys, or None")
         state = {}
         for k in keys:
             f = self.trait_metadata(k, 'to_json', self._trait_to_json)
             value = getattr(self, k)
             state[k] = f(value)
         return state
 
     def set_state(self, sync_data):
         """Called when a state is received from the front-end."""
         for name in self.keys:
             if name in sync_data:
                 json_value = sync_data[name]
                 from_json = self.trait_metadata(name, 'from_json', self._trait_from_json)
                 with self._lock_property(name, json_value):
                     setattr(self, name, from_json(json_value))
     
     def send(self, content):
         """Sends a custom msg to the widget model in the front-end.
 
         Parameters
         ----------
         content : dict
             Content of the message to send.
         """
         self._send({"method": "custom", "content": content})
 
     def on_msg(self, callback, remove=False):
         """(Un)Register a custom msg receive callback.
 
         Parameters
         ----------
         callback: callable
             callback will be passed two arguments when a message arrives::
             
                 callback(widget, content)
             
         remove: bool
             True if the callback should be unregistered."""
         self._msg_callbacks.register_callback(callback, remove=remove)
 
     def on_displayed(self, callback, remove=False):
         """(Un)Register a widget displayed callback.
 
         Parameters
         ----------
         callback: method handler
             Must have a signature of::
             
                 callback(widget, **kwargs)
             
             kwargs from display are passed through without modification.
         remove: bool
             True if the callback should be unregistered."""
         self._display_callbacks.register_callback(callback, remove=remove)
 
     #-------------------------------------------------------------------------
     # Support methods
     #-------------------------------------------------------------------------
     @contextmanager
     def _lock_property(self, key, value):
         """Lock a property-value pair.
 
         The value should be the JSON state of the property.
 
         NOTE: This, in addition to the single lock for all state changes, is 
         flawed.  In the future we may want to look into buffering state changes 
         back to the front-end."""
         self._property_lock = (key, value)
         try:
             yield
         finally:
             self._property_lock = (None, None)
 
     @contextmanager
     def hold_sync(self):
         """Hold syncing any state until the context manager is released"""
         # We increment a value so that this can be nested.  Syncing will happen when
         # all levels have been released.
         self._send_state_lock += 1
         try:
             yield
         finally:
             self._send_state_lock -=1
             if self._send_state_lock == 0:
                 self.send_state(self._states_to_send)
                 self._states_to_send.clear()
 
     def _should_send_property(self, key, value):
         """Check the property lock (property_lock)"""
         to_json = self.trait_metadata(key, 'to_json', self._trait_to_json)
         if (key == self._property_lock[0]
             and to_json(value) == self._property_lock[1]):
             return False
         elif self._send_state_lock > 0:
             self._states_to_send.add(key)
             return False
         else:
             return True
     
     # Event handlers
     @_show_traceback
     def _handle_msg(self, msg):
         """Called when a msg is received from the front-end"""
         data = msg['content']['data']
         method = data['method']
 
         # Handle backbone sync methods CREATE, PATCH, and UPDATE all in one.
         if method == 'backbone':
             if 'sync_data' in data:
                 sync_data = data['sync_data']
                 self.set_state(sync_data) # handles all methods
 
         # Handle a state request.
         elif method == 'request_state':
             self.send_state()
 
         # Handle a custom msg from the front-end.
         elif method == 'custom':
             if 'content' in data:
                 self._handle_custom_msg(data['content'])
 
         # Catch remainder.
         else:
             self.log.error('Unknown front-end to back-end widget msg with method "%s"' % method)
 
     def _handle_custom_msg(self, content):
         """Called when a custom msg is received."""
         self._msg_callbacks(self, content)
 
     def _notify_trait(self, name, old_value, new_value):
         """Called when a property has been changed."""
         # Trigger default traitlet callback machinery.  This allows any user
         # registered validation to be processed prior to allowing the widget
         # machinery to handle the state.
         LoggingConfigurable._notify_trait(self, name, old_value, new_value)
 
         # Send the state after the user registered callbacks for trait changes
         # have all fired (allows for user to validate values).
         if self.comm is not None and name in self.keys:
             # Make sure this isn't information that the front-end just sent us.
             if self._should_send_property(name, new_value):
                 # Send new state to front-end
                 self.send_state(key=name)
 
     def _handle_displayed(self, **kwargs):
         """Called when a view has been displayed for this widget instance"""
         self._display_callbacks(self, **kwargs)
 
     def _trait_to_json(self, x):
         """Convert a trait value to json
 
         Traverse lists/tuples and dicts and serialize their values as well.
         Replace any widgets with their model_id
         """
         if isinstance(x, dict):
             return {k: self._trait_to_json(v) for k, v in x.items()}
         elif isinstance(x, (list, tuple)):
             return [self._trait_to_json(v) for v in x]
         elif isinstance(x, Widget):
             return "IPY_MODEL_" + x.model_id
         else:
             return x # Value must be JSON-able
 
     def _trait_from_json(self, x):
         """Convert json values to objects
 
         Replace any strings representing valid model id values to Widget references.
         """
         if isinstance(x, dict):
             return {k: self._trait_from_json(v) for k, v in x.items()}
         elif isinstance(x, (list, tuple)):
             return [self._trait_from_json(v) for v in x]
         elif isinstance(x, string_types) and x.startswith('IPY_MODEL_') and x[10:] in Widget.widgets:
             # we want to support having child widgets at any level in a hierarchy
             # trusting that a widget UUID will not appear out in the wild
             return Widget.widgets[x[10:]]
         else:
             return x
 
     def _ipython_display_(self, **kwargs):
         """Called when `IPython.display.display` is called on the widget."""
         # Show view.
         if self._view_name is not None:
             self._send({"method": "display"})
             self._handle_displayed(**kwargs)
 
     def _send(self, msg):
         """Sends a message to the model in the front-end."""
         self.comm.send(msg)
 
 
 class DOMWidget(Widget):
     visible = Bool(True, allow_none=True, help="Whether the widget is visible.  False collapses the empty space, while None preserves the empty space.", sync=True)
     _css = Tuple(sync=True, help="CSS property list: (selector, key, value)")
     _dom_classes = Tuple(sync=True, help="DOM classes applied to widget.$el.")
     
     width = CUnicode(sync=True)
     height = CUnicode(sync=True)
     # A default padding of 2.5 px makes the widgets look nice when displayed inline.
     padding = CUnicode(sync=True)
     margin = CUnicode(sync=True)
 
     color = Unicode(sync=True)
     background_color = Unicode(sync=True)
     border_color = Unicode(sync=True)
 
     border_width = CUnicode(sync=True)
     border_radius = CUnicode(sync=True)
     border_style = CaselessStrEnum(values=[ # http://www.w3schools.com/cssref/pr_border-style.asp
         'none', 
         'hidden', 
         'dotted', 
         'dashed', 
         'solid', 
         'double', 
         'groove', 
         'ridge', 
         'inset', 
         'outset', 
         'initial', 
         'inherit', ''],
         default_value='', sync=True)
 
     font_style = CaselessStrEnum(values=[ # http://www.w3schools.com/cssref/pr_font_font-style.asp
         'normal', 
         'italic', 
         'oblique', 
         'initial', 
         'inherit', ''], 
         default_value='', sync=True)
     font_weight = CaselessStrEnum(values=[ # http://www.w3schools.com/cssref/pr_font_weight.asp
         'normal', 
         'bold', 
         'bolder', 
         'lighter',
         'initial', 
         'inherit', ''] + list(map(str, range(100,1000,100))),
         default_value='', sync=True)
     font_size = CUnicode(sync=True)
     font_family = Unicode(sync=True)
 
     def __init__(self, *pargs, **kwargs):
         super(DOMWidget, self).__init__(*pargs, **kwargs)
 
         def _validate_border(name, old, new):
             if new is not None and new != '':
                 if name != 'border_width' and not self.border_width:
                     self.border_width = 1
                 if name != 'border_style' and self.border_style == '':
                     self.border_style = 'solid'
         self.on_trait_change(_validate_border, ['border_width', 'border_style', 'border_color'])

IPython/html/widgets/widget_box.py

@@ -1,80 +1,80 b''
 """Box class.  
 
 Represents a container that can be used to group other widgets.
 """
 
 # Copyright (c) IPython Development Team.
 # Distributed under the terms of the Modified BSD License.
 
 from .widget import DOMWidget, register
 from IPython.utils.traitlets import Unicode, Tuple, TraitError, Int, CaselessStrEnum
 from IPython.utils.warn import DeprecatedClass
 
 @register('IPython.Box')
 class Box(DOMWidget):
     """Displays multiple widgets in a group."""
     _view_name = Unicode('BoxView', sync=True)
 
     # Child widgets in the container.
     # Using a tuple here to force reassignment to update the list.
     # When a proper notifying-list trait exists, that is what should be used here.
-    children = Tuple(sync=True, allow_none=False)
+    children = Tuple(sync=True)
     
     _overflow_values = ['visible', 'hidden', 'scroll', 'auto', 'initial', 'inherit', '']
     overflow_x = CaselessStrEnum(
         values=_overflow_values, 
-        default_value='', allow_none=False, sync=True, help="""Specifies what
+        default_value='', sync=True, help="""Specifies what
         happens to content that is too large for the rendered region.""")
     overflow_y = CaselessStrEnum(
         values=_overflow_values, 
-        default_value='', allow_none=False, sync=True, help="""Specifies what
+        default_value='', sync=True, help="""Specifies what
         happens to content that is too large for the rendered region.""")
 
     box_style = CaselessStrEnum(
         values=['success', 'info', 'warning', 'danger', ''], 
         default_value='', allow_none=True, sync=True, help="""Use a
         predefined styling for the box.""")
 
     def __init__(self, children = (), **kwargs):
         kwargs['children'] = children
         super(Box, self).__init__(**kwargs)
         self.on_displayed(Box._fire_children_displayed)
 
     def _fire_children_displayed(self):
         for child in self.children:
             child._handle_displayed()
 
 
 @register('IPython.FlexBox')
 class FlexBox(Box):
     """Displays multiple widgets using the flexible box model."""
     _view_name = Unicode('FlexBoxView', sync=True)
     orientation = CaselessStrEnum(values=['vertical', 'horizontal'], default_value='vertical', sync=True)
     flex = Int(0, sync=True, help="""Specify the flexible-ness of the model.""")
     def _flex_changed(self, name, old, new):
         new = min(max(0, new), 2)
         if self.flex != new:
             self.flex = new
 
     _locations = ['start', 'center', 'end', 'baseline', 'stretch']
     pack = CaselessStrEnum(
         values=_locations, 
-        default_value='start', allow_none=False, sync=True)
+        default_value='start', sync=True)
     align = CaselessStrEnum(
         values=_locations, 
-        default_value='start', allow_none=False, sync=True)
+        default_value='start', sync=True)
 
 
 def VBox(*pargs, **kwargs):
     """Displays multiple widgets vertically using the flexible box model."""
     kwargs['orientation'] = 'vertical'
     return FlexBox(*pargs, **kwargs)
 
 def HBox(*pargs, **kwargs):
     """Displays multiple widgets horizontally using the flexible box model."""
     kwargs['orientation'] = 'horizontal'
     return FlexBox(*pargs, **kwargs)
 
 
 # Remove in IPython 4.0
 ContainerWidget = DeprecatedClass(Box, 'ContainerWidget')

IPython/html/widgets/widget_float.py

@@ -1,298 +1,296 b''
 """Float class.  
 
 Represents an unbounded float using a widget.
 """
 #-----------------------------------------------------------------------------
 # Copyright (c) 2013, the IPython Development Team.
 #
 # Distributed under the terms of the Modified BSD License.
 #
 # The full license is in the file COPYING.txt, distributed with this software.
 #-----------------------------------------------------------------------------
 
 #-----------------------------------------------------------------------------
 # Imports
 #-----------------------------------------------------------------------------
 from .widget import DOMWidget, register
 from IPython.utils.traitlets import Unicode, CFloat, Bool, CaselessStrEnum, Tuple
 from IPython.utils.warn import DeprecatedClass
 
 #-----------------------------------------------------------------------------
 # Classes
 #-----------------------------------------------------------------------------
 class _Float(DOMWidget):
     value = CFloat(0.0, help="Float value", sync=True)
     disabled = Bool(False, help="Enable or disable user changes", sync=True)
     description = Unicode(help="Description of the value this widget represents", sync=True)
 
     def __init__(self, value=None, **kwargs):
         if value is not None:
             kwargs['value'] = value
         super(_Float, self).__init__(**kwargs)
 
 class _BoundedFloat(_Float):
     max = CFloat(100.0, help="Max value", sync=True)
     min = CFloat(0.0, help="Min value", sync=True)
     step = CFloat(0.1, help="Minimum step that the value can take (ignored by some views)", sync=True)
 
     def __init__(self, *pargs, **kwargs):
         """Constructor"""
         super(_BoundedFloat, self).__init__(*pargs, **kwargs)
         self._handle_value_changed('value', None, self.value)
         self._handle_max_changed('max', None, self.max)
         self._handle_min_changed('min', None, self.min)
         self.on_trait_change(self._handle_value_changed, 'value')
         self.on_trait_change(self._handle_max_changed, 'max')
         self.on_trait_change(self._handle_min_changed, 'min')
 
     def _handle_value_changed(self, name, old, new):
         """Validate value."""
         if self.min > new or new > self.max:
             self.value = min(max(new, self.min), self.max)
 
     def _handle_max_changed(self, name, old, new):
         """Make sure the min is always <= the max."""
         if new < self.min:
             raise ValueError("setting max < min")
         if new < self.value:
             self.value = new
 
     def _handle_min_changed(self, name, old, new):
         """Make sure the max is always >= the min."""
         if new > self.max:
             raise ValueError("setting min > max")
         if new > self.value:
             self.value = new
 
 
 @register('IPython.FloatText')
 class FloatText(_Float):
     """ Displays a float value within a textbox. For a textbox in
 	which the value must be within a specific range, use BoundedFloatText.
 
 	Parameters
 	----------
 	value : float
 	    value displayed
 	description : str
 	    description displayed next to the textbox   
 	color : str Unicode color code (eg. '#C13535'), optional
 	    color of the value displayed   
     """
     _view_name = Unicode('FloatTextView', sync=True)
 
 
 @register('IPython.BoundedFloatText')
 class BoundedFloatText(_BoundedFloat):
     """ Displays a float value within a textbox. Value must be within the range specified.
 	For a textbox in which the value doesn't need to be within a specific range, use FloatText.
 
 	Parameters
 	----------
 	value : float
 	    value displayed
 	min : float
 	    minimal value of the range of possible values displayed
 	max : float
 	    maximal value of the range of possible values displayed
 	description : str
 	    description displayed next to the textbox  
 	color : str Unicode color code (eg. '#C13535'), optional
 	    color of the value displayed   
     """
     _view_name = Unicode('FloatTextView', sync=True)
 
 
 @register('IPython.FloatSlider')
 class FloatSlider(_BoundedFloat):
     """ Slider/trackbar of floating values with the specified range.
 
 	Parameters
 	----------
 	value : float
 	    position of the slider
 	min : float
 	    minimal position of the slider
 	max : float
 	    maximal position of the slider
 	step : float
 	    step of the trackbar
 	description : str
 	    name of the slider
 	orientation : {'vertical', 'horizontal}, optional
             default is horizontal
 	readout : {True, False}, optional
 	    default is True, display the current value of the slider next to it		
 	slider_color : str Unicode color code (eg. '#C13535'), optional 
 	    color of the slider 
 	color : str Unicode color code (eg. '#C13535'), optional
 	    color of the value displayed (if readout == True)
     """
     _view_name = Unicode('FloatSliderView', sync=True)
     orientation = CaselessStrEnum(values=['horizontal', 'vertical'], 
-        default_value='horizontal', 
-        help="Vertical or horizontal.", allow_none=False, sync=True)
+        default_value='horizontal', help="Vertical or horizontal.", sync=True)
     _range = Bool(False, help="Display a range selector", sync=True)
     readout = Bool(True, help="Display the current value of the slider next to it.", sync=True)
     slider_color = Unicode(sync=True)
 
 
 @register('IPython.FloatProgress')
 class FloatProgress(_BoundedFloat):
     """ Displays a progress bar.
 
     Parameters
     -----------
     value : float
 	position within the range of the progress bar
     min : float
 	minimal position of the slider
     max : float
 	maximal position of the slider
     step : float
 	step of the progress bar
     description : str
 	name of the progress bar
     bar_style: {'success', 'info', 'warning', 'danger', ''}, optional
 	color of the progress bar, default is '' (blue)
 	colors are: 'success'-green, 'info'-light blue, 'warning'-orange, 'danger'-red
 """
     _view_name = Unicode('ProgressView', sync=True)
 
     bar_style = CaselessStrEnum(
         values=['success', 'info', 'warning', 'danger', ''], 
         default_value='', allow_none=True, sync=True, help="""Use a
         predefined styling for the progess bar.""")
 
 class _FloatRange(_Float):
     value = Tuple(CFloat, CFloat, default_value=(0.0, 1.0), help="Tuple of (lower, upper) bounds", sync=True)
     lower = CFloat(0.0, help="Lower bound", sync=False)
     upper = CFloat(1.0, help="Upper bound", sync=False)
     
     def __init__(self, *pargs, **kwargs):
         value_given = 'value' in kwargs
         lower_given = 'lower' in kwargs
         upper_given = 'upper' in kwargs
         if value_given and (lower_given or upper_given):
             raise ValueError("Cannot specify both 'value' and 'lower'/'upper' for range widget")
         if lower_given != upper_given:
             raise ValueError("Must specify both 'lower' and 'upper' for range widget")
         
         DOMWidget.__init__(self, *pargs, **kwargs)
         
         # ensure the traits match, preferring whichever (if any) was given in kwargs
         if value_given:
             self.lower, self.upper = self.value
         else:
             self.value = (self.lower, self.upper)
         
         self.on_trait_change(self._validate, ['value', 'upper', 'lower'])
     
     def _validate(self, name, old, new):
         if name == 'value':
             self.lower, self.upper = min(new), max(new)
         elif name == 'lower':
             self.value = (new, self.value[1])
         elif name == 'upper':
             self.value = (self.value[0], new)
 
 class _BoundedFloatRange(_FloatRange):
     step = CFloat(1.0, help="Minimum step that the value can take (ignored by some views)", sync=True)
     max = CFloat(100.0, help="Max value", sync=True)
     min = CFloat(0.0, help="Min value", sync=True)
     
     def __init__(self, *pargs, **kwargs):
         any_value_given = 'value' in kwargs or 'upper' in kwargs or 'lower' in kwargs
         _FloatRange.__init__(self, *pargs, **kwargs)
         
         # ensure a minimal amount of sanity
         if self.min > self.max:
             raise ValueError("min must be <= max")
         
         if any_value_given:
             # if a value was given, clamp it within (min, max)
             self._validate("value", None, self.value)
         else:
             # otherwise, set it to 25-75% to avoid the handles overlapping
             self.value = (0.75*self.min + 0.25*self.max,
                           0.25*self.min + 0.75*self.max)
         # callback already set for 'value', 'lower', 'upper'
         self.on_trait_change(self._validate, ['min', 'max'])
 
 
     def _validate(self, name, old, new):
         if name == "min":
             if new > self.max:
                 raise ValueError("setting min > max")
             self.min = new
         elif name == "max":
             if new < self.min:
                 raise ValueError("setting max < min")
             self.max = new
         
         low, high = self.value
         if name == "value":
             low, high = min(new), max(new)
         elif name == "upper":
             if new < self.lower:
                 raise ValueError("setting upper < lower")
             high = new
         elif name == "lower":
             if new > self.upper:
                 raise ValueError("setting lower > upper")
             low = new
         
         low = max(self.min, min(low, self.max))
         high = min(self.max, max(high, self.min))
         
         # determine the order in which we should update the
         # lower, upper traits to avoid a temporary inverted overlap
         lower_first = high < self.lower
         
         self.value = (low, high)
         if lower_first:
             self.lower = low
             self.upper = high
         else:
             self.upper = high
             self.lower = low
 
 
 @register('IPython.FloatRangeSlider')
 class FloatRangeSlider(_BoundedFloatRange):
     """ Slider/trackbar for displaying a floating value range (within the specified range of values).
 
 	Parameters
 	----------
 	value : float tuple
 	    range of the slider displayed
 	min : float
 	    minimal position of the slider
 	max : float
 	    maximal position of the slider
 	step : float
 	    step of the trackbar
 	description : str
 	    name of the slider
 	orientation : {'vertical', 'horizontal}, optional
             default is horizontal
 	readout : {True, False}, optional
 	    default is True, display the current value of the slider next to it		
 	slider_color : str Unicode color code (eg. '#C13535'), optional 
 	    color of the slider 
 	color : str Unicode color code (eg. '#C13535'), optional
 	    color of the value displayed (if readout == True)
     """
     _view_name = Unicode('FloatSliderView', sync=True)
     orientation = CaselessStrEnum(values=['horizontal', 'vertical'], 
-        default_value='horizontal', allow_none=False, 
-        help="Vertical or horizontal.", sync=True)
+        default_value='horizontal', help="Vertical or horizontal.", sync=True)
     _range = Bool(True, help="Display a range selector", sync=True)
     readout = Bool(True, help="Display the current value of the slider next to it.", sync=True)
     slider_color = Unicode(sync=True)
 
 # Remove in IPython 4.0
 FloatTextWidget = DeprecatedClass(FloatText, 'FloatTextWidget')
 BoundedFloatTextWidget = DeprecatedClass(BoundedFloatText, 'BoundedFloatTextWidget')
 FloatSliderWidget = DeprecatedClass(FloatSlider, 'FloatSliderWidget')
 FloatProgressWidget = DeprecatedClass(FloatProgress, 'FloatProgressWidget')

IPython/html/widgets/widget_int.py

@@ -1,209 +1,207 b''
 """Int class.  
 
 Represents an unbounded int using a widget.
 """
 #-----------------------------------------------------------------------------
 # Copyright (c) 2013, the IPython Development Team.
 #
 # Distributed under the terms of the Modified BSD License.
 #
 # The full license is in the file COPYING.txt, distributed with this software.
 #-----------------------------------------------------------------------------
 
 #-----------------------------------------------------------------------------
 # Imports
 #-----------------------------------------------------------------------------
 from .widget import DOMWidget, register
 from IPython.utils.traitlets import Unicode, CInt, Bool, CaselessStrEnum, Tuple
 from IPython.utils.warn import DeprecatedClass
 
 #-----------------------------------------------------------------------------
 # Classes
 #-----------------------------------------------------------------------------
 class _Int(DOMWidget):
     """Base class used to create widgets that represent an int."""
     value = CInt(0, help="Int value", sync=True)
     disabled = Bool(False, help="Enable or disable user changes", sync=True)
     description = Unicode(help="Description of the value this widget represents", sync=True)
 
     def __init__(self, value=None, **kwargs):
         if value is not None:
             kwargs['value'] = value
         super(_Int, self).__init__(**kwargs)
 
 class _BoundedInt(_Int):
     """Base class used to create widgets that represent a int that is bounded
     by a minium and maximum."""
     step = CInt(1, help="Minimum step that the value can take (ignored by some views)", sync=True)
     max = CInt(100, help="Max value", sync=True)
     min = CInt(0, help="Min value", sync=True)
 
     def __init__(self, *pargs, **kwargs):
         """Constructor"""
         super(_BoundedInt, self).__init__(*pargs, **kwargs)
         self._handle_value_changed('value', None, self.value)
         self._handle_max_changed('max', None, self.max)
         self._handle_min_changed('min', None, self.min)
         self.on_trait_change(self._handle_value_changed, 'value')
         self.on_trait_change(self._handle_max_changed, 'max')
         self.on_trait_change(self._handle_min_changed, 'min')
 
     def _handle_value_changed(self, name, old, new):
         """Validate value."""
         if self.min > new or new > self.max:
             self.value = min(max(new, self.min), self.max)
 
     def _handle_max_changed(self, name, old, new):
         """Make sure the min is always <= the max."""
         if new < self.min:
             raise ValueError("setting max < min")
         if new < self.value:
             self.value = new
 
     def _handle_min_changed(self, name, old, new):
         """Make sure the max is always >= the min."""
         if new > self.max:
             raise ValueError("setting min > max")
         if new > self.value:
             self.value = new
 
 @register('IPython.IntText')
 class IntText(_Int):
     """Textbox widget that represents a int."""
     _view_name = Unicode('IntTextView', sync=True)
 
 
 @register('IPython.BoundedIntText')
 class BoundedIntText(_BoundedInt):
     """Textbox widget that represents a int bounded by a minimum and maximum value."""
     _view_name = Unicode('IntTextView', sync=True)
 
 
 @register('IPython.IntSlider')
 class IntSlider(_BoundedInt):
     """Slider widget that represents a int bounded by a minimum and maximum value."""
     _view_name = Unicode('IntSliderView', sync=True)
     orientation = CaselessStrEnum(values=['horizontal', 'vertical'], 
-        default_value='horizontal', allow_none=False, 
-        help="Vertical or horizontal.", sync=True)
+        default_value='horizontal', help="Vertical or horizontal.", sync=True)
     _range = Bool(False, help="Display a range selector", sync=True)
     readout = Bool(True, help="Display the current value of the slider next to it.", sync=True)
     slider_color = Unicode(sync=True)
 
 
 @register('IPython.IntProgress')
 class IntProgress(_BoundedInt):
     """Progress bar that represents a int bounded by a minimum and maximum value."""
     _view_name = Unicode('ProgressView', sync=True)
 
     bar_style = CaselessStrEnum(
         values=['success', 'info', 'warning', 'danger', ''], 
         default_value='', allow_none=True, sync=True, help="""Use a
         predefined styling for the progess bar.""")
 
 class _IntRange(_Int):
     value = Tuple(CInt, CInt, default_value=(0, 1), help="Tuple of (lower, upper) bounds", sync=True)
     lower = CInt(0, help="Lower bound", sync=False)
     upper = CInt(1, help="Upper bound", sync=False)
     
     def __init__(self, *pargs, **kwargs):
         value_given = 'value' in kwargs
         lower_given = 'lower' in kwargs
         upper_given = 'upper' in kwargs
         if value_given and (lower_given or upper_given):
             raise ValueError("Cannot specify both 'value' and 'lower'/'upper' for range widget")
         if lower_given != upper_given:
             raise ValueError("Must specify both 'lower' and 'upper' for range widget")
         
         super(_IntRange, self).__init__(*pargs, **kwargs)
         
         # ensure the traits match, preferring whichever (if any) was given in kwargs
         if value_given:
             self.lower, self.upper = self.value
         else:
             self.value = (self.lower, self.upper)
 
         self.on_trait_change(self._validate, ['value', 'upper', 'lower'])
     
     def _validate(self, name, old, new):
         if name == 'value':
             self.lower, self.upper = min(new), max(new)
         elif name == 'lower':
             self.value = (new, self.value[1])
         elif name == 'upper':
             self.value = (self.value[0], new)
 
 class _BoundedIntRange(_IntRange):
     step = CInt(1, help="Minimum step that the value can take (ignored by some views)", sync=True)
     max = CInt(100, help="Max value", sync=True)
     min = CInt(0, help="Min value", sync=True)
 
     def __init__(self, *pargs, **kwargs):
         any_value_given = 'value' in kwargs or 'upper' in kwargs or 'lower' in kwargs
         _IntRange.__init__(self, *pargs, **kwargs)
         
         # ensure a minimal amount of sanity
         if self.min > self.max:
             raise ValueError("min must be <= max")
         
         if any_value_given:
             # if a value was given, clamp it within (min, max)
             self._validate("value", None, self.value)
         else:
             # otherwise, set it to 25-75% to avoid the handles overlapping
             self.value = (0.75*self.min + 0.25*self.max,
                           0.25*self.min + 0.75*self.max)
         # callback already set for 'value', 'lower', 'upper'
         self.on_trait_change(self._validate, ['min', 'max'])
 
     def _validate(self, name, old, new):
         if name == "min":
             if new > self.max:
                 raise ValueError("setting min > max")
         elif name == "max":
             if new < self.min:
                 raise ValueError("setting max < min")
         
         low, high = self.value
         if name == "value":
             low, high = min(new), max(new)
         elif name == "upper":
             if new < self.lower:
                 raise ValueError("setting upper < lower")
             high = new
         elif name == "lower":
             if new > self.upper:
                 raise ValueError("setting lower > upper")
             low = new
         
         low = max(self.min, min(low, self.max))
         high = min(self.max, max(high, self.min))
         
         # determine the order in which we should update the
         # lower, upper traits to avoid a temporary inverted overlap
         lower_first = high < self.lower
         
         self.value = (low, high)
         if lower_first:
             self.lower = low
             self.upper = high
         else:
             self.upper = high
             self.lower = low
 
 @register('IPython.IntRangeSlider')
 class IntRangeSlider(_BoundedIntRange):
     """Slider widget that represents a pair of ints between a minimum and maximum value."""
     _view_name = Unicode('IntSliderView', sync=True)
     orientation = CaselessStrEnum(values=['horizontal', 'vertical'], 
-        default_value='horizontal', allow_none=False, 
-        help="Vertical or horizontal.", sync=True)
+        default_value='horizontal', help="Vertical or horizontal.", sync=True)
     _range = Bool(True, help="Display a range selector", sync=True)
     readout = Bool(True, help="Display the current value of the slider next to it.", sync=True)
     slider_color = Unicode(sync=True)
 
 # Remove in IPython 4.0
 IntTextWidget = DeprecatedClass(IntText, 'IntTextWidget')
 BoundedIntTextWidget = DeprecatedClass(BoundedIntText, 'BoundedIntTextWidget')
 IntSliderWidget = DeprecatedClass(IntSlider, 'IntSliderWidget')
 IntProgressWidget = DeprecatedClass(IntProgress, 'IntProgressWidget')

IPython/kernel/tests/test_message_spec.py

@@ -1,496 +1,496 b''
 """Test suite for our zeromq-based message specification."""
 
 # Copyright (c) IPython Development Team.
 # Distributed under the terms of the Modified BSD License.
 
 import re
 import sys
 from distutils.version import LooseVersion as V
 try:
     from queue import Empty  # Py 3
 except ImportError:
     from Queue import Empty  # Py 2
 
 import nose.tools as nt
 
 from IPython.utils.traitlets import (
     HasTraits, TraitError, Bool, Unicode, Dict, Integer, List, Enum,
 )
 from IPython.utils.py3compat import string_types, iteritems
 
 from .utils import TIMEOUT, start_global_kernel, flush_channels, execute
 
 #-----------------------------------------------------------------------------
 # Globals
 #-----------------------------------------------------------------------------
 KC = None
 
 def setup():
     global KC
     KC = start_global_kernel()
 
 #-----------------------------------------------------------------------------
 # Message Spec References
 #-----------------------------------------------------------------------------
 
 class Reference(HasTraits):
 
     """
     Base class for message spec specification testing.
 
     This class is the core of the message specification test.  The
     idea is that child classes implement trait attributes for each
     message keys, so that message keys can be tested against these
     traits using :meth:`check` method.
 
     """
 
     def check(self, d):
         """validate a dict against our traits"""
         for key in self.trait_names():
             nt.assert_in(key, d)
             # FIXME: always allow None, probably not a good idea
             if d[key] is None:
                 continue
             try:
                 setattr(self, key, d[key])
             except TraitError as e:
                 assert False, str(e)
 
 
 class Version(Unicode):
     def __init__(self, *args, **kwargs):
         self.min = kwargs.pop('min', None)
         self.max = kwargs.pop('max', None)
         kwargs['default_value'] = self.min
         super(Version, self).__init__(*args, **kwargs)
     
     def validate(self, obj, value):
         if self.min and V(value) < V(self.min):
             raise TraitError("bad version: %s < %s" % (value, self.min))
         if self.max and (V(value) > V(self.max)):
             raise TraitError("bad version: %s > %s" % (value, self.max))
 
 
 class RMessage(Reference):
     msg_id = Unicode()
     msg_type = Unicode()
     header = Dict()
     parent_header = Dict()
     content = Dict()
     
     def check(self, d):
         super(RMessage, self).check(d)
         RHeader().check(self.header)
         if self.parent_header:
             RHeader().check(self.parent_header)
 
 class RHeader(Reference):
     msg_id = Unicode()
     msg_type = Unicode()
     session = Unicode()
     username = Unicode()
     version = Version(min='5.0')
 
 mime_pat = re.compile(r'^[\w\-\+\.]+/[\w\-\+\.]+$')
 
 class MimeBundle(Reference):
     metadata = Dict()
     data = Dict()
     def _data_changed(self, name, old, new):
         for k,v in iteritems(new):
             assert mime_pat.match(k)
             nt.assert_is_instance(v, string_types)
 
 # shell replies
 
 class ExecuteReply(Reference):
     execution_count = Integer()
-    status = Enum((u'ok', u'error'))
+    status = Enum((u'ok', u'error'), default_value=u'ok')
     
     def check(self, d):
         Reference.check(self, d)
         if d['status'] == 'ok':
             ExecuteReplyOkay().check(d)
         elif d['status'] == 'error':
             ExecuteReplyError().check(d)
 
 
 class ExecuteReplyOkay(Reference):
     payload = List(Dict)
     user_expressions = Dict()
 
 
 class ExecuteReplyError(Reference):
     ename = Unicode()
     evalue = Unicode()
     traceback = List(Unicode)
 
 
 class InspectReply(MimeBundle):
     found = Bool()
 
 
 class ArgSpec(Reference):
     args = List(Unicode)
     varargs = Unicode()
     varkw = Unicode()
     defaults = List()
 
 
 class Status(Reference):
-    execution_state = Enum((u'busy', u'idle', u'starting'))
+    execution_state = Enum((u'busy', u'idle', u'starting'), default_value=u'busy')
 
 
 class CompleteReply(Reference):
     matches = List(Unicode)
     cursor_start = Integer()
     cursor_end = Integer()
     status = Unicode()
 
 class LanguageInfo(Reference):
     name = Unicode('python')
     version = Unicode(sys.version.split()[0])
 
 class KernelInfoReply(Reference):
     protocol_version = Version(min='5.0')
     implementation = Unicode('ipython')
     implementation_version = Version(min='2.1')
     language_info = Dict()
     banner = Unicode()
     
     def check(self, d):
         Reference.check(self, d)
         LanguageInfo().check(d['language_info'])
 
 
 class IsCompleteReply(Reference):
-    status = Enum((u'complete', u'incomplete', u'invalid', u'unknown'))
+    status = Enum((u'complete', u'incomplete', u'invalid', u'unknown'), default_value=u'complete')
     
     def check(self, d):
         Reference.check(self, d)
         if d['status'] == 'incomplete':
             IsCompleteReplyIncomplete().check(d)
 
 class IsCompleteReplyIncomplete(Reference):
     indent = Unicode()
 
 
 # IOPub messages
 
 class ExecuteInput(Reference):
     code = Unicode()
     execution_count = Integer()
 
 
 Error = ExecuteReplyError
 
 
 class Stream(Reference):
-    name = Enum((u'stdout', u'stderr'))
+    name = Enum((u'stdout', u'stderr'), default_value=u'stdout')
     text = Unicode()
 
 
 class DisplayData(MimeBundle):
     pass
 
 
 class ExecuteResult(MimeBundle):
     execution_count = Integer()
 
 class HistoryReply(Reference):
     history = List(List())
 
 
 references = {
     'execute_reply' : ExecuteReply(),
     'inspect_reply' : InspectReply(),
     'status' : Status(),
     'complete_reply' : CompleteReply(),
     'kernel_info_reply': KernelInfoReply(),
     'is_complete_reply': IsCompleteReply(),
     'execute_input' : ExecuteInput(),
     'execute_result' : ExecuteResult(),
     'history_reply' : HistoryReply(),
     'error' : Error(),
     'stream' : Stream(),
     'display_data' : DisplayData(),
     'header' : RHeader(),
 }
 """
 Specifications of `content` part of the reply messages.
 """
 
 
 def validate_message(msg, msg_type=None, parent=None):
     """validate a message
     
     This is a generator, and must be iterated through to actually
     trigger each test.
     
     If msg_type and/or parent are given, the msg_type and/or parent msg_id
     are compared with the given values.
     """
     RMessage().check(msg)
     if msg_type:
         nt.assert_equal(msg['msg_type'], msg_type)
     if parent:
         nt.assert_equal(msg['parent_header']['msg_id'], parent)
     content = msg['content']
     ref = references[msg['msg_type']]
     ref.check(content)
 
 
 #-----------------------------------------------------------------------------
 # Tests
 #-----------------------------------------------------------------------------
 
 # Shell channel
 
 def test_execute():
     flush_channels()
     
     msg_id = KC.execute(code='x=1')
     reply = KC.get_shell_msg(timeout=TIMEOUT)
     validate_message(reply, 'execute_reply', msg_id)
 
 
 def test_execute_silent():
     flush_channels()
     msg_id, reply = execute(code='x=1', silent=True)
     
     # flush status=idle
     status = KC.iopub_channel.get_msg(timeout=TIMEOUT)
     validate_message(status, 'status', msg_id)
     nt.assert_equal(status['content']['execution_state'], 'idle')
 
     nt.assert_raises(Empty, KC.iopub_channel.get_msg, timeout=0.1)
     count = reply['execution_count']
     
     msg_id, reply = execute(code='x=2', silent=True)
     
     # flush status=idle
     status = KC.iopub_channel.get_msg(timeout=TIMEOUT)
     validate_message(status, 'status', msg_id)
     nt.assert_equal(status['content']['execution_state'], 'idle')
     
     nt.assert_raises(Empty, KC.iopub_channel.get_msg, timeout=0.1)
     count_2 = reply['execution_count']
     nt.assert_equal(count_2, count)
 
 
 def test_execute_error():
     flush_channels()
     
     msg_id, reply = execute(code='1/0')
     nt.assert_equal(reply['status'], 'error')
     nt.assert_equal(reply['ename'], 'ZeroDivisionError')
     
     error = KC.iopub_channel.get_msg(timeout=TIMEOUT)
     validate_message(error, 'error', msg_id)
 
 
 def test_execute_inc():
     """execute request should increment execution_count"""
     flush_channels()
 
     msg_id, reply = execute(code='x=1')
     count = reply['execution_count']
     
     flush_channels()
     
     msg_id, reply = execute(code='x=2')
     count_2 = reply['execution_count']
     nt.assert_equal(count_2, count+1)
 
 def test_execute_stop_on_error():
     """execute request should not abort execution queue with stop_on_error False"""
     flush_channels()
     
     fail = '\n'.join([
         # sleep to ensure subsequent message is waiting in the queue to be aborted
         'import time',
         'time.sleep(0.5)',
         'raise ValueError',
     ])
     KC.execute(code=fail)
     msg_id = KC.execute(code='print("Hello")')
     KC.get_shell_msg(timeout=TIMEOUT)
     reply = KC.get_shell_msg(timeout=TIMEOUT)
     nt.assert_equal(reply['content']['status'], 'aborted')
 
     flush_channels()
 
     KC.execute(code=fail, stop_on_error=False)
     msg_id = KC.execute(code='print("Hello")')
     KC.get_shell_msg(timeout=TIMEOUT)
     reply = KC.get_shell_msg(timeout=TIMEOUT)
     nt.assert_equal(reply['content']['status'], 'ok')
 
 
 def test_user_expressions():
     flush_channels()
 
     msg_id, reply = execute(code='x=1', user_expressions=dict(foo='x+1'))
     user_expressions = reply['user_expressions']
     nt.assert_equal(user_expressions, {u'foo': {
         u'status': u'ok',
         u'data': {u'text/plain': u'2'},
         u'metadata': {},
     }})
 
 
 def test_user_expressions_fail():
     flush_channels()
 
     msg_id, reply = execute(code='x=0', user_expressions=dict(foo='nosuchname'))
     user_expressions = reply['user_expressions']
     foo = user_expressions['foo']
     nt.assert_equal(foo['status'], 'error')
     nt.assert_equal(foo['ename'], 'NameError')
 
 
 def test_oinfo():
     flush_channels()
 
     msg_id = KC.inspect('a')
     reply = KC.get_shell_msg(timeout=TIMEOUT)
     validate_message(reply, 'inspect_reply', msg_id)
 
 
 def test_oinfo_found():
     flush_channels()
 
     msg_id, reply = execute(code='a=5')
     
     msg_id = KC.inspect('a')
     reply = KC.get_shell_msg(timeout=TIMEOUT)
     validate_message(reply, 'inspect_reply', msg_id)
     content = reply['content']
     assert content['found']
     text = content['data']['text/plain']
     nt.assert_in('Type:', text)
     nt.assert_in('Docstring:', text)
 
 
 def test_oinfo_detail():
     flush_channels()
 
     msg_id, reply = execute(code='ip=get_ipython()')
     
     msg_id = KC.inspect('ip.object_inspect', cursor_pos=10, detail_level=1)
     reply = KC.get_shell_msg(timeout=TIMEOUT)
     validate_message(reply, 'inspect_reply', msg_id)
     content = reply['content']
     assert content['found']
     text = content['data']['text/plain']
     nt.assert_in('Signature:', text)
     nt.assert_in('Source:', text)
 
 
 def test_oinfo_not_found():
     flush_channels()
 
     msg_id = KC.inspect('dne')
     reply = KC.get_shell_msg(timeout=TIMEOUT)
     validate_message(reply, 'inspect_reply', msg_id)
     content = reply['content']
     nt.assert_false(content['found'])
 
 
 def test_complete():
     flush_channels()
 
     msg_id, reply = execute(code="alpha = albert = 5")
     
     msg_id = KC.complete('al', 2)
     reply = KC.get_shell_msg(timeout=TIMEOUT)
     validate_message(reply, 'complete_reply', msg_id)
     matches = reply['content']['matches']
     for name in ('alpha', 'albert'):
         nt.assert_in(name, matches)
 
 
 def test_kernel_info_request():
     flush_channels()
 
     msg_id = KC.kernel_info()
     reply = KC.get_shell_msg(timeout=TIMEOUT)
     validate_message(reply, 'kernel_info_reply', msg_id)
 
 
 def test_single_payload():
     flush_channels()
     msg_id, reply = execute(code="for i in range(3):\n"+
                                  "   x=range?\n")
     payload = reply['payload']
     next_input_pls = [pl for pl in payload if pl["source"] == "set_next_input"]
     nt.assert_equal(len(next_input_pls), 1)
 
 def test_is_complete():
     flush_channels()
 
     msg_id = KC.is_complete("a = 1")
     reply = KC.get_shell_msg(timeout=TIMEOUT)
     validate_message(reply, 'is_complete_reply', msg_id)
 
 def test_history_range():
     flush_channels()
     
     msg_id_exec = KC.execute(code='x=1', store_history = True)
     reply_exec = KC.get_shell_msg(timeout=TIMEOUT)
     
     msg_id = KC.history(hist_access_type = 'range', raw = True, output = True, start = 1, stop = 2, session = 0)
     reply = KC.get_shell_msg(timeout=TIMEOUT)
     validate_message(reply, 'history_reply', msg_id)
     content = reply['content']
     nt.assert_equal(len(content['history']), 1)
 
 def test_history_tail():
     flush_channels()
     
     msg_id_exec = KC.execute(code='x=1', store_history = True)
     reply_exec = KC.get_shell_msg(timeout=TIMEOUT)
     
     msg_id = KC.history(hist_access_type = 'tail', raw = True, output = True, n = 1, session = 0)
     reply = KC.get_shell_msg(timeout=TIMEOUT)
     validate_message(reply, 'history_reply', msg_id)
     content = reply['content']
     nt.assert_equal(len(content['history']), 1)
 
 def test_history_search():
     flush_channels()
     
     msg_id_exec = KC.execute(code='x=1', store_history = True)
     reply_exec = KC.get_shell_msg(timeout=TIMEOUT)
     
     msg_id = KC.history(hist_access_type = 'search', raw = True, output = True, n = 1, pattern = '*', session = 0)
     reply = KC.get_shell_msg(timeout=TIMEOUT)
     validate_message(reply, 'history_reply', msg_id)
     content = reply['content']
     nt.assert_equal(len(content['history']), 1)
 
 # IOPub channel
 
 
 def test_stream():
     flush_channels()
 
     msg_id, reply = execute("print('hi')")
 
     stdout = KC.iopub_channel.get_msg(timeout=TIMEOUT)
     validate_message(stdout, 'stream', msg_id)
     content = stdout['content']
     nt.assert_equal(content['text'], u'hi\n')
 
 
 def test_display_data():
     flush_channels()
 
     msg_id, reply = execute("from IPython.core.display import display; display(1)")
     
     display = KC.iopub_channel.get_msg(timeout=TIMEOUT)
     validate_message(display, 'display_data', parent=msg_id)
     data = display['content']['data']
     nt.assert_equal(data['text/plain'], u'1')
 

IPython/parallel/controller/scheduler.py

@@ -1,849 +1,849 b''
 """The Python scheduler for rich scheduling.
 
 The Pure ZMQ scheduler does not allow routing schemes other than LRU,
 nor does it check msg_id DAG dependencies. For those, a slightly slower
 Python Scheduler exists.
 """
 
 # Copyright (c) IPython Development Team.
 # Distributed under the terms of the Modified BSD License.
 
 import logging
 import sys
 import time
 
 from collections import deque
 from datetime import datetime
 from random import randint, random
 from types import FunctionType
 
 try:
     import numpy
 except ImportError:
     numpy = None
 
 import zmq
 from zmq.eventloop import ioloop, zmqstream
 
 # local imports
 from IPython.external.decorator import decorator
 from IPython.config.application import Application
 from IPython.config.loader import Config
 from IPython.utils.traitlets import Instance, Dict, List, Set, Integer, Enum, CBytes
 from IPython.utils.py3compat import cast_bytes
 
 from IPython.parallel import error, util
 from IPython.parallel.factory import SessionFactory
 from IPython.parallel.util import connect_logger, local_logger
 
 from .dependency import Dependency
 
 @decorator
 def logged(f,self,*args,**kwargs):
     # print ("#--------------------")
     self.log.debug("scheduler::%s(*%s,**%s)", f.__name__, args, kwargs)
     # print ("#--")
     return f(self,*args, **kwargs)
 
 #----------------------------------------------------------------------
 # Chooser functions
 #----------------------------------------------------------------------
 
 def plainrandom(loads):
     """Plain random pick."""
     n = len(loads)
     return randint(0,n-1)
 
 def lru(loads):
     """Always pick the front of the line.
 
     The content of `loads` is ignored.
 
     Assumes LRU ordering of loads, with oldest first.
     """
     return 0
 
 def twobin(loads):
     """Pick two at random, use the LRU of the two.
 
     The content of loads is ignored.
 
     Assumes LRU ordering of loads, with oldest first.
     """
     n = len(loads)
     a = randint(0,n-1)
     b = randint(0,n-1)
     return min(a,b)
 
 def weighted(loads):
     """Pick two at random using inverse load as weight.
 
     Return the less loaded of the two.
     """
     # weight 0 a million times more than 1:
     weights = 1./(1e-6+numpy.array(loads))
     sums = weights.cumsum()
     t = sums[-1]
     x = random()*t
     y = random()*t
     idx = 0
     idy = 0
     while sums[idx] < x:
         idx += 1
     while sums[idy] < y:
         idy += 1
     if weights[idy] > weights[idx]:
         return idy
     else:
         return idx
 
 def leastload(loads):
     """Always choose the lowest load.
 
     If the lowest load occurs more than once, the first
     occurance will be used.  If loads has LRU ordering, this means
     the LRU of those with the lowest load is chosen.
     """
     return loads.index(min(loads))
 
 #---------------------------------------------------------------------
 # Classes
 #---------------------------------------------------------------------
 
 
 # store empty default dependency:
 MET = Dependency([])
 
 
 class Job(object):
     """Simple container for a job"""
     def __init__(self, msg_id, raw_msg, idents, msg, header, metadata,
                     targets, after, follow, timeout):
         self.msg_id = msg_id
         self.raw_msg = raw_msg
         self.idents = idents
         self.msg = msg
         self.header = header
         self.metadata = metadata
         self.targets = targets
         self.after = after
         self.follow = follow
         self.timeout = timeout
         
         self.removed = False # used for lazy-delete from sorted queue
         self.timestamp = time.time()
         self.timeout_id = 0
         self.blacklist = set()
 
     def __lt__(self, other):
         return self.timestamp < other.timestamp
 
     def __cmp__(self, other):
         return cmp(self.timestamp, other.timestamp)
 
     @property
     def dependents(self):
         return self.follow.union(self.after)
 
 
 class TaskScheduler(SessionFactory):
     """Python TaskScheduler object.
 
     This is the simplest object that supports msg_id based
     DAG dependencies. *Only* task msg_ids are checked, not
     msg_ids of jobs submitted via the MUX queue.
 
     """
 
     hwm = Integer(1, config=True,
         help="""specify the High Water Mark (HWM) for the downstream
         socket in the Task scheduler. This is the maximum number
         of allowed outstanding tasks on each engine.
         
         The default (1) means that only one task can be outstanding on each
         engine.  Setting TaskScheduler.hwm=0 means there is no limit, and the
         engines continue to be assigned tasks while they are working,
         effectively hiding network latency behind computation, but can result
         in an imbalance of work when submitting many heterogenous tasks all at
         once.  Any positive value greater than one is a compromise between the
         two.
 
         """
     )
     scheme_name = Enum(('leastload', 'pure', 'lru', 'plainrandom', 'weighted', 'twobin'),
-        'leastload', config=True, allow_none=False,
+        'leastload', config=True,
         help="""select the task scheduler scheme  [default: Python LRU]
         Options are: 'pure', 'lru', 'plainrandom', 'weighted', 'twobin','leastload'"""
     )
     def _scheme_name_changed(self, old, new):
         self.log.debug("Using scheme %r"%new)
         self.scheme = globals()[new]
 
     # input arguments:
     scheme = Instance(FunctionType) # function for determining the destination
     def _scheme_default(self):
         return leastload
     client_stream = Instance(zmqstream.ZMQStream) # client-facing stream
     engine_stream = Instance(zmqstream.ZMQStream) # engine-facing stream
     notifier_stream = Instance(zmqstream.ZMQStream) # hub-facing sub stream
     mon_stream = Instance(zmqstream.ZMQStream) # hub-facing pub stream
     query_stream = Instance(zmqstream.ZMQStream) # hub-facing DEALER stream
 
     # internals:
     queue = Instance(deque) # sorted list of Jobs
     def _queue_default(self):
         return deque()
     queue_map = Dict() # dict by msg_id of Jobs (for O(1) access to the Queue)
     graph = Dict() # dict by msg_id of [ msg_ids that depend on key ]
     retries = Dict() # dict by msg_id of retries remaining (non-neg ints)
     # waiting = List() # list of msg_ids ready to run, but haven't due to HWM
     pending = Dict() # dict by engine_uuid of submitted tasks
     completed = Dict() # dict by engine_uuid of completed tasks
     failed = Dict() # dict by engine_uuid of failed tasks
     destinations = Dict() # dict by msg_id of engine_uuids where jobs ran (reverse of completed+failed)
     clients = Dict() # dict by msg_id for who submitted the task
     targets = List() # list of target IDENTs
     loads = List() # list of engine loads
     # full = Set() # set of IDENTs that have HWM outstanding tasks
     all_completed = Set() # set of all completed tasks
     all_failed = Set() # set of all failed tasks
     all_done = Set() # set of all finished tasks=union(completed,failed)
     all_ids = Set() # set of all submitted task IDs
 
     ident = CBytes() # ZMQ identity. This should just be self.session.session
                      # but ensure Bytes
     def _ident_default(self):
         return self.session.bsession
 
     def start(self):
         self.query_stream.on_recv(self.dispatch_query_reply)
         self.session.send(self.query_stream, "connection_request", {})
         
         self.engine_stream.on_recv(self.dispatch_result, copy=False)
         self.client_stream.on_recv(self.dispatch_submission, copy=False)
 
         self._notification_handlers = dict(
             registration_notification = self._register_engine,
             unregistration_notification = self._unregister_engine
         )
         self.notifier_stream.on_recv(self.dispatch_notification)
         self.log.info("Scheduler started [%s]" % self.scheme_name)
 
     def resume_receiving(self):
         """Resume accepting jobs."""
         self.client_stream.on_recv(self.dispatch_submission, copy=False)
 
     def stop_receiving(self):
         """Stop accepting jobs while there are no engines.
         Leave them in the ZMQ queue."""
         self.client_stream.on_recv(None)
 
     #-----------------------------------------------------------------------
     # [Un]Registration Handling
     #-----------------------------------------------------------------------
     
     
     def dispatch_query_reply(self, msg):
         """handle reply to our initial connection request"""
         try:
             idents,msg = self.session.feed_identities(msg)
         except ValueError:
             self.log.warn("task::Invalid Message: %r",msg)
             return
         try:
             msg = self.session.deserialize(msg)
         except ValueError:
             self.log.warn("task::Unauthorized message from: %r"%idents)
             return
         
         content = msg['content']
         for uuid in content.get('engines', {}).values():
             self._register_engine(cast_bytes(uuid))
 
     
     @util.log_errors
     def dispatch_notification(self, msg):
         """dispatch register/unregister events."""
         try:
             idents,msg = self.session.feed_identities(msg)
         except ValueError:
             self.log.warn("task::Invalid Message: %r",msg)
             return
         try:
             msg = self.session.deserialize(msg)
         except ValueError:
             self.log.warn("task::Unauthorized message from: %r"%idents)
             return
 
         msg_type = msg['header']['msg_type']
 
         handler = self._notification_handlers.get(msg_type, None)
         if handler is None:
             self.log.error("Unhandled message type: %r"%msg_type)
         else:
             try:
                 handler(cast_bytes(msg['content']['uuid']))
             except Exception:
                 self.log.error("task::Invalid notification msg: %r", msg, exc_info=True)
 
     def _register_engine(self, uid):
         """New engine with ident `uid` became available."""
         # head of the line:
         self.targets.insert(0,uid)
         self.loads.insert(0,0)
 
         # initialize sets
         self.completed[uid] = set()
         self.failed[uid] = set()
         self.pending[uid] = {}
 
         # rescan the graph:
         self.update_graph(None)
 
     def _unregister_engine(self, uid):
         """Existing engine with ident `uid` became unavailable."""
         if len(self.targets) == 1:
             # this was our only engine
             pass
 
         # handle any potentially finished tasks:
         self.engine_stream.flush()
 
         # don't pop destinations, because they might be used later
         # map(self.destinations.pop, self.completed.pop(uid))
         # map(self.destinations.pop, self.failed.pop(uid))
 
         # prevent this engine from receiving work
         idx = self.targets.index(uid)
         self.targets.pop(idx)
         self.loads.pop(idx)
 
         # wait 5 seconds before cleaning up pending jobs, since the results might
         # still be incoming
         if self.pending[uid]:
             self.loop.add_timeout(self.loop.time() + 5,
                 lambda : self.handle_stranded_tasks(uid),
             )
         else:
             self.completed.pop(uid)
             self.failed.pop(uid)
 
 
     def handle_stranded_tasks(self, engine):
         """Deal with jobs resident in an engine that died."""
         lost = self.pending[engine]
         for msg_id in lost.keys():
             if msg_id not in self.pending[engine]:
                 # prevent double-handling of messages
                 continue
 
             raw_msg = lost[msg_id].raw_msg
             idents,msg = self.session.feed_identities(raw_msg, copy=False)
             parent = self.session.unpack(msg[1].bytes)
             idents = [engine, idents[0]]
 
             # build fake error reply
             try:
                 raise error.EngineError("Engine %r died while running task %r"%(engine, msg_id))
             except:
                 content = error.wrap_exception()
             # build fake metadata
             md = dict(
                 status=u'error',
                 engine=engine.decode('ascii'),
                 date=datetime.now(),
             )
             msg = self.session.msg('apply_reply', content, parent=parent, metadata=md)
             raw_reply = list(map(zmq.Message, self.session.serialize(msg, ident=idents)))
             # and dispatch it
             self.dispatch_result(raw_reply)
 
         # finally scrub completed/failed lists
         self.completed.pop(engine)
         self.failed.pop(engine)
 
 
     #-----------------------------------------------------------------------
     # Job Submission
     #-----------------------------------------------------------------------
     
 
     @util.log_errors
     def dispatch_submission(self, raw_msg):
         """Dispatch job submission to appropriate handlers."""
         # ensure targets up to date:
         self.notifier_stream.flush()
         try:
             idents, msg = self.session.feed_identities(raw_msg, copy=False)
             msg = self.session.deserialize(msg, content=False, copy=False)
         except Exception:
             self.log.error("task::Invaid task msg: %r"%raw_msg, exc_info=True)
             return
 
 
         # send to monitor
         self.mon_stream.send_multipart([b'intask']+raw_msg, copy=False)
 
         header = msg['header']
         md = msg['metadata']
         msg_id = header['msg_id']
         self.all_ids.add(msg_id)
 
         # get targets as a set of bytes objects
         # from a list of unicode objects
         targets = md.get('targets', [])
         targets = set(map(cast_bytes, targets))
 
         retries = md.get('retries', 0)
         self.retries[msg_id] = retries
 
         # time dependencies
         after = md.get('after', None)
         if after:
             after = Dependency(after)
             if after.all:
                 if after.success:
                     after = Dependency(after.difference(self.all_completed),
                                 success=after.success,
                                 failure=after.failure,
                                 all=after.all,
                     )
                 if after.failure:
                     after = Dependency(after.difference(self.all_failed),
                                 success=after.success,
                                 failure=after.failure,
                                 all=after.all,
                     )
             if after.check(self.all_completed, self.all_failed):
                 # recast as empty set, if `after` already met,
                 # to prevent unnecessary set comparisons
                 after = MET
         else:
             after = MET
 
         # location dependencies
         follow = Dependency(md.get('follow', []))
 
         timeout = md.get('timeout', None)
         if timeout:
             timeout = float(timeout)
 
         job = Job(msg_id=msg_id, raw_msg=raw_msg, idents=idents, msg=msg,
                  header=header, targets=targets, after=after, follow=follow,
                  timeout=timeout, metadata=md,
         )
         # validate and reduce dependencies:
         for dep in after,follow:
             if not dep: # empty dependency
                 continue
             # check valid:
             if msg_id in dep or dep.difference(self.all_ids):
                 self.queue_map[msg_id] = job
                 return self.fail_unreachable(msg_id, error.InvalidDependency)
             # check if unreachable:
             if dep.unreachable(self.all_completed, self.all_failed):
                 self.queue_map[msg_id] = job
                 return self.fail_unreachable(msg_id)
 
         if after.check(self.all_completed, self.all_failed):
             # time deps already met, try to run
             if not self.maybe_run(job):
                 # can't run yet
                 if msg_id not in self.all_failed:
                     # could have failed as unreachable
                     self.save_unmet(job)
         else:
             self.save_unmet(job)
 
     def job_timeout(self, job, timeout_id):
         """callback for a job's timeout.
         
         The job may or may not have been run at this point.
         """
         if job.timeout_id != timeout_id:
             # not the most recent call
             return
         now = time.time()
         if job.timeout >= (now + 1):
             self.log.warn("task %s timeout fired prematurely: %s > %s",
                 job.msg_id, job.timeout, now
             )
         if job.msg_id in self.queue_map:
             # still waiting, but ran out of time
             self.log.info("task %r timed out", job.msg_id)
             self.fail_unreachable(job.msg_id, error.TaskTimeout)
 
     def fail_unreachable(self, msg_id, why=error.ImpossibleDependency):
         """a task has become unreachable, send a reply with an ImpossibleDependency
         error."""
         if msg_id not in self.queue_map:
             self.log.error("task %r already failed!", msg_id)
             return
         job = self.queue_map.pop(msg_id)
         # lazy-delete from the queue
         job.removed = True
         for mid in job.dependents:
             if mid in self.graph:
                 self.graph[mid].remove(msg_id)
 
         try:
             raise why()
         except:
             content = error.wrap_exception()
         self.log.debug("task %r failing as unreachable with: %s", msg_id, content['ename'])
 
         self.all_done.add(msg_id)
         self.all_failed.add(msg_id)
 
         msg = self.session.send(self.client_stream, 'apply_reply', content,
                                                 parent=job.header, ident=job.idents)
         self.session.send(self.mon_stream, msg, ident=[b'outtask']+job.idents)
 
         self.update_graph(msg_id, success=False)
 
     def available_engines(self):
         """return a list of available engine indices based on HWM"""
         if not self.hwm:
             return list(range(len(self.targets)))
         available = []
         for idx in range(len(self.targets)):
             if self.loads[idx] < self.hwm:
                 available.append(idx)
         return available
 
     def maybe_run(self, job):
         """check location dependencies, and run if they are met."""
         msg_id = job.msg_id
         self.log.debug("Attempting to assign task %s", msg_id)
         available = self.available_engines()
         if not available:
             # no engines, definitely can't run
             return False
         
         if job.follow or job.targets or job.blacklist or self.hwm:
             # we need a can_run filter
             def can_run(idx):
                 # check hwm
                 if self.hwm and self.loads[idx] == self.hwm:
                     return False
                 target = self.targets[idx]
                 # check blacklist
                 if target in job.blacklist:
                     return False
                 # check targets
                 if job.targets and target not in job.targets:
                     return False
                 # check follow
                 return job.follow.check(self.completed[target], self.failed[target])
 
             indices = list(filter(can_run, available))
 
             if not indices:
                 # couldn't run
                 if job.follow.all:
                     # check follow for impossibility
                     dests = set()
                     relevant = set()
                     if job.follow.success:
                         relevant = self.all_completed
                     if job.follow.failure:
                         relevant = relevant.union(self.all_failed)
                     for m in job.follow.intersection(relevant):
                         dests.add(self.destinations[m])
                     if len(dests) > 1:
                         self.queue_map[msg_id] = job
                         self.fail_unreachable(msg_id)
                         return False
                 if job.targets:
                     # check blacklist+targets for impossibility
                     job.targets.difference_update(job.blacklist)
                     if not job.targets or not job.targets.intersection(self.targets):
                         self.queue_map[msg_id] = job
                         self.fail_unreachable(msg_id)
                         return False
                 return False
         else:
             indices = None
 
         self.submit_task(job, indices)
         return True
 
     def save_unmet(self, job):
         """Save a message for later submission when its dependencies are met."""
         msg_id = job.msg_id
         self.log.debug("Adding task %s to the queue", msg_id)
         self.queue_map[msg_id] = job
         self.queue.append(job)
         # track the ids in follow or after, but not those already finished
         for dep_id in job.after.union(job.follow).difference(self.all_done):
             if dep_id not in self.graph:
                 self.graph[dep_id] = set()
             self.graph[dep_id].add(msg_id)
         
         # schedule timeout callback
         if job.timeout:
             timeout_id = job.timeout_id = job.timeout_id + 1
             self.loop.add_timeout(time.time() + job.timeout,
                 lambda : self.job_timeout(job, timeout_id)
             )
         
 
     def submit_task(self, job, indices=None):
         """Submit a task to any of a subset of our targets."""
         if indices:
             loads = [self.loads[i] for i in indices]
         else:
             loads = self.loads
         idx = self.scheme(loads)
         if indices:
             idx = indices[idx]
         target = self.targets[idx]
         # print (target, map(str, msg[:3]))
         # send job to the engine
         self.engine_stream.send(target, flags=zmq.SNDMORE, copy=False)
         self.engine_stream.send_multipart(job.raw_msg, copy=False)
         # update load
         self.add_job(idx)
         self.pending[target][job.msg_id] = job
         # notify Hub
         content = dict(msg_id=job.msg_id, engine_id=target.decode('ascii'))
         self.session.send(self.mon_stream, 'task_destination', content=content,
                         ident=[b'tracktask',self.ident])
 
 
     #-----------------------------------------------------------------------
     # Result Handling
     #-----------------------------------------------------------------------
     
     
     @util.log_errors
     def dispatch_result(self, raw_msg):
         """dispatch method for result replies"""
         try:
             idents,msg = self.session.feed_identities(raw_msg, copy=False)
             msg = self.session.deserialize(msg, content=False, copy=False)
             engine = idents[0]
             try:
                 idx = self.targets.index(engine)
             except ValueError:
                 pass # skip load-update for dead engines
             else:
                 self.finish_job(idx)
         except Exception:
             self.log.error("task::Invalid result: %r", raw_msg, exc_info=True)
             return
 
         md = msg['metadata']
         parent = msg['parent_header']
         if md.get('dependencies_met', True):
             success = (md['status'] == 'ok')
             msg_id = parent['msg_id']
             retries = self.retries[msg_id]
             if not success and retries > 0:
                 # failed
                 self.retries[msg_id] = retries - 1
                 self.handle_unmet_dependency(idents, parent)
             else:
                 del self.retries[msg_id]
                 # relay to client and update graph
                 self.handle_result(idents, parent, raw_msg, success)
                 # send to Hub monitor
                 self.mon_stream.send_multipart([b'outtask']+raw_msg, copy=False)
         else:
             self.handle_unmet_dependency(idents, parent)
 
     def handle_result(self, idents, parent, raw_msg, success=True):
         """handle a real task result, either success or failure"""
         # first, relay result to client
         engine = idents[0]
         client = idents[1]
         # swap_ids for ROUTER-ROUTER mirror
         raw_msg[:2] = [client,engine]
         # print (map(str, raw_msg[:4]))
         self.client_stream.send_multipart(raw_msg, copy=False)
         # now, update our data structures
         msg_id = parent['msg_id']
         self.pending[engine].pop(msg_id)
         if success:
             self.completed[engine].add(msg_id)
             self.all_completed.add(msg_id)
         else:
             self.failed[engine].add(msg_id)
             self.all_failed.add(msg_id)
         self.all_done.add(msg_id)
         self.destinations[msg_id] = engine
 
         self.update_graph(msg_id, success)
 
     def handle_unmet_dependency(self, idents, parent):
         """handle an unmet dependency"""
         engine = idents[0]
         msg_id = parent['msg_id']
 
         job = self.pending[engine].pop(msg_id)
         job.blacklist.add(engine)
 
         if job.blacklist == job.targets:
             self.queue_map[msg_id] = job
             self.fail_unreachable(msg_id)
         elif not self.maybe_run(job):
             # resubmit failed
             if msg_id not in self.all_failed:
                 # put it back in our dependency tree
                 self.save_unmet(job)
 
         if self.hwm:
             try:
                 idx = self.targets.index(engine)
             except ValueError:
                 pass # skip load-update for dead engines
             else:
                 if self.loads[idx] == self.hwm-1:
                     self.update_graph(None)
 
     def update_graph(self, dep_id=None, success=True):
         """dep_id just finished. Update our dependency
         graph and submit any jobs that just became runnable.
 
         Called with dep_id=None to update entire graph for hwm, but without finishing a task.
         """
         # print ("\n\n***********")
         # pprint (dep_id)
         # pprint (self.graph)
         # pprint (self.queue_map)
         # pprint (self.all_completed)
         # pprint (self.all_failed)
         # print ("\n\n***********\n\n")
         # update any jobs that depended on the dependency
         msg_ids = self.graph.pop(dep_id, [])
 
         # recheck *all* jobs if
         # a) we have HWM and an engine just become no longer full
         # or b) dep_id was given as None
         
         if dep_id is None or self.hwm and any( [ load==self.hwm-1 for load in self.loads ]):
             jobs = self.queue
             using_queue = True
         else:
             using_queue = False
             jobs = deque(sorted( self.queue_map[msg_id] for msg_id in msg_ids ))
         
         to_restore = []
         while jobs:
             job = jobs.popleft()
             if job.removed:
                 continue
             msg_id = job.msg_id
             
             put_it_back = True
             
             if job.after.unreachable(self.all_completed, self.all_failed)\
                     or job.follow.unreachable(self.all_completed, self.all_failed):
                 self.fail_unreachable(msg_id)
                 put_it_back = False
 
             elif job.after.check(self.all_completed, self.all_failed): # time deps met, maybe run
                 if self.maybe_run(job):
                     put_it_back = False
                     self.queue_map.pop(msg_id)
                     for mid in job.dependents:
                         if mid in self.graph:
                             self.graph[mid].remove(msg_id)
                     
                     # abort the loop if we just filled up all of our engines.
                     # avoids an O(N) operation in situation of full queue,
                     # where graph update is triggered as soon as an engine becomes
                     # non-full, and all tasks after the first are checked,
                     # even though they can't run.
                     if not self.available_engines():
                         break
             
             if using_queue and put_it_back:
                 # popped a job from the queue but it neither ran nor failed,
                 # so we need to put it back when we are done
                 # make sure to_restore preserves the same ordering
                 to_restore.append(job)
         
         # put back any tasks we popped but didn't run
         if using_queue:
             self.queue.extendleft(to_restore)
     
     #----------------------------------------------------------------------
     # methods to be overridden by subclasses
     #----------------------------------------------------------------------
 
     def add_job(self, idx):
         """Called after self.targets[idx] just got the job with header.
         Override with subclasses.  The default ordering is simple LRU.
         The default loads are the number of outstanding jobs."""
         self.loads[idx] += 1
         for lis in (self.targets, self.loads):
             lis.append(lis.pop(idx))
 
 
     def finish_job(self, idx):
         """Called after self.targets[idx] just finished a job.
         Override with subclasses."""
         self.loads[idx] -= 1
 
 
 
 def launch_scheduler(in_addr, out_addr, mon_addr, not_addr, reg_addr, config=None,
                         logname='root', log_url=None, loglevel=logging.DEBUG,
                         identity=b'task', in_thread=False):
 
     ZMQStream = zmqstream.ZMQStream
 
     if config:
         # unwrap dict back into Config
         config = Config(config)
 
     if in_thread:
         # use instance() to get the same Context/Loop as our parent
         ctx = zmq.Context.instance()
         loop = ioloop.IOLoop.instance()
     else:
         # in a process, don't use instance()
         # for safety with multiprocessing
         ctx = zmq.Context()
         loop = ioloop.IOLoop()
     ins = ZMQStream(ctx.socket(zmq.ROUTER),loop)
     util.set_hwm(ins, 0)
     ins.setsockopt(zmq.IDENTITY, identity + b'_in')
     ins.bind(in_addr)
 
     outs = ZMQStream(ctx.socket(zmq.ROUTER),loop)
     util.set_hwm(outs, 0)
     outs.setsockopt(zmq.IDENTITY, identity + b'_out')
     outs.bind(out_addr)
     mons = zmqstream.ZMQStream(ctx.socket(zmq.PUB),loop)
     util.set_hwm(mons, 0)
     mons.connect(mon_addr)
     nots = zmqstream.ZMQStream(ctx.socket(zmq.SUB),loop)
     nots.setsockopt(zmq.SUBSCRIBE, b'')
     nots.connect(not_addr)
     
     querys = ZMQStream(ctx.socket(zmq.DEALER),loop)
     querys.connect(reg_addr)
     
     # setup logging.
     if in_thread:
         log = Application.instance().log
     else:
         if log_url:
             log = connect_logger(logname, ctx, log_url, root="scheduler", loglevel=loglevel)
         else:
             log = local_logger(logname, loglevel)
 
     scheduler = TaskScheduler(client_stream=ins, engine_stream=outs,
                             mon_stream=mons, notifier_stream=nots,
                             query_stream=querys,
                             loop=loop, log=log,
                             config=config)
     scheduler.start()
     if not in_thread:
         try:
             loop.start()
         except KeyboardInterrupt:
             scheduler.log.critical("Interrupted, exiting...")
 

IPython/terminal/console/interactiveshell.py

@@ -1,578 +1,578 b''
 # -*- coding: utf-8 -*-
 """terminal client to the IPython kernel"""
 
 # Copyright (c) IPython Development Team.
 # Distributed under the terms of the Modified BSD License.
 
 from __future__ import print_function
 
 import base64
 import bdb
 import signal
 import os
 import sys
 import time
 import subprocess
 from getpass import getpass
 from io import BytesIO
 
 try:
     from queue import Empty  # Py 3
 except ImportError:
     from Queue import Empty  # Py 2
 
 from IPython.core import page
 from IPython.core import release
 from IPython.terminal.console.zmqhistory import ZMQHistoryManager
 from IPython.utils.warn import warn, error
 from IPython.utils import io
 from IPython.utils.py3compat import string_types, input
 from IPython.utils.traitlets import List, Enum, Any, Instance, Unicode, Float, Bool
 from IPython.utils.tempdir import NamedFileInTemporaryDirectory
 
 from IPython.terminal.interactiveshell import TerminalInteractiveShell
 from IPython.terminal.console.completer import ZMQCompleter
 
 class ZMQTerminalInteractiveShell(TerminalInteractiveShell):
     """A subclass of TerminalInteractiveShell that uses the 0MQ kernel"""
     _executing = False
     _execution_state = Unicode('')
     _pending_clearoutput = False
     kernel_banner = Unicode('')
     kernel_timeout = Float(60, config=True,
         help="""Timeout for giving up on a kernel (in seconds).
         
         On first connect and restart, the console tests whether the
         kernel is running and responsive by sending kernel_info_requests.
         This sets the timeout in seconds for how long the kernel can take
         before being presumed dead.
         """
     )
 
     image_handler = Enum(('PIL', 'stream', 'tempfile', 'callable'),
-                         config=True, help=
+                         config=True, allow_none=True, help=
         """
         Handler for image type output.  This is useful, for example,
         when connecting to the kernel in which pylab inline backend is
         activated.  There are four handlers defined.  'PIL': Use
         Python Imaging Library to popup image; 'stream': Use an
         external program to show the image.  Image will be fed into
         the STDIN of the program.  You will need to configure
         `stream_image_handler`; 'tempfile': Use an external program to
         show the image.  Image will be saved in a temporally file and
         the program is called with the temporally file.  You will need
         to configure `tempfile_image_handler`; 'callable': You can set
         any Python callable which is called with the image data.  You
         will need to configure `callable_image_handler`.
         """
     )
 
     stream_image_handler = List(config=True, help=
         """
         Command to invoke an image viewer program when you are using
         'stream' image handler.  This option is a list of string where
         the first element is the command itself and reminders are the
         options for the command.  Raw image data is given as STDIN to
         the program.
         """
     )
 
     tempfile_image_handler = List(config=True, help=
         """
         Command to invoke an image viewer program when you are using
         'tempfile' image handler.  This option is a list of string
         where the first element is the command itself and reminders
         are the options for the command.  You can use {file} and
         {format} in the string to represent the location of the
         generated image file and image format.
         """
     )
 
     callable_image_handler = Any(config=True, help=
         """
         Callable object called via 'callable' image handler with one
         argument, `data`, which is `msg["content"]["data"]` where
         `msg` is the message from iopub channel.  For exmaple, you can
         find base64 encoded PNG data as `data['image/png']`.
         """
     )
 
     mime_preference = List(
         default_value=['image/png', 'image/jpeg', 'image/svg+xml'],
-        config=True, allow_none=False, help=
+        config=True, help=
         """
         Preferred object representation MIME type in order.  First
         matched MIME type will be used.
         """
     )
 
     manager = Instance('IPython.kernel.KernelManager')
     client = Instance('IPython.kernel.KernelClient')
     def _client_changed(self, name, old, new):
         self.session_id = new.session.session
     session_id = Unicode()
 
     def init_completer(self):
         """Initialize the completion machinery.
 
         This creates completion machinery that can be used by client code,
         either interactively in-process (typically triggered by the readline
         library), programmatically (such as in test suites) or out-of-process
         (typically over the network by remote frontends).
         """
         from IPython.core.completerlib import (module_completer,
                                                magic_run_completer, cd_completer)
         
         self.Completer = ZMQCompleter(self, self.client, config=self.config)
         
 
         self.set_hook('complete_command', module_completer, str_key = 'import')
         self.set_hook('complete_command', module_completer, str_key = 'from')
         self.set_hook('complete_command', magic_run_completer, str_key = '%run')
         self.set_hook('complete_command', cd_completer, str_key = '%cd')
 
         # Only configure readline if we truly are using readline.  IPython can
         # do tab-completion over the network, in GUIs, etc, where readline
         # itself may be absent
         if self.has_readline:
             self.set_readline_completer()
     
     def run_cell(self, cell, store_history=True):
         """Run a complete IPython cell.
         
         Parameters
         ----------
         cell : str
           The code (including IPython code such as %magic functions) to run.
         store_history : bool
           If True, the raw and translated cell will be stored in IPython's
           history. For user code calling back into IPython's machinery, this
           should be set to False.
         """
         if (not cell) or cell.isspace():
             # pressing enter flushes any pending display
             self.handle_iopub()
             return
         
         # flush stale replies, which could have been ignored, due to missed heartbeats
         while self.client.shell_channel.msg_ready():
             self.client.shell_channel.get_msg()
         # execute takes 'hidden', which is the inverse of store_hist
         msg_id = self.client.execute(cell, not store_history)
         
         # first thing is wait for any side effects (output, stdin, etc.)
         self._executing = True
         self._execution_state = "busy"
         while self._execution_state != 'idle' and self.client.is_alive():
             try:
                 self.handle_input_request(msg_id, timeout=0.05)
             except Empty:
                 # display intermediate print statements, etc.
                 self.handle_iopub(msg_id)
         
         # after all of that is done, wait for the execute reply
         while self.client.is_alive():
             try:
                 self.handle_execute_reply(msg_id, timeout=0.05)
             except Empty:
                 pass
             else:
                 break
         self._executing = False
 
     #-----------------
     # message handlers
     #-----------------
 
     def handle_execute_reply(self, msg_id, timeout=None):
         msg = self.client.shell_channel.get_msg(block=False, timeout=timeout)
         if msg["parent_header"].get("msg_id", None) == msg_id:
             
             self.handle_iopub(msg_id)
             
             content = msg["content"]
             status = content['status']
             
             if status == 'aborted':
                 self.write('Aborted\n')
                 return
             elif status == 'ok':
                 # handle payloads
                 for item in content["payload"]:
                     source = item['source']
                     if source == 'page':
                         page.page(item['data']['text/plain'])
                     elif source == 'set_next_input':
                         self.set_next_input(item['text'])
                     elif source == 'ask_exit':
                         self.ask_exit()
                
             elif status == 'error':
                 for frame in content["traceback"]:
                     print(frame, file=io.stderr)
             
             self.execution_count = int(content["execution_count"] + 1)
     
     include_other_output = Bool(False, config=True,
         help="""Whether to include output from clients
         other than this one sharing the same kernel.
         
         Outputs are not displayed until enter is pressed.
         """
     )
     other_output_prefix = Unicode("[remote] ", config=True,
         help="""Prefix to add to outputs coming from clients other than this one.
         
         Only relevant if include_other_output is True.
         """
     )
     
     def from_here(self, msg):
         """Return whether a message is from this session"""
         return msg['parent_header'].get("session", self.session_id) == self.session_id
     
     def include_output(self, msg):
         """Return whether we should include a given output message"""
         from_here = self.from_here(msg)
         if msg['msg_type'] == 'execute_input':
             # only echo inputs not from here
             return self.include_other_output and not from_here
         
         if self.include_other_output:
             return True
         else:
             return from_here
     
     def handle_iopub(self, msg_id=''):
         """Process messages on the IOPub channel
 
            This method consumes and processes messages on the IOPub channel,
            such as stdout, stderr, execute_result and status.
            
            It only displays output that is caused by this session.
         """
         while self.client.iopub_channel.msg_ready():
             sub_msg = self.client.iopub_channel.get_msg()
             msg_type = sub_msg['header']['msg_type']
             parent = sub_msg["parent_header"]
             
             if self.include_output(sub_msg):
                 if msg_type == 'status':
                     self._execution_state = sub_msg["content"]["execution_state"]
                 elif msg_type == 'stream':
                     if sub_msg["content"]["name"] == "stdout":
                         if self._pending_clearoutput:
                             print("\r", file=io.stdout, end="")
                             self._pending_clearoutput = False
                         print(sub_msg["content"]["text"], file=io.stdout, end="")
                         io.stdout.flush()
                     elif sub_msg["content"]["name"] == "stderr":
                         if self._pending_clearoutput:
                             print("\r", file=io.stderr, end="")
                             self._pending_clearoutput = False
                         print(sub_msg["content"]["text"], file=io.stderr, end="")
                         io.stderr.flush()
 
                 elif msg_type == 'execute_result':
                     if self._pending_clearoutput:
                         print("\r", file=io.stdout, end="")
                         self._pending_clearoutput = False
                     self.execution_count = int(sub_msg["content"]["execution_count"])
                     if not self.from_here(sub_msg):
                         sys.stdout.write(self.other_output_prefix)
                     format_dict = sub_msg["content"]["data"]
                     self.handle_rich_data(format_dict)
                     
                     # taken from DisplayHook.__call__:
                     hook = self.displayhook
                     hook.start_displayhook()
                     hook.write_output_prompt()
                     hook.write_format_data(format_dict)
                     hook.log_output(format_dict)
                     hook.finish_displayhook()
 
                 elif msg_type == 'display_data':
                     data = sub_msg["content"]["data"]
                     handled = self.handle_rich_data(data)
                     if not handled:
                         if not self.from_here(sub_msg):
                             sys.stdout.write(self.other_output_prefix)
                         # if it was an image, we handled it by now
                         if 'text/plain' in data:
                             print(data['text/plain'])
                 
                 elif msg_type == 'execute_input':
                     content = sub_msg['content']
                     self.execution_count = content['execution_count']
                     if not self.from_here(sub_msg):
                         sys.stdout.write(self.other_output_prefix)
                     sys.stdout.write(self.prompt_manager.render('in'))
                     sys.stdout.write(content['code'])
                 
                 elif msg_type == 'clear_output':
                     if sub_msg["content"]["wait"]:
                         self._pending_clearoutput = True
                     else:
                         print("\r", file=io.stdout, end="")
 
     _imagemime = {
         'image/png': 'png',
         'image/jpeg': 'jpeg',
         'image/svg+xml': 'svg',
     }
 
     def handle_rich_data(self, data):
         for mime in self.mime_preference:
             if mime in data and mime in self._imagemime:
                 self.handle_image(data, mime)
                 return True
 
     def handle_image(self, data, mime):
         handler = getattr(
             self, 'handle_image_{0}'.format(self.image_handler), None)
         if handler:
             handler(data, mime)
 
     def handle_image_PIL(self, data, mime):
         if mime not in ('image/png', 'image/jpeg'):
             return
         import PIL.Image
         raw = base64.decodestring(data[mime].encode('ascii'))
         img = PIL.Image.open(BytesIO(raw))
         img.show()
 
     def handle_image_stream(self, data, mime):
         raw = base64.decodestring(data[mime].encode('ascii'))
         imageformat = self._imagemime[mime]
         fmt = dict(format=imageformat)
         args = [s.format(**fmt) for s in self.stream_image_handler]
         with open(os.devnull, 'w') as devnull:
             proc = subprocess.Popen(
                 args, stdin=subprocess.PIPE,
                 stdout=devnull, stderr=devnull)
             proc.communicate(raw)
 
     def handle_image_tempfile(self, data, mime):
         raw = base64.decodestring(data[mime].encode('ascii'))
         imageformat = self._imagemime[mime]
         filename = 'tmp.{0}'.format(imageformat)
         with NamedFileInTemporaryDirectory(filename) as f, \
                     open(os.devnull, 'w') as devnull:
             f.write(raw)
             f.flush()
             fmt = dict(file=f.name, format=imageformat)
             args = [s.format(**fmt) for s in self.tempfile_image_handler]
             subprocess.call(args, stdout=devnull, stderr=devnull)
 
     def handle_image_callable(self, data, mime):
         self.callable_image_handler(data)
 
     def handle_input_request(self, msg_id, timeout=0.1):
         """ Method to capture raw_input
         """
         req = self.client.stdin_channel.get_msg(timeout=timeout)
         # in case any iopub came while we were waiting:
         self.handle_iopub(msg_id)
         if msg_id == req["parent_header"].get("msg_id"):
             # wrap SIGINT handler
             real_handler = signal.getsignal(signal.SIGINT)
             def double_int(sig,frame):
                 # call real handler (forwards sigint to kernel),
                 # then raise local interrupt, stopping local raw_input
                 real_handler(sig,frame)
                 raise KeyboardInterrupt
             signal.signal(signal.SIGINT, double_int)
             content = req['content']
             read = getpass if content.get('password', False) else input
             try:
                 raw_data = read(content["prompt"])
             except EOFError:
                 # turn EOFError into EOF character
                 raw_data = '\x04'
             except KeyboardInterrupt:
                 sys.stdout.write('\n')
                 return
             finally:
                 # restore SIGINT handler
                 signal.signal(signal.SIGINT, real_handler)
             
             # only send stdin reply if there *was not* another request
             # or execution finished while we were reading.
             if not (self.client.stdin_channel.msg_ready() or self.client.shell_channel.msg_ready()):
                 self.client.input(raw_data)
 
     def mainloop(self, display_banner=False):
         while True:
             try:
                 self.interact(display_banner=display_banner)
                 #self.interact_with_readline()
                 # XXX for testing of a readline-decoupled repl loop, call
                 # interact_with_readline above
                 break
             except KeyboardInterrupt:
                 # this should not be necessary, but KeyboardInterrupt
                 # handling seems rather unpredictable...
                 self.write("\nKeyboardInterrupt in interact()\n")
 
         self.client.shutdown()
     
     def _banner1_default(self):
         return "IPython Console {version}\n".format(version=release.version)
     
     def compute_banner(self):
         super(ZMQTerminalInteractiveShell, self).compute_banner()
         if self.client and not self.kernel_banner:
             msg_id = self.client.kernel_info()
             while True:
                 try:
                     reply = self.client.get_shell_msg(timeout=1)
                 except Empty:
                     break
                 else:
                     if reply['parent_header'].get('msg_id') == msg_id:
                         self.kernel_banner = reply['content'].get('banner', '')
                         break
         self.banner += self.kernel_banner
     
     def wait_for_kernel(self, timeout=None):
         """method to wait for a kernel to be ready"""
         tic = time.time()
         self.client.hb_channel.unpause()
         while True:
             msg_id = self.client.kernel_info()
             reply = None
             while True:
                 try:
                     reply = self.client.get_shell_msg(timeout=1)
                 except Empty:
                     break
                 else:
                     if reply['parent_header'].get('msg_id') == msg_id:
                         return True
             if timeout is not None \
                 and (time.time() - tic) > timeout \
                 and not self.client.hb_channel.is_beating():
                 # heart failed
                 return False
         return True
     
     def interact(self, display_banner=None):
         """Closely emulate the interactive Python console."""
 
         # batch run -> do not interact
         if self.exit_now:
             return
 
         if display_banner is None:
             display_banner = self.display_banner
         
         if isinstance(display_banner, string_types):
             self.show_banner(display_banner)
         elif display_banner:
             self.show_banner()
 
         more = False
         
         # run a non-empty no-op, so that we don't get a prompt until
         # we know the kernel is ready. This keeps the connection
         # message above the first prompt.
         if not self.wait_for_kernel(self.kernel_timeout):
             error("Kernel did not respond\n")
             return
         
         if self.has_readline:
             self.readline_startup_hook(self.pre_readline)
             hlen_b4_cell = self.readline.get_current_history_length()
         else:
             hlen_b4_cell = 0
         # exit_now is set by a call to %Exit or %Quit, through the
         # ask_exit callback.
 
         while not self.exit_now:
             if not self.client.is_alive():
                 # kernel died, prompt for action or exit
 
                 action = "restart" if self.manager else "wait for restart"
                 ans = self.ask_yes_no("kernel died, %s ([y]/n)?" % action, default='y')
                 if ans:
                     if self.manager:
                         self.manager.restart_kernel(True)
                     self.wait_for_kernel(self.kernel_timeout)
                 else:
                     self.exit_now = True
                 continue
             try:
                 # protect prompt block from KeyboardInterrupt
                 # when sitting on ctrl-C
                 self.hooks.pre_prompt_hook()
                 if more:
                     try:
                         prompt = self.prompt_manager.render('in2')
                     except Exception:
                         self.showtraceback()
                     if self.autoindent:
                         self.rl_do_indent = True
                     
                 else:
                     try:
                         prompt = self.separate_in + self.prompt_manager.render('in')
                     except Exception:
                         self.showtraceback()
                 
                 line = self.raw_input(prompt)
                 if self.exit_now:
                     # quick exit on sys.std[in|out] close
                     break
                 if self.autoindent:
                     self.rl_do_indent = False
                     
             except KeyboardInterrupt:
                 #double-guard against keyboardinterrupts during kbdint handling
                 try:
                     self.write('\n' + self.get_exception_only())
                     source_raw = self.input_splitter.raw_reset()
                     hlen_b4_cell = self._replace_rlhist_multiline(source_raw, hlen_b4_cell)
                     more = False
                 except KeyboardInterrupt:
                     pass
             except EOFError:
                 if self.autoindent:
                     self.rl_do_indent = False
                     if self.has_readline:
                         self.readline_startup_hook(None)
                 self.write('\n')
                 self.exit()
             except bdb.BdbQuit:
                 warn('The Python debugger has exited with a BdbQuit exception.\n'
                      'Because of how pdb handles the stack, it is impossible\n'
                      'for IPython to properly format this particular exception.\n'
                      'IPython will resume normal operation.')
             except:
                 # exceptions here are VERY RARE, but they can be triggered
                 # asynchronously by signal handlers, for example.
                 self.showtraceback()
             else:
                 try:
                     self.input_splitter.push(line)
                     more = self.input_splitter.push_accepts_more()
                 except SyntaxError:
                     # Run the code directly - run_cell takes care of displaying
                     # the exception.
                     more = False
                 if (self.SyntaxTB.last_syntax_error and
                     self.autoedit_syntax):
                     self.edit_syntax_error()
                 if not more:
                     source_raw = self.input_splitter.raw_reset()
                     hlen_b4_cell = self._replace_rlhist_multiline(source_raw, hlen_b4_cell)
                     self.run_cell(source_raw)
                 
 
         # Turn off the exit flag, so the mainloop can be restarted if desired
         self.exit_now = False
 
     def init_history(self):
         """Sets up the command history. """
         self.history_manager = ZMQHistoryManager(client=self.client) 
         self.configurables.append(self.history_manager)
 

IPython/utils/tests/test_traitlets.py

@@ -1,1468 +1,1468 b''
 # encoding: utf-8
 """Tests for IPython.utils.traitlets."""
 
 # Copyright (c) IPython Development Team.
 # Distributed under the terms of the Modified BSD License.
 # 
 # Adapted from enthought.traits, Copyright (c) Enthought, Inc.,
 # also under the terms of the Modified BSD License.
 
 import pickle
 import re
 import sys
 from unittest import TestCase
 
 import nose.tools as nt
 from nose import SkipTest
 
 from IPython.utils.traitlets import (
     HasTraits, MetaHasTraits, TraitType, Any, Bool, CBytes, Dict, Enum,
     Int, Long, Integer, Float, Complex, Bytes, Unicode, TraitError,
     Union, Undefined, Type, This, Instance, TCPAddress, List, Tuple,
     ObjectName, DottedObjectName, CRegExp, link, directional_link,
     EventfulList, EventfulDict, ForwardDeclaredType, ForwardDeclaredInstance,
 )
 from IPython.utils import py3compat
 from IPython.testing.decorators import skipif
 
 #-----------------------------------------------------------------------------
 # Helper classes for testing
 #-----------------------------------------------------------------------------
 
 
 class HasTraitsStub(HasTraits):
 
     def _notify_trait(self, name, old, new):
         self._notify_name = name
         self._notify_old = old
         self._notify_new = new
 
 
 #-----------------------------------------------------------------------------
 # Test classes
 #-----------------------------------------------------------------------------
 
 
 class TestTraitType(TestCase):
 
     def test_get_undefined(self):
         class A(HasTraits):
             a = TraitType
         a = A()
         self.assertEqual(a.a, Undefined)
 
     def test_set(self):
         class A(HasTraitsStub):
             a = TraitType
 
         a = A()
         a.a = 10
         self.assertEqual(a.a, 10)
         self.assertEqual(a._notify_name, 'a')
         self.assertEqual(a._notify_old, Undefined)
         self.assertEqual(a._notify_new, 10)
 
     def test_validate(self):
         class MyTT(TraitType):
             def validate(self, inst, value):
                 return -1
         class A(HasTraitsStub):
             tt = MyTT
 
         a = A()
         a.tt = 10
         self.assertEqual(a.tt, -1)
 
     def test_default_validate(self):
         class MyIntTT(TraitType):
             def validate(self, obj, value):
                 if isinstance(value, int):
                     return value
                 self.error(obj, value)
         class A(HasTraits):
             tt = MyIntTT(10)
         a = A()
         self.assertEqual(a.tt, 10)
 
         # Defaults are validated when the HasTraits is instantiated
         class B(HasTraits):
             tt = MyIntTT('bad default')
         self.assertRaises(TraitError, B)
 
     def test_info(self):
         class A(HasTraits):
             tt = TraitType
         a = A()
         self.assertEqual(A.tt.info(), 'any value')
 
     def test_error(self):
         class A(HasTraits):
             tt = TraitType
         a = A()
         self.assertRaises(TraitError, A.tt.error, a, 10)
 
     def test_dynamic_initializer(self):
         class A(HasTraits):
             x = Int(10)
             def _x_default(self):
                 return 11
         class B(A):
             x = Int(20)
         class C(A):
             def _x_default(self):
                 return 21
 
         a = A()
         self.assertEqual(a._trait_values, {})
         self.assertEqual(list(a._trait_dyn_inits.keys()), ['x'])
         self.assertEqual(a.x, 11)
         self.assertEqual(a._trait_values, {'x': 11})
         b = B()
         self.assertEqual(b._trait_values, {'x': 20})
         self.assertEqual(list(a._trait_dyn_inits.keys()), ['x'])
         self.assertEqual(b.x, 20)
         c = C()
         self.assertEqual(c._trait_values, {})
         self.assertEqual(list(a._trait_dyn_inits.keys()), ['x'])
         self.assertEqual(c.x, 21)
         self.assertEqual(c._trait_values, {'x': 21})
         # Ensure that the base class remains unmolested when the _default
         # initializer gets overridden in a subclass.
         a = A()
         c = C()
         self.assertEqual(a._trait_values, {})
         self.assertEqual(list(a._trait_dyn_inits.keys()), ['x'])
         self.assertEqual(a.x, 11)
         self.assertEqual(a._trait_values, {'x': 11})
 
 
 
 class TestHasTraitsMeta(TestCase):
 
     def test_metaclass(self):
         self.assertEqual(type(HasTraits), MetaHasTraits)
 
         class A(HasTraits):
             a = Int
 
         a = A()
         self.assertEqual(type(a.__class__), MetaHasTraits)
         self.assertEqual(a.a,0)
         a.a = 10
         self.assertEqual(a.a,10)
 
         class B(HasTraits):
             b = Int()
 
         b = B()
         self.assertEqual(b.b,0)
         b.b = 10
         self.assertEqual(b.b,10)
 
         class C(HasTraits):
             c = Int(30)
 
         c = C()
         self.assertEqual(c.c,30)
         c.c = 10
         self.assertEqual(c.c,10)
 
     def test_this_class(self):
         class A(HasTraits):
             t = This()
             tt = This()
         class B(A):
             tt = This()
             ttt = This()
         self.assertEqual(A.t.this_class, A)
         self.assertEqual(B.t.this_class, A)
         self.assertEqual(B.tt.this_class, B)
         self.assertEqual(B.ttt.this_class, B)
 
 class TestHasTraitsNotify(TestCase):
 
     def setUp(self):
         self._notify1 = []
         self._notify2 = []
 
     def notify1(self, name, old, new):
         self._notify1.append((name, old, new))
 
     def notify2(self, name, old, new):
         self._notify2.append((name, old, new))
 
     def test_notify_all(self):
 
         class A(HasTraits):
             a = Int
             b = Float
 
         a = A()
         a.on_trait_change(self.notify1)
         a.a = 0
         self.assertEqual(len(self._notify1),0)
         a.b = 0.0
         self.assertEqual(len(self._notify1),0)
         a.a = 10
         self.assertTrue(('a',0,10) in self._notify1)
         a.b = 10.0
         self.assertTrue(('b',0.0,10.0) in self._notify1)
         self.assertRaises(TraitError,setattr,a,'a','bad string')
         self.assertRaises(TraitError,setattr,a,'b','bad string')
         self._notify1 = []
         a.on_trait_change(self.notify1,remove=True)
         a.a = 20
         a.b = 20.0
         self.assertEqual(len(self._notify1),0)
 
     def test_notify_one(self):
 
         class A(HasTraits):
             a = Int
             b = Float
 
         a = A()
         a.on_trait_change(self.notify1, 'a')
         a.a = 0
         self.assertEqual(len(self._notify1),0)
         a.a = 10
         self.assertTrue(('a',0,10) in self._notify1)
         self.assertRaises(TraitError,setattr,a,'a','bad string')
 
     def test_subclass(self):
 
         class A(HasTraits):
             a = Int
 
         class B(A):
             b = Float
 
         b = B()
         self.assertEqual(b.a,0)
         self.assertEqual(b.b,0.0)
         b.a = 100
         b.b = 100.0
         self.assertEqual(b.a,100)
         self.assertEqual(b.b,100.0)
 
     def test_notify_subclass(self):
 
         class A(HasTraits):
             a = Int
 
         class B(A):
             b = Float
 
         b = B()
         b.on_trait_change(self.notify1, 'a')
         b.on_trait_change(self.notify2, 'b')
         b.a = 0
         b.b = 0.0
         self.assertEqual(len(self._notify1),0)
         self.assertEqual(len(self._notify2),0)
         b.a = 10
         b.b = 10.0
         self.assertTrue(('a',0,10) in self._notify1)
         self.assertTrue(('b',0.0,10.0) in self._notify2)
 
     def test_static_notify(self):
 
         class A(HasTraits):
             a = Int
             _notify1 = []
             def _a_changed(self, name, old, new):
                 self._notify1.append((name, old, new))
 
         a = A()
         a.a = 0
         # This is broken!!!
         self.assertEqual(len(a._notify1),0)
         a.a = 10
         self.assertTrue(('a',0,10) in a._notify1)
 
         class B(A):
             b = Float
             _notify2 = []
             def _b_changed(self, name, old, new):
                 self._notify2.append((name, old, new))
 
         b = B()
         b.a = 10
         b.b = 10.0
         self.assertTrue(('a',0,10) in b._notify1)
         self.assertTrue(('b',0.0,10.0) in b._notify2)
 
     def test_notify_args(self):
 
         def callback0():
             self.cb = ()
         def callback1(name):
             self.cb = (name,)
         def callback2(name, new):
             self.cb = (name, new)
         def callback3(name, old, new):
             self.cb = (name, old, new)
 
         class A(HasTraits):
             a = Int
 
         a = A()
         a.on_trait_change(callback0, 'a')
         a.a = 10
         self.assertEqual(self.cb,())
         a.on_trait_change(callback0, 'a', remove=True)
 
         a.on_trait_change(callback1, 'a')
         a.a = 100
         self.assertEqual(self.cb,('a',))
         a.on_trait_change(callback1, 'a', remove=True)
 
         a.on_trait_change(callback2, 'a')
         a.a = 1000
         self.assertEqual(self.cb,('a',1000))
         a.on_trait_change(callback2, 'a', remove=True)
 
         a.on_trait_change(callback3, 'a')
         a.a = 10000
         self.assertEqual(self.cb,('a',1000,10000))
         a.on_trait_change(callback3, 'a', remove=True)
 
         self.assertEqual(len(a._trait_notifiers['a']),0)
 
     def test_notify_only_once(self):
 
         class A(HasTraits):
             listen_to = ['a']
             
             a = Int(0)
             b = 0
             
             def __init__(self, **kwargs):
                 super(A, self).__init__(**kwargs)
                 self.on_trait_change(self.listener1, ['a'])
             
             def listener1(self, name, old, new):
                 self.b += 1
 
         class B(A):
                     
             c = 0
             d = 0
             
             def __init__(self, **kwargs):
                 super(B, self).__init__(**kwargs)
                 self.on_trait_change(self.listener2)
             
             def listener2(self, name, old, new):
                 self.c += 1
             
             def _a_changed(self, name, old, new):
                 self.d += 1
 
         b = B()
         b.a += 1
         self.assertEqual(b.b, b.c)
         self.assertEqual(b.b, b.d)
         b.a += 1
         self.assertEqual(b.b, b.c)
         self.assertEqual(b.b, b.d)
 
 
 class TestHasTraits(TestCase):
 
     def test_trait_names(self):
         class A(HasTraits):
             i = Int
             f = Float
         a = A()
         self.assertEqual(sorted(a.trait_names()),['f','i'])
         self.assertEqual(sorted(A.class_trait_names()),['f','i'])
 
     def test_trait_metadata(self):
         class A(HasTraits):
             i = Int(config_key='MY_VALUE')
         a = A()
         self.assertEqual(a.trait_metadata('i','config_key'), 'MY_VALUE')
 
     def test_trait_metadata_default(self):
         class A(HasTraits):
             i = Int()
         a = A()
         self.assertEqual(a.trait_metadata('i', 'config_key'), None)
         self.assertEqual(a.trait_metadata('i', 'config_key', 'default'), 'default')
 
     def test_traits(self):
         class A(HasTraits):
             i = Int
             f = Float
         a = A()
         self.assertEqual(a.traits(), dict(i=A.i, f=A.f))
         self.assertEqual(A.class_traits(), dict(i=A.i, f=A.f))
 
     def test_traits_metadata(self):
         class A(HasTraits):
             i = Int(config_key='VALUE1', other_thing='VALUE2')
             f = Float(config_key='VALUE3', other_thing='VALUE2')
             j = Int(0)
         a = A()
         self.assertEqual(a.traits(), dict(i=A.i, f=A.f, j=A.j))
         traits = a.traits(config_key='VALUE1', other_thing='VALUE2')
         self.assertEqual(traits, dict(i=A.i))
 
         # This passes, but it shouldn't because I am replicating a bug in
         # traits.
         traits = a.traits(config_key=lambda v: True)
         self.assertEqual(traits, dict(i=A.i, f=A.f, j=A.j))
 
     def test_init(self):
         class A(HasTraits):
             i = Int()
             x = Float()
         a = A(i=1, x=10.0)
         self.assertEqual(a.i, 1)
         self.assertEqual(a.x, 10.0)
 
     def test_positional_args(self):
         class A(HasTraits):
             i = Int(0)
             def __init__(self, i):
                 super(A, self).__init__()
                 self.i = i
         
         a = A(5)
         self.assertEqual(a.i, 5)
         # should raise TypeError if no positional arg given
         self.assertRaises(TypeError, A)
 
 #-----------------------------------------------------------------------------
 # Tests for specific trait types
 #-----------------------------------------------------------------------------
 
 
 class TestType(TestCase):
 
     def test_default(self):
 
         class B(object): pass
         class A(HasTraits):
             klass = Type
 
         a = A()
         self.assertEqual(a.klass, None)
 
         a.klass = B
         self.assertEqual(a.klass, B)
         self.assertRaises(TraitError, setattr, a, 'klass', 10)
 
     def test_value(self):
 
         class B(object): pass
         class C(object): pass
         class A(HasTraits):
             klass = Type(B)
 
         a = A()
         self.assertEqual(a.klass, B)
         self.assertRaises(TraitError, setattr, a, 'klass', C)
         self.assertRaises(TraitError, setattr, a, 'klass', object)
         a.klass = B
 
     def test_allow_none(self):
 
         class B(object): pass
         class C(B): pass
         class A(HasTraits):
             klass = Type(B, allow_none=False)
 
         a = A()
         self.assertEqual(a.klass, B)
         self.assertRaises(TraitError, setattr, a, 'klass', None)
         a.klass = C
         self.assertEqual(a.klass, C)
 
     def test_validate_klass(self):
 
         class A(HasTraits):
             klass = Type('no strings allowed')
 
         self.assertRaises(ImportError, A)
 
         class A(HasTraits):
             klass = Type('rub.adub.Duck')
 
         self.assertRaises(ImportError, A)
 
     def test_validate_default(self):
 
         class B(object): pass
         class A(HasTraits):
             klass = Type('bad default', B)
 
         self.assertRaises(ImportError, A)
 
         class C(HasTraits):
             klass = Type(None, B, allow_none=False)
 
         self.assertRaises(TraitError, C)
 
     def test_str_klass(self):
 
         class A(HasTraits):
             klass = Type('IPython.utils.ipstruct.Struct')
 
         from IPython.utils.ipstruct import Struct
         a = A()
         a.klass = Struct
         self.assertEqual(a.klass, Struct)
 
         self.assertRaises(TraitError, setattr, a, 'klass', 10)
 
     def test_set_str_klass(self):
 
         class A(HasTraits):
             klass = Type()
 
         a = A(klass='IPython.utils.ipstruct.Struct')
         from IPython.utils.ipstruct import Struct
         self.assertEqual(a.klass, Struct)
 
 class TestInstance(TestCase):
 
     def test_basic(self):
         class Foo(object): pass
         class Bar(Foo): pass
         class Bah(object): pass
 
         class A(HasTraits):
             inst = Instance(Foo)
 
         a = A()
         self.assertTrue(a.inst is None)
         a.inst = Foo()
         self.assertTrue(isinstance(a.inst, Foo))
         a.inst = Bar()
         self.assertTrue(isinstance(a.inst, Foo))
         self.assertRaises(TraitError, setattr, a, 'inst', Foo)
         self.assertRaises(TraitError, setattr, a, 'inst', Bar)
         self.assertRaises(TraitError, setattr, a, 'inst', Bah())
 
     def test_default_klass(self):
         class Foo(object): pass
         class Bar(Foo): pass
         class Bah(object): pass
 
         class FooInstance(Instance):
             klass = Foo
 
         class A(HasTraits):
             inst = FooInstance()
 
         a = A()
         self.assertTrue(a.inst is None)
         a.inst = Foo()
         self.assertTrue(isinstance(a.inst, Foo))
         a.inst = Bar()
         self.assertTrue(isinstance(a.inst, Foo))
         self.assertRaises(TraitError, setattr, a, 'inst', Foo)
         self.assertRaises(TraitError, setattr, a, 'inst', Bar)
         self.assertRaises(TraitError, setattr, a, 'inst', Bah())
 
     def test_unique_default_value(self):
         class Foo(object): pass
         class A(HasTraits):
             inst = Instance(Foo,(),{})
 
         a = A()
         b = A()
         self.assertTrue(a.inst is not b.inst)
 
     def test_args_kw(self):
         class Foo(object):
             def __init__(self, c): self.c = c
         class Bar(object): pass
         class Bah(object):
             def __init__(self, c, d):
                 self.c = c; self.d = d
 
         class A(HasTraits):
             inst = Instance(Foo, (10,))
         a = A()
         self.assertEqual(a.inst.c, 10)
 
         class B(HasTraits):
             inst = Instance(Bah, args=(10,), kw=dict(d=20))
         b = B()
         self.assertEqual(b.inst.c, 10)
         self.assertEqual(b.inst.d, 20)
 
         class C(HasTraits):
             inst = Instance(Foo)
         c = C()
         self.assertTrue(c.inst is None)
 
     def test_bad_default(self):
         class Foo(object): pass
 
         class A(HasTraits):
             inst = Instance(Foo, allow_none=False)
 
         self.assertRaises(TraitError, A)
 
     def test_instance(self):
         class Foo(object): pass
 
         def inner():
             class A(HasTraits):
                 inst = Instance(Foo())
 
         self.assertRaises(TraitError, inner)
 
 
 class TestThis(TestCase):
 
     def test_this_class(self):
         class Foo(HasTraits):
             this = This
 
         f = Foo()
         self.assertEqual(f.this, None)
         g = Foo()
         f.this = g
         self.assertEqual(f.this, g)
         self.assertRaises(TraitError, setattr, f, 'this', 10)
 
     def test_this_inst(self):
         class Foo(HasTraits):
             this = This()
 
         f = Foo()
         f.this = Foo()
         self.assertTrue(isinstance(f.this, Foo))
 
     def test_subclass(self):
         class Foo(HasTraits):
             t = This()
         class Bar(Foo):
             pass
         f = Foo()
         b = Bar()
         f.t = b
         b.t = f
         self.assertEqual(f.t, b)
         self.assertEqual(b.t, f)
 
     def test_subclass_override(self):
         class Foo(HasTraits):
             t = This()
         class Bar(Foo):
             t = This()
         f = Foo()
         b = Bar()
         f.t = b
         self.assertEqual(f.t, b)
         self.assertRaises(TraitError, setattr, b, 't', f)
 
     def test_this_in_container(self):
 
         class Tree(HasTraits):
             value = Unicode()
             leaves = List(This())
 
         tree = Tree(
             value='foo',
             leaves=[Tree('bar'), Tree('buzz')]
         )
 
         with self.assertRaises(TraitError):
             tree.leaves = [1, 2]
 
 class TraitTestBase(TestCase):
     """A best testing class for basic trait types."""
 
     def assign(self, value):
         self.obj.value = value
 
     def coerce(self, value):
         return value
 
     def test_good_values(self):
         if hasattr(self, '_good_values'):
             for value in self._good_values:
                 self.assign(value)
                 self.assertEqual(self.obj.value, self.coerce(value))
 
     def test_bad_values(self):
         if hasattr(self, '_bad_values'):
             for value in self._bad_values:
                 try:
                     self.assertRaises(TraitError, self.assign, value)
                 except AssertionError:
                     assert False, value
 
     def test_default_value(self):
         if hasattr(self, '_default_value'):
             self.assertEqual(self._default_value, self.obj.value)
 
     def test_allow_none(self):
         if (hasattr(self, '_bad_values') and hasattr(self, '_good_values') and
         None in self._bad_values):
             trait=self.obj.traits()['value']
             try:
                 trait.allow_none = True
                 self._bad_values.remove(None)
                 #skip coerce. Allow None casts None to None.
                 self.assign(None)
                 self.assertEqual(self.obj.value,None)
                 self.test_good_values()
                 self.test_bad_values()
             finally:
                 #tear down
                 trait.allow_none = False
                 self._bad_values.append(None)
 
     def tearDown(self):
         # restore default value after tests, if set
         if hasattr(self, '_default_value'):
             self.obj.value = self._default_value
 
 
 class AnyTrait(HasTraits):
 
     value = Any
 
 class AnyTraitTest(TraitTestBase):
 
     obj = AnyTrait()
 
     _default_value = None
     _good_values   = [10.0, 'ten', u'ten', [10], {'ten': 10},(10,), None, 1j]
     _bad_values    = []
 
 class UnionTrait(HasTraits):
 
     value = Union([Type(), Bool()])
 
 class UnionTraitTest(TraitTestBase):
 
     obj = UnionTrait(value='IPython.utils.ipstruct.Struct')
     _good_values = [int, float, True]
     _bad_values = [[], (0,), 1j]
 
 class OrTrait(HasTraits):
 
     value = Bool() | Unicode()
 
 class OrTraitTest(TraitTestBase):
 
     obj = OrTrait()
     _good_values = [True, False, 'ten']
     _bad_values = [[], (0,), 1j]
 
 class IntTrait(HasTraits):
 
     value = Int(99)
 
 class TestInt(TraitTestBase):
 
     obj = IntTrait()
     _default_value = 99
     _good_values   = [10, -10]
     _bad_values    = ['ten', u'ten', [10], {'ten': 10},(10,), None, 1j,
                       10.1, -10.1, '10L', '-10L', '10.1', '-10.1', u'10L',
                       u'-10L', u'10.1', u'-10.1',  '10', '-10', u'10', u'-10']
     if not py3compat.PY3:
         _bad_values.extend([long(10), long(-10), 10*sys.maxint, -10*sys.maxint])
 
 
 class LongTrait(HasTraits):
 
     value = Long(99 if py3compat.PY3 else long(99))
 
 class TestLong(TraitTestBase):
 
     obj = LongTrait()
 
     _default_value = 99 if py3compat.PY3 else long(99)
     _good_values   = [10, -10]
     _bad_values    = ['ten', u'ten', [10], {'ten': 10},(10,),
                       None, 1j, 10.1, -10.1, '10', '-10', '10L', '-10L', '10.1',
                       '-10.1', u'10', u'-10', u'10L', u'-10L', u'10.1',
                       u'-10.1']
     if not py3compat.PY3:
         # maxint undefined on py3, because int == long
         _good_values.extend([long(10), long(-10), 10*sys.maxint, -10*sys.maxint])
         _bad_values.extend([[long(10)], (long(10),)])
 
     @skipif(py3compat.PY3, "not relevant on py3")
     def test_cast_small(self):
         """Long casts ints to long"""
         self.obj.value = 10
         self.assertEqual(type(self.obj.value), long)
 
 
 class IntegerTrait(HasTraits):
     value = Integer(1)
 
 class TestInteger(TestLong):
     obj = IntegerTrait()
     _default_value = 1
 
     def coerce(self, n):
         return int(n)
 
     @skipif(py3compat.PY3, "not relevant on py3")
     def test_cast_small(self):
         """Integer casts small longs to int"""
         if py3compat.PY3:
             raise SkipTest("not relevant on py3")
 
         self.obj.value = long(100)
         self.assertEqual(type(self.obj.value), int)
 
 
 class FloatTrait(HasTraits):
 
     value = Float(99.0)
 
 class TestFloat(TraitTestBase):
 
     obj = FloatTrait()
 
     _default_value = 99.0
     _good_values   = [10, -10, 10.1, -10.1]
     _bad_values    = ['ten', u'ten', [10], {'ten': 10},(10,), None,
                       1j, '10', '-10', '10L', '-10L', '10.1', '-10.1', u'10',
                       u'-10', u'10L', u'-10L', u'10.1', u'-10.1']
     if not py3compat.PY3:
         _bad_values.extend([long(10), long(-10)])
 
 
 class ComplexTrait(HasTraits):
 
     value = Complex(99.0-99.0j)
 
 class TestComplex(TraitTestBase):
 
     obj = ComplexTrait()
 
     _default_value = 99.0-99.0j
     _good_values   = [10, -10, 10.1, -10.1, 10j, 10+10j, 10-10j,
                       10.1j, 10.1+10.1j, 10.1-10.1j]
     _bad_values    = [u'10L', u'-10L', 'ten', [10], {'ten': 10},(10,), None]
     if not py3compat.PY3:
         _bad_values.extend([long(10), long(-10)])
 
 
 class BytesTrait(HasTraits):
 
     value = Bytes(b'string')
 
 class TestBytes(TraitTestBase):
 
     obj = BytesTrait()
 
     _default_value = b'string'
     _good_values   = [b'10', b'-10', b'10L',
                       b'-10L', b'10.1', b'-10.1', b'string']
     _bad_values    = [10, -10, 10.1, -10.1, 1j, [10],
                       ['ten'],{'ten': 10},(10,), None,  u'string']
     if not py3compat.PY3:
         _bad_values.extend([long(10), long(-10)])
 
 
 class UnicodeTrait(HasTraits):
 
     value = Unicode(u'unicode')
 
 class TestUnicode(TraitTestBase):
 
     obj = UnicodeTrait()
 
     _default_value = u'unicode'
     _good_values   = ['10', '-10', '10L', '-10L', '10.1',
                       '-10.1', '', u'', 'string', u'string', u"€"]
     _bad_values    = [10, -10, 10.1, -10.1, 1j,
                       [10], ['ten'], [u'ten'], {'ten': 10},(10,), None]
     if not py3compat.PY3:
         _bad_values.extend([long(10), long(-10)])
 
 
 class ObjectNameTrait(HasTraits):
     value = ObjectName("abc")
 
 class TestObjectName(TraitTestBase):
     obj = ObjectNameTrait()
 
     _default_value = "abc"
     _good_values = ["a", "gh", "g9", "g_", "_G", u"a345_"]
     _bad_values = [1, "", u"€", "9g", "!", "#abc", "aj@", "a.b", "a()", "a[0]",
                                                         None, object(), object]
     if sys.version_info[0] < 3:
         _bad_values.append(u"þ")
     else:
         _good_values.append(u"þ")  # þ=1 is valid in Python 3 (PEP 3131).
 
 
 class DottedObjectNameTrait(HasTraits):
     value = DottedObjectName("a.b")
 
 class TestDottedObjectName(TraitTestBase):
     obj = DottedObjectNameTrait()
 
     _default_value = "a.b"
     _good_values = ["A", "y.t", "y765.__repr__", "os.path.join", u"os.path.join"]
     _bad_values = [1, u"abc.€", "_.@", ".", ".abc", "abc.", ".abc.", None]
     if sys.version_info[0] < 3:
         _bad_values.append(u"t.þ")
     else:
         _good_values.append(u"t.þ")
 
 
 class TCPAddressTrait(HasTraits):
 
     value = TCPAddress()
 
 class TestTCPAddress(TraitTestBase):
 
     obj = TCPAddressTrait()
 
     _default_value = ('127.0.0.1',0)
     _good_values = [('localhost',0),('192.168.0.1',1000),('www.google.com',80)]
     _bad_values = [(0,0),('localhost',10.0),('localhost',-1), None]
 
 class ListTrait(HasTraits):
 
     value = List(Int)
 
 class TestList(TraitTestBase):
 
     obj = ListTrait()
 
     _default_value = []
     _good_values = [[], [1], list(range(10)), (1,2)]
     _bad_values = [10, [1,'a'], 'a']
     
     def coerce(self, value):
         if value is not None:
             value = list(value)
         return value
 
 class Foo(object):
     pass
 
 class NoneInstanceListTrait(HasTraits):
     
     value = List(Instance(Foo, allow_none=False))
 
 class TestNoneInstanceList(TraitTestBase):
 
     obj = NoneInstanceListTrait()
 
     _default_value = []
     _good_values = [[Foo(), Foo()], []]
     _bad_values = [[None], [Foo(), None]]
 
 
 class InstanceListTrait(HasTraits):
 
     value = List(Instance(__name__+'.Foo'))
 
 class TestInstanceList(TraitTestBase):
 
     obj = InstanceListTrait()
 
     def test_klass(self):
         """Test that the instance klass is properly assigned."""
         self.assertIs(self.obj.traits()['value']._trait.klass, Foo)
 
     _default_value = []
-    _good_values = [[Foo(), Foo(), None], None]
-    _bad_values = [['1', 2,], '1', [Foo]]
+    _good_values = [[Foo(), Foo(), None], []]
+    _bad_values = [['1', 2,], '1', [Foo], None]
 
 class LenListTrait(HasTraits):
 
     value = List(Int, [0], minlen=1, maxlen=2)
 
 class TestLenList(TraitTestBase):
 
     obj = LenListTrait()
 
     _default_value = [0]
     _good_values = [[1], [1,2], (1,2)]
     _bad_values = [10, [1,'a'], 'a', [], list(range(3))]
 
     def coerce(self, value):
         if value is not None:
             value = list(value)
         return value
 
 class TupleTrait(HasTraits):
 
     value = Tuple(Int(allow_none=True))
 
 class TestTupleTrait(TraitTestBase):
 
     obj = TupleTrait()
 
     _default_value = None
     _good_values = [(1,), None, (0,), [1], (None,)]
     _bad_values = [10, (1,2), ('a'), ()]
 
     def coerce(self, value):
         if value is not None:
             value = tuple(value)
         return value
 
     def test_invalid_args(self):
         self.assertRaises(TypeError, Tuple, 5)
         self.assertRaises(TypeError, Tuple, default_value='hello')
         t = Tuple(Int, CBytes, default_value=(1,5))
 
 class LooseTupleTrait(HasTraits):
 
     value = Tuple((1,2,3))
 
 class TestLooseTupleTrait(TraitTestBase):
 
     obj = LooseTupleTrait()
 
     _default_value = (1,2,3)
     _good_values = [(1,), None, [1], (0,), tuple(range(5)), tuple('hello'), ('a',5), ()]
     _bad_values = [10, 'hello', {}]
 
     def coerce(self, value):
         if value is not None:
             value = tuple(value)
         return value
 
     def test_invalid_args(self):
         self.assertRaises(TypeError, Tuple, 5)
         self.assertRaises(TypeError, Tuple, default_value='hello')
         t = Tuple(Int, CBytes, default_value=(1,5))
 
 
 class MultiTupleTrait(HasTraits):
 
     value = Tuple(Int, Bytes, default_value=[99,b'bottles'])
 
 class TestMultiTuple(TraitTestBase):
 
     obj = MultiTupleTrait()
 
     _default_value = (99,b'bottles')
     _good_values = [(1,b'a'), (2,b'b')]
     _bad_values = ((),10, b'a', (1,b'a',3), (b'a',1), (1, u'a'))
 
 class CRegExpTrait(HasTraits):
 
     value = CRegExp(r'')
 
 class TestCRegExp(TraitTestBase):
 
     def coerce(self, value):
         return re.compile(value)
 
     obj = CRegExpTrait()
 
     _default_value = re.compile(r'')
     _good_values = [r'\d+', re.compile(r'\d+')]
     _bad_values = ['(', None, ()]
 
 class DictTrait(HasTraits):
     value = Dict()
 
 def test_dict_assignment():
     d = dict()
     c = DictTrait()
     c.value = d
     d['a'] = 5
     nt.assert_equal(d, c.value)
     nt.assert_true(c.value is d)
 
 def test_dict_default_value():
     """Check that the `{}` default value of the Dict traitlet constructor is
     actually copied."""
 
     d1, d2 = Dict(), Dict()
     nt.assert_false(d1.get_default_value() is d2.get_default_value())
 
 
 class TestValidationHook(TestCase):
 
     def test_parity_trait(self):
         """Verify that the early validation hook is effective"""
 
         class Parity(HasTraits):
 
             value = Int(0)
             parity = Enum(['odd', 'even'], default_value='even', allow_none=False)
 
             def _value_validate(self, value, trait):
                 if self.parity == 'even' and value % 2:
                     raise TraitError('Expected an even number')
                 if self.parity == 'odd' and (value % 2 == 0):
                     raise TraitError('Expected an odd number')
                 return value
         
         u = Parity()
         u.parity = 'odd'
         u.value = 1  # OK
         with self.assertRaises(TraitError):
             u.value = 2  # Trait Error
 
         u.parity = 'even'
         u.value = 2  # OK
 
 
 class TestLink(TestCase):
 
     def test_connect_same(self):
         """Verify two traitlets of the same type can be linked together using link."""
 
         # Create two simple classes with Int traitlets.
         class A(HasTraits):
             value = Int()
         a = A(value=9)
         b = A(value=8)
 
         # Conenct the two classes.
         c = link((a, 'value'), (b, 'value'))
 
         # Make sure the values are the same at the point of linking.
         self.assertEqual(a.value, b.value)
 
         # Change one of the values to make sure they stay in sync.
         a.value = 5
         self.assertEqual(a.value, b.value)
         b.value = 6
         self.assertEqual(a.value, b.value)
 
     def test_link_different(self):
         """Verify two traitlets of different types can be linked together using link."""
 
         # Create two simple classes with Int traitlets.
         class A(HasTraits):
             value = Int()
         class B(HasTraits):
             count = Int()
         a = A(value=9)
         b = B(count=8)
 
         # Conenct the two classes.
         c = link((a, 'value'), (b, 'count'))
 
         # Make sure the values are the same at the point of linking.
         self.assertEqual(a.value, b.count)
 
         # Change one of the values to make sure they stay in sync.
         a.value = 5
         self.assertEqual(a.value, b.count)
         b.count = 4
         self.assertEqual(a.value, b.count)
 
     def test_unlink(self):
         """Verify two linked traitlets can be unlinked."""
 
         # Create two simple classes with Int traitlets.
         class A(HasTraits):
             value = Int()
         a = A(value=9)
         b = A(value=8)
 
         # Connect the two classes.
         c = link((a, 'value'), (b, 'value'))
         a.value = 4
         c.unlink()
 
         # Change one of the values to make sure they don't stay in sync.
         a.value = 5
         self.assertNotEqual(a.value, b.value)
 
     def test_callbacks(self):
         """Verify two linked traitlets have their callbacks called once."""
 
         # Create two simple classes with Int traitlets.
         class A(HasTraits):
             value = Int()
         class B(HasTraits):
             count = Int()
         a = A(value=9)
         b = B(count=8)
         
         # Register callbacks that count.
         callback_count = []
         def a_callback(name, old, new):
             callback_count.append('a')
         a.on_trait_change(a_callback, 'value')
         def b_callback(name, old, new):
             callback_count.append('b')
         b.on_trait_change(b_callback, 'count')
 
         # Connect the two classes.
         c = link((a, 'value'), (b, 'count'))
 
         # Make sure b's count was set to a's value once.
         self.assertEqual(''.join(callback_count), 'b')
         del callback_count[:]
 
         # Make sure a's value was set to b's count once.
         b.count = 5
         self.assertEqual(''.join(callback_count), 'ba')
         del callback_count[:]
 
         # Make sure b's count was set to a's value once.
         a.value = 4
         self.assertEqual(''.join(callback_count), 'ab')
         del callback_count[:]
 
 class TestDirectionalLink(TestCase):
     def test_connect_same(self):
         """Verify two traitlets of the same type can be linked together using directional_link."""
 
         # Create two simple classes with Int traitlets.
         class A(HasTraits):
             value = Int()
         a = A(value=9)
         b = A(value=8)
 
         # Conenct the two classes.
         c = directional_link((a, 'value'), (b, 'value'))
 
         # Make sure the values are the same at the point of linking.
         self.assertEqual(a.value, b.value)
 
         # Change one the value of the source and check that it synchronizes the target.
         a.value = 5
         self.assertEqual(b.value, 5)
         # Change one the value of the target and check that it has no impact on the source
         b.value = 6
         self.assertEqual(a.value, 5)
 
     def test_link_different(self):
         """Verify two traitlets of different types can be linked together using link."""
 
         # Create two simple classes with Int traitlets.
         class A(HasTraits):
             value = Int()
         class B(HasTraits):
             count = Int()
         a = A(value=9)
         b = B(count=8)
 
         # Conenct the two classes.
         c = directional_link((a, 'value'), (b, 'count'))
 
         # Make sure the values are the same at the point of linking.
         self.assertEqual(a.value, b.count)
 
         # Change one the value of the source and check that it synchronizes the target.
         a.value = 5
         self.assertEqual(b.count, 5)
         # Change one the value of the target and check that it has no impact on the source
         b.value = 6
         self.assertEqual(a.value, 5)
 
     def test_unlink(self):
         """Verify two linked traitlets can be unlinked."""
 
         # Create two simple classes with Int traitlets.
         class A(HasTraits):
             value = Int()
         a = A(value=9)
         b = A(value=8)
 
         # Connect the two classes.
         c = directional_link((a, 'value'), (b, 'value'))
         a.value = 4
         c.unlink()
 
         # Change one of the values to make sure they don't stay in sync.
         a.value = 5
         self.assertNotEqual(a.value, b.value)
 
 class Pickleable(HasTraits):
     i = Int()
     j = Int()
     
     def _i_default(self):
         return 1
     
     def _i_changed(self, name, old, new):
         self.j = new
 
 def test_pickle_hastraits():
     c = Pickleable()
     for protocol in range(pickle.HIGHEST_PROTOCOL + 1):
         p = pickle.dumps(c, protocol)
         c2 = pickle.loads(p)
         nt.assert_equal(c2.i, c.i)
         nt.assert_equal(c2.j, c.j)
 
     c.i = 5
     for protocol in range(pickle.HIGHEST_PROTOCOL + 1):
         p = pickle.dumps(c, protocol)
         c2 = pickle.loads(p)
         nt.assert_equal(c2.i, c.i)
         nt.assert_equal(c2.j, c.j)
 
 class TestEventful(TestCase):
 
     def test_list(self):
         """Does the EventfulList work?"""
         event_cache = []
 
         class A(HasTraits):
             x = EventfulList([c for c in 'abc'])
         a = A()
         a.x.on_events(lambda i, x: event_cache.append('insert'), \
             lambda i, x: event_cache.append('set'), \
             lambda i: event_cache.append('del'), \
             lambda: event_cache.append('reverse'), \
             lambda *p, **k: event_cache.append('sort'))
 
         a.x.remove('c')
         # ab
         a.x.insert(0, 'z')
         # zab
         del a.x[1]
         # zb
         a.x.reverse()
         # bz 
         a.x[1] = 'o'
         # bo
         a.x.append('a')
         # boa
         a.x.sort()
         # abo
 
         # Were the correct events captured?
         self.assertEqual(event_cache, ['del', 'insert', 'del', 'reverse', 'set', 'set', 'sort'])
 
         # Is the output correct?
         self.assertEqual(a.x, [c for c in 'abo'])
 
     def test_dict(self):
         """Does the EventfulDict work?"""
         event_cache = []
 
         class A(HasTraits):
             x = EventfulDict({c: c for c in 'abc'})
         a = A()
         a.x.on_events(lambda k, v: event_cache.append('add'), \
             lambda k, v: event_cache.append('set'), \
             lambda k: event_cache.append('del'))
 
         del a.x['c']
         # ab
         a.x['z'] = 1
         # abz
         a.x['z'] = 'z'
         # abz
         a.x.pop('a')
         # bz 
 
         # Were the correct events captured?
         self.assertEqual(event_cache, ['del', 'add', 'set', 'del'])
 
         # Is the output correct?
         self.assertEqual(a.x, {c: c for c in 'bz'})
 
 ###
 # Traits for Forward Declaration Tests
 ###
 class ForwardDeclaredInstanceTrait(HasTraits):
 
     value = ForwardDeclaredInstance('ForwardDeclaredBar')
 
 class ForwardDeclaredTypeTrait(HasTraits):
 
     value = ForwardDeclaredType('ForwardDeclaredBar')
 
 class ForwardDeclaredInstanceListTrait(HasTraits):
 
     value = List(ForwardDeclaredInstance('ForwardDeclaredBar'))
 
 class ForwardDeclaredTypeListTrait(HasTraits):
 
     value = List(ForwardDeclaredType('ForwardDeclaredBar'))
 ###
 # End Traits for Forward Declaration Tests
 ###
 
 ###
 # Classes for Forward Declaration Tests
 ###
 class ForwardDeclaredBar(object):
     pass
 
 class ForwardDeclaredBarSub(ForwardDeclaredBar):
     pass
 ###
 # End Classes for Forward Declaration Tests
 ###
 
 ###
 # Forward Declaration Tests
 ###
 class TestForwardDeclaredInstanceTrait(TraitTestBase):
 
     obj = ForwardDeclaredInstanceTrait()
     _default_value = None
     _good_values = [None, ForwardDeclaredBar(), ForwardDeclaredBarSub()]
     _bad_values = ['foo', 3, ForwardDeclaredBar, ForwardDeclaredBarSub]
 
 class TestForwardDeclaredTypeTrait(TraitTestBase):
 
     obj = ForwardDeclaredTypeTrait()
     _default_value = None
     _good_values = [None, ForwardDeclaredBar, ForwardDeclaredBarSub]
     _bad_values = ['foo', 3, ForwardDeclaredBar(), ForwardDeclaredBarSub()]
 
 class TestForwardDeclaredInstanceList(TraitTestBase):
 
     obj = ForwardDeclaredInstanceListTrait()
 
     def test_klass(self):
         """Test that the instance klass is properly assigned."""
         self.assertIs(self.obj.traits()['value']._trait.klass, ForwardDeclaredBar)
 
     _default_value = []
     _good_values = [
         [ForwardDeclaredBar(), ForwardDeclaredBarSub(), None],
         [None],
         [],
-        None,
     ]
     _bad_values = [
         ForwardDeclaredBar(),
         [ForwardDeclaredBar(), 3],
         '1',
         # Note that this is the type, not an instance.
-        [ForwardDeclaredBar]
+        [ForwardDeclaredBar],
+        None,
     ]
 
 class TestForwardDeclaredTypeList(TraitTestBase):
 
     obj = ForwardDeclaredTypeListTrait()
 
     def test_klass(self):
         """Test that the instance klass is properly assigned."""
         self.assertIs(self.obj.traits()['value']._trait.klass, ForwardDeclaredBar)
 
     _default_value = []
     _good_values = [
         [ForwardDeclaredBar, ForwardDeclaredBarSub, None],
         [],
         [None],
-        None,
     ]
     _bad_values = [
         ForwardDeclaredBar,
         [ForwardDeclaredBar, 3],
         '1',
         # Note that this is an instance, not the type.
-        [ForwardDeclaredBar()]
+        [ForwardDeclaredBar()],
+        None,
     ]
 ###
 # End Forward Declaration Tests
 ###

IPython/utils/traitlets.py

@@ -1,1734 +1,1732 b''
 # encoding: utf-8
 """
 A lightweight Traits like module.
 
 This is designed to provide a lightweight, simple, pure Python version of
 many of the capabilities of enthought.traits.  This includes:
 
 * Validation
 * Type specification with defaults
 * Static and dynamic notification
 * Basic predefined types
 * An API that is similar to enthought.traits
 
 We don't support:
 
 * Delegation
 * Automatic GUI generation
 * A full set of trait types.  Most importantly, we don't provide container
   traits (list, dict, tuple) that can trigger notifications if their
   contents change.
 * API compatibility with enthought.traits
 
 There are also some important difference in our design:
 
 * enthought.traits does not validate default values.  We do.
 
 We choose to create this module because we need these capabilities, but
 we need them to be pure Python so they work in all Python implementations,
 including Jython and IronPython.
 
 Inheritance diagram:
 
 .. inheritance-diagram:: IPython.utils.traitlets
    :parts: 3
 """
 
 # Copyright (c) IPython Development Team.
 # Distributed under the terms of the Modified BSD License.
 #
 # Adapted from enthought.traits, Copyright (c) Enthought, Inc.,
 # also under the terms of the Modified BSD License.
 
 import contextlib
 import inspect
 import re
 import sys
 import types
 from types import FunctionType
 try:
     from types import ClassType, InstanceType
     ClassTypes = (ClassType, type)
 except:
     ClassTypes = (type,)
 
 from .importstring import import_item
 from IPython.utils import py3compat
 from IPython.utils import eventful
 from IPython.utils.py3compat import iteritems, string_types
 from IPython.testing.skipdoctest import skip_doctest
 
 SequenceTypes = (list, tuple, set, frozenset)
 
 #-----------------------------------------------------------------------------
 # Basic classes
 #-----------------------------------------------------------------------------
 
 
 class NoDefaultSpecified ( object ): pass
 NoDefaultSpecified = NoDefaultSpecified()
 
 
 class Undefined ( object ): pass
 Undefined = Undefined()
 
 class TraitError(Exception):
     pass
 
 #-----------------------------------------------------------------------------
 # Utilities
 #-----------------------------------------------------------------------------
 
 
 def class_of ( object ):
     """ Returns a string containing the class name of an object with the
     correct indefinite article ('a' or 'an') preceding it (e.g., 'an Image',
     'a PlotValue').
     """
     if isinstance( object, py3compat.string_types ):
         return add_article( object )
 
     return add_article( object.__class__.__name__ )
 
 
 def add_article ( name ):
     """ Returns a string containing the correct indefinite article ('a' or 'an')
     prefixed to the specified string.
     """
     if name[:1].lower() in 'aeiou':
        return 'an ' + name
 
     return 'a ' + name
 
 
 def repr_type(obj):
     """ Return a string representation of a value and its type for readable
     error messages.
     """
     the_type = type(obj)
     if (not py3compat.PY3) and the_type is InstanceType:
         # Old-style class.
         the_type = obj.__class__
     msg = '%r %r' % (obj, the_type)
     return msg
 
 
 def is_trait(t):
     """ Returns whether the given value is an instance or subclass of TraitType.
     """
     return (isinstance(t, TraitType) or
             (isinstance(t, type) and issubclass(t, TraitType)))
 
 
 def parse_notifier_name(name):
     """Convert the name argument to a list of names.
 
     Examples
     --------
 
     >>> parse_notifier_name('a')
     ['a']
     >>> parse_notifier_name(['a','b'])
     ['a', 'b']
     >>> parse_notifier_name(None)
     ['anytrait']
     """
     if isinstance(name, string_types):
         return [name]
     elif name is None:
         return ['anytrait']
     elif isinstance(name, (list, tuple)):
         for n in name:
             assert isinstance(n, string_types), "names must be strings"
         return name
 
 
 class _SimpleTest:
     def __init__ ( self, value ): self.value = value
     def __call__ ( self, test  ):
         return test == self.value
     def __repr__(self):
         return "<SimpleTest(%r)" % self.value
     def __str__(self):
         return self.__repr__()
 
 
 def getmembers(object, predicate=None):
     """A safe version of inspect.getmembers that handles missing attributes.
 
     This is useful when there are descriptor based attributes that for
     some reason raise AttributeError even though they exist.  This happens
     in zope.inteface with the __provides__ attribute.
     """
     results = []
     for key in dir(object):
         try:
             value = getattr(object, key)
         except AttributeError:
             pass
         else:
             if not predicate or predicate(value):
                 results.append((key, value))
     results.sort()
     return results
 
 def _validate_link(*tuples):
     """Validate arguments for traitlet link functions"""
     for t in tuples:
         if not len(t) == 2:
             raise TypeError("Each linked traitlet must be specified as (HasTraits, 'trait_name'), not %r" % t)
         obj, trait_name = t
         if not isinstance(obj, HasTraits):
             raise TypeError("Each object must be HasTraits, not %r" % type(obj))
         if not trait_name in obj.traits():
             raise TypeError("%r has no trait %r" % (obj, trait_name))
 
 @skip_doctest
 class link(object):
     """Link traits from different objects together so they remain in sync.
 
     Parameters
     ----------
     *args : pairs of objects/attributes
 
     Examples
     --------
 
     >>> c = link((obj1, 'value'), (obj2, 'value'), (obj3, 'value'))
     >>> obj1.value = 5 # updates other objects as well
     """
     updating = False
     def __init__(self, *args):
         if len(args) < 2:
             raise TypeError('At least two traitlets must be provided.')
         _validate_link(*args)
 
         self.objects = {}
 
         initial = getattr(args[0][0], args[0][1])
         for obj, attr in args:
             setattr(obj, attr, initial)
 
             callback = self._make_closure(obj, attr)
             obj.on_trait_change(callback, attr)
             self.objects[(obj, attr)] = callback
 
     @contextlib.contextmanager
     def _busy_updating(self):
         self.updating = True
         try:
             yield
         finally:
             self.updating = False
 
     def _make_closure(self, sending_obj, sending_attr):
         def update(name, old, new):
             self._update(sending_obj, sending_attr, new)
         return update
 
     def _update(self, sending_obj, sending_attr, new):
         if self.updating:
             return
         with self._busy_updating():
             for obj, attr in self.objects.keys():
                 setattr(obj, attr, new)
 
     def unlink(self):
         for key, callback in self.objects.items():
             (obj, attr) = key
             obj.on_trait_change(callback, attr, remove=True)
 
 @skip_doctest
 class directional_link(object):
     """Link the trait of a source object with traits of target objects.
 
     Parameters
     ----------
     source : pair of object, name
     targets : pairs of objects/attributes
 
     Examples
     --------
 
     >>> c = directional_link((src, 'value'), (tgt1, 'value'), (tgt2, 'value'))
     >>> src.value = 5  # updates target objects
     >>> tgt1.value = 6 # does not update other objects
     """
     updating = False
 
     def __init__(self, source, *targets):
         if len(targets) < 1:
             raise TypeError('At least two traitlets must be provided.')
         _validate_link(source, *targets)
         self.source = source
         self.targets = targets
 
         # Update current value
         src_attr_value = getattr(source[0], source[1])
         for obj, attr in targets:
             setattr(obj, attr, src_attr_value)
 
         # Wire
         self.source[0].on_trait_change(self._update, self.source[1])
 
     @contextlib.contextmanager
     def _busy_updating(self):
         self.updating = True
         try:
             yield
         finally:
             self.updating = False
 
     def _update(self, name, old, new):
         if self.updating:
             return
         with self._busy_updating():
             for obj, attr in self.targets:
                 setattr(obj, attr, new)
 
     def unlink(self):
         self.source[0].on_trait_change(self._update, self.source[1], remove=True)
         self.source = None
         self.targets = []
 
 dlink = directional_link
 
 #-----------------------------------------------------------------------------
 # Base TraitType for all traits
 #-----------------------------------------------------------------------------
 
 
 class TraitType(object):
     """A base class for all trait descriptors.
 
     Notes
     -----
     Our implementation of traits is based on Python's descriptor
     prototol.  This class is the base class for all such descriptors.  The
     only magic we use is a custom metaclass for the main :class:`HasTraits`
     class that does the following:
 
     1. Sets the :attr:`name` attribute of every :class:`TraitType`
        instance in the class dict to the name of the attribute.
     2. Sets the :attr:`this_class` attribute of every :class:`TraitType`
        instance in the class dict to the *class* that declared the trait.
        This is used by the :class:`This` trait to allow subclasses to
        accept superclasses for :class:`This` values.
     """
 
 
     metadata = {}
     default_value = Undefined
     allow_none = False
     info_text = 'any value'
 
     def __init__(self, default_value=NoDefaultSpecified, allow_none=None, **metadata):
         """Create a TraitType.
         """
         if default_value is not NoDefaultSpecified:
             self.default_value = default_value
         if allow_none is not None:
             self.allow_none = allow_none
 
         if len(metadata) > 0:
             if len(self.metadata) > 0:
                 self._metadata = self.metadata.copy()
                 self._metadata.update(metadata)
             else:
                 self._metadata = metadata
         else:
             self._metadata = self.metadata
 
         self.init()
 
     def init(self):
         pass
 
     def get_default_value(self):
         """Create a new instance of the default value."""
         return self.default_value
 
     def instance_init(self, obj):
         """This is called by :meth:`HasTraits.__new__` to finish init'ing.
 
         Some stages of initialization must be delayed until the parent
         :class:`HasTraits` instance has been created.  This method is
         called in :meth:`HasTraits.__new__` after the instance has been
         created.
 
         This method trigger the creation and validation of default values
         and also things like the resolution of str given class names in
         :class:`Type` and :class`Instance`.
 
         Parameters
         ----------
         obj : :class:`HasTraits` instance
             The parent :class:`HasTraits` instance that has just been
             created.
         """
         self.set_default_value(obj)
 
     def set_default_value(self, obj):
         """Set the default value on a per instance basis.
 
         This method is called by :meth:`instance_init` to create and
         validate the default value.  The creation and validation of
         default values must be delayed until the parent :class:`HasTraits`
         class has been instantiated.
         """
         # Check for a deferred initializer defined in the same class as the
         # trait declaration or above.
         mro = type(obj).mro()
         meth_name = '_%s_default' % self.name
         for cls in mro[:mro.index(self.this_class)+1]:
             if meth_name in cls.__dict__:
                 break
         else:
             # We didn't find one. Do static initialization.
             dv = self.get_default_value()
             newdv = self._validate(obj, dv)
             obj._trait_values[self.name] = newdv
             return
         # Complete the dynamic initialization.
         obj._trait_dyn_inits[self.name] = meth_name
     
     def __get__(self, obj, cls=None):
         """Get the value of the trait by self.name for the instance.
 
         Default values are instantiated when :meth:`HasTraits.__new__`
         is called.  Thus by the time this method gets called either the
         default value or a user defined value (they called :meth:`__set__`)
         is in the :class:`HasTraits` instance.
         """
         if obj is None:
             return self
         else:
             try:
                 value = obj._trait_values[self.name]
             except KeyError:
                 # Check for a dynamic initializer.
                 if self.name in obj._trait_dyn_inits:
                     method = getattr(obj, obj._trait_dyn_inits[self.name])
                     value = method()
                     # FIXME: Do we really validate here?
                     value = self._validate(obj, value)
                     obj._trait_values[self.name] = value
                     return value
                 else:
                     raise TraitError('Unexpected error in TraitType: '
                         'both default value and dynamic initializer are '
                         'absent.')
             except Exception:
                 # HasTraits should call set_default_value to populate
                 # this.  So this should never be reached.
                 raise TraitError('Unexpected error in TraitType: '
                                     'default value not set properly')
             else:
                 return value
 
     def __set__(self, obj, value):
         new_value = self._validate(obj, value)
         try:
             old_value = obj._trait_values[self.name]
         except KeyError:
             old_value = None
 
         obj._trait_values[self.name] = new_value
         try:
             silent = bool(old_value == new_value)
         except:
             # if there is an error in comparing, default to notify
             silent = False
         if silent is not True:
             # we explicitly compare silent to True just in case the equality
             # comparison above returns something other than True/False
             obj._notify_trait(self.name, old_value, new_value)
 
     def _validate(self, obj, value):
         if value is None and self.allow_none:
             return value
         if hasattr(self, 'validate'):
             value = self.validate(obj, value)
         if hasattr(obj, '_%s_validate' % self.name):
             value = getattr(obj, '_%s_validate' % self.name)(value, self)
         return value
 
     def __or__(self, other):
         if isinstance(other, Union):
             return Union([self] + other.trait_types)
         else:
             return Union([self, other])
 
     def info(self):
         return self.info_text
 
     def error(self, obj, value):
         if obj is not None:
             e = "The '%s' trait of %s instance must be %s, but a value of %s was specified." \
                 % (self.name, class_of(obj),
                    self.info(), repr_type(value))
         else:
             e = "The '%s' trait must be %s, but a value of %r was specified." \
                 % (self.name, self.info(), repr_type(value))
         raise TraitError(e)
 
     def get_metadata(self, key, default=None):
         return getattr(self, '_metadata', {}).get(key, default)
 
     def set_metadata(self, key, value):
         getattr(self, '_metadata', {})[key] = value
 
 
 #-----------------------------------------------------------------------------
 # The HasTraits implementation
 #-----------------------------------------------------------------------------
 
 
 class MetaHasTraits(type):
     """A metaclass for HasTraits.
 
     This metaclass makes sure that any TraitType class attributes are
     instantiated and sets their name attribute.
     """
 
     def __new__(mcls, name, bases, classdict):
         """Create the HasTraits class.
 
         This instantiates all TraitTypes in the class dict and sets their
         :attr:`name` attribute.
         """
         # print "MetaHasTraitlets (mcls, name): ", mcls, name
         # print "MetaHasTraitlets (bases): ", bases
         # print "MetaHasTraitlets (classdict): ", classdict
         for k,v in iteritems(classdict):
             if isinstance(v, TraitType):
                 v.name = k
             elif inspect.isclass(v):
                 if issubclass(v, TraitType):
                     vinst = v()
                     vinst.name = k
                     classdict[k] = vinst
         return super(MetaHasTraits, mcls).__new__(mcls, name, bases, classdict)
 
     def __init__(cls, name, bases, classdict):
         """Finish initializing the HasTraits class.
 
         This sets the :attr:`this_class` attribute of each TraitType in the
         class dict to the newly created class ``cls``.
         """
         for k, v in iteritems(classdict):
             if isinstance(v, TraitType):
                 v.this_class = cls
         super(MetaHasTraits, cls).__init__(name, bases, classdict)
 
 class HasTraits(py3compat.with_metaclass(MetaHasTraits, object)):
 
     def __new__(cls, *args, **kw):
         # This is needed because object.__new__ only accepts
         # the cls argument.
         new_meth = super(HasTraits, cls).__new__
         if new_meth is object.__new__:
             inst = new_meth(cls)
         else:
             inst = new_meth(cls, **kw)
         inst._trait_values = {}
         inst._trait_notifiers = {}
         inst._trait_dyn_inits = {}
         # Here we tell all the TraitType instances to set their default
         # values on the instance.
         for key in dir(cls):
             # Some descriptors raise AttributeError like zope.interface's
             # __provides__ attributes even though they exist.  This causes
             # AttributeErrors even though they are listed in dir(cls).
             try:
                 value = getattr(cls, key)
             except AttributeError:
                 pass
             else:
                 if isinstance(value, TraitType):
                     value.instance_init(inst)
 
         return inst
 
     def __init__(self, *args, **kw):
         # Allow trait values to be set using keyword arguments.
         # We need to use setattr for this to trigger validation and
         # notifications.
         for key, value in iteritems(kw):
             setattr(self, key, value)
 
     def _notify_trait(self, name, old_value, new_value):
 
         # First dynamic ones
         callables = []
         callables.extend(self._trait_notifiers.get(name,[]))
         callables.extend(self._trait_notifiers.get('anytrait',[]))
 
         # Now static ones
         try:
             cb = getattr(self, '_%s_changed' % name)
         except:
             pass
         else:
             callables.append(cb)
 
         # Call them all now
         for c in callables:
             # Traits catches and logs errors here.  I allow them to raise
             if callable(c):
                 argspec = inspect.getargspec(c)
                 nargs = len(argspec[0])
                 # Bound methods have an additional 'self' argument
                 # I don't know how to treat unbound methods, but they
                 # can't really be used for callbacks.
                 if isinstance(c, types.MethodType):
                     offset = -1
                 else:
                     offset = 0
                 if nargs + offset == 0:
                     c()
                 elif nargs + offset == 1:
                     c(name)
                 elif nargs + offset == 2:
                     c(name, new_value)
                 elif nargs + offset == 3:
                     c(name, old_value, new_value)
                 else:
                     raise TraitError('a trait changed callback '
                                         'must have 0-3 arguments.')
             else:
                 raise TraitError('a trait changed callback '
                                     'must be callable.')
 
 
     def _add_notifiers(self, handler, name):
         if name not in self._trait_notifiers:
             nlist = []
             self._trait_notifiers[name] = nlist
         else:
             nlist = self._trait_notifiers[name]
         if handler not in nlist:
             nlist.append(handler)
 
     def _remove_notifiers(self, handler, name):
         if name in self._trait_notifiers:
             nlist = self._trait_notifiers[name]
             try:
                 index = nlist.index(handler)
             except ValueError:
                 pass
             else:
                 del nlist[index]
 
     def on_trait_change(self, handler, name=None, remove=False):
         """Setup a handler to be called when a trait changes.
 
         This is used to setup dynamic notifications of trait changes.
 
         Static handlers can be created by creating methods on a HasTraits
         subclass with the naming convention '_[traitname]_changed'.  Thus,
         to create static handler for the trait 'a', create the method
         _a_changed(self, name, old, new) (fewer arguments can be used, see
         below).
 
         Parameters
         ----------
         handler : callable
             A callable that is called when a trait changes.  Its
             signature can be handler(), handler(name), handler(name, new)
             or handler(name, old, new).
         name : list, str, None
             If None, the handler will apply to all traits.  If a list
             of str, handler will apply to all names in the list.  If a
             str, the handler will apply just to that name.
         remove : bool
             If False (the default), then install the handler.  If True
             then unintall it.
         """
         if remove:
             names = parse_notifier_name(name)
             for n in names:
                 self._remove_notifiers(handler, n)
         else:
             names = parse_notifier_name(name)
             for n in names:
                 self._add_notifiers(handler, n)
 
     @classmethod
     def class_trait_names(cls, **metadata):
         """Get a list of all the names of this class' traits.
 
         This method is just like the :meth:`trait_names` method,
         but is unbound.
         """
         return cls.class_traits(**metadata).keys()
 
     @classmethod
     def class_traits(cls, **metadata):
         """Get a `dict` of all the traits of this class.  The dictionary
         is keyed on the name and the values are the TraitType objects.
 
         This method is just like the :meth:`traits` method, but is unbound.
 
         The TraitTypes returned don't know anything about the values
         that the various HasTrait's instances are holding.
 
         The metadata kwargs allow functions to be passed in which
         filter traits based on metadata values.  The functions should
         take a single value as an argument and return a boolean.  If
         any function returns False, then the trait is not included in
         the output.  This does not allow for any simple way of
         testing that a metadata name exists and has any
         value because get_metadata returns None if a metadata key
         doesn't exist.
         """
         traits = dict([memb for memb in getmembers(cls) if
                      isinstance(memb[1], TraitType)])
 
         if len(metadata) == 0:
             return traits
 
         for meta_name, meta_eval in metadata.items():
             if type(meta_eval) is not FunctionType:
                 metadata[meta_name] = _SimpleTest(meta_eval)
 
         result = {}
         for name, trait in traits.items():
             for meta_name, meta_eval in metadata.items():
                 if not meta_eval(trait.get_metadata(meta_name)):
                     break
             else:
                 result[name] = trait
 
         return result
 
     def trait_names(self, **metadata):
         """Get a list of all the names of this class' traits."""
         return self.traits(**metadata).keys()
 
     def traits(self, **metadata):
         """Get a `dict` of all the traits of this class.  The dictionary
         is keyed on the name and the values are the TraitType objects.
 
         The TraitTypes returned don't know anything about the values
         that the various HasTrait's instances are holding.
 
         The metadata kwargs allow functions to be passed in which
         filter traits based on metadata values.  The functions should
         take a single value as an argument and return a boolean.  If
         any function returns False, then the trait is not included in
         the output.  This does not allow for any simple way of
         testing that a metadata name exists and has any
         value because get_metadata returns None if a metadata key
         doesn't exist.
         """
         traits = dict([memb for memb in getmembers(self.__class__) if
                      isinstance(memb[1], TraitType)])
 
         if len(metadata) == 0:
             return traits
 
         for meta_name, meta_eval in metadata.items():
             if type(meta_eval) is not FunctionType:
                 metadata[meta_name] = _SimpleTest(meta_eval)
 
         result = {}
         for name, trait in traits.items():
             for meta_name, meta_eval in metadata.items():
                 if not meta_eval(trait.get_metadata(meta_name)):
                     break
             else:
                 result[name] = trait
 
         return result
 
     def trait_metadata(self, traitname, key, default=None):
         """Get metadata values for trait by key."""
         try:
             trait = getattr(self.__class__, traitname)
         except AttributeError:
             raise TraitError("Class %s does not have a trait named %s" %
                                 (self.__class__.__name__, traitname))
         else:
             return trait.get_metadata(key, default)
 
 #-----------------------------------------------------------------------------
 # Actual TraitTypes implementations/subclasses
 #-----------------------------------------------------------------------------
 
 #-----------------------------------------------------------------------------
 # TraitTypes subclasses for handling classes and instances of classes
 #-----------------------------------------------------------------------------
 
 
 class ClassBasedTraitType(TraitType):
     """
     A trait with error reporting and string -> type resolution for Type,
     Instance and This.
     """
 
     def _resolve_string(self, string):
         """
         Resolve a string supplied for a type into an actual object.
         """
         return import_item(string)
 
     def error(self, obj, value):
         kind = type(value)
         if (not py3compat.PY3) and kind is InstanceType:
             msg = 'class %s' % value.__class__.__name__
         else:
             msg = '%s (i.e. %s)' % ( str( kind )[1:-1], repr( value ) )
 
         if obj is not None:
             e = "The '%s' trait of %s instance must be %s, but a value of %s was specified." \
                 % (self.name, class_of(obj),
                    self.info(), msg)
         else:
             e = "The '%s' trait must be %s, but a value of %r was specified." \
                 % (self.name, self.info(), msg)
 
         raise TraitError(e)
 
 
 class Type(ClassBasedTraitType):
     """A trait whose value must be a subclass of a specified class."""
 
     def __init__ (self, default_value=None, klass=None, allow_none=True, **metadata ):
         """Construct a Type trait
 
         A Type trait specifies that its values must be subclasses of
         a particular class.
 
         If only ``default_value`` is given, it is used for the ``klass`` as
         well.
 
         Parameters
         ----------
         default_value : class, str or None
             The default value must be a subclass of klass.  If an str,
             the str must be a fully specified class name, like 'foo.bar.Bah'.
             The string is resolved into real class, when the parent
             :class:`HasTraits` class is instantiated.
         klass : class, str, None
             Values of this trait must be a subclass of klass.  The klass
             may be specified in a string like: 'foo.bar.MyClass'.
             The string is resolved into real class, when the parent
             :class:`HasTraits` class is instantiated.
-        allow_none : boolean
+        allow_none : bool [ default True ]
             Indicates whether None is allowed as an assignable value. Even if
             ``False``, the default value may be ``None``.
         """
         if default_value is None:
             if klass is None:
                 klass = object
         elif klass is None:
             klass = default_value
 
         if not (inspect.isclass(klass) or isinstance(klass, py3compat.string_types)):
             raise TraitError("A Type trait must specify a class.")
 
         self.klass       = klass
 
         super(Type, self).__init__(default_value, allow_none=allow_none, **metadata)
 
     def validate(self, obj, value):
         """Validates that the value is a valid object instance."""
         if isinstance(value, py3compat.string_types):
             try:
                 value = self._resolve_string(value)
             except ImportError:
                 raise TraitError("The '%s' trait of %s instance must be a type, but "
                                 "%r could not be imported" % (self.name, obj, value))
         try:
             if issubclass(value, self.klass):
                 return value
         except:
             pass
 
         self.error(obj, value)
 
     def info(self):
         """ Returns a description of the trait."""
         if isinstance(self.klass, py3compat.string_types):
             klass = self.klass
         else:
             klass = self.klass.__name__
         result = 'a subclass of ' + klass
         if self.allow_none:
             return result + ' or None'
         return result
 
     def instance_init(self, obj):
         self._resolve_classes()
         super(Type, self).instance_init(obj)
 
     def _resolve_classes(self):
         if isinstance(self.klass, py3compat.string_types):
             self.klass = self._resolve_string(self.klass)
         if isinstance(self.default_value, py3compat.string_types):
             self.default_value = self._resolve_string(self.default_value)
 
     def get_default_value(self):
         return self.default_value
 
 
 class DefaultValueGenerator(object):
     """A class for generating new default value instances."""
 
     def __init__(self, *args, **kw):
         self.args = args
         self.kw = kw
 
     def generate(self, klass):
         return klass(*self.args, **self.kw)
 
 
 class Instance(ClassBasedTraitType):
     """A trait whose value must be an instance of a specified class.
 
     The value can also be an instance of a subclass of the specified class.
 
     Subclasses can declare default classes by overriding the klass attribute
     """
 
     klass = None
 
     def __init__(self, klass=None, args=None, kw=None,
                  allow_none=True, **metadata ):
         """Construct an Instance trait.
 
         This trait allows values that are instances of a particular
         class or its subclasses.  Our implementation is quite different
         from that of enthough.traits as we don't allow instances to be used
         for klass and we handle the ``args`` and ``kw`` arguments differently.
 
         Parameters
         ----------
         klass : class, str
             The class that forms the basis for the trait.  Class names
             can also be specified as strings, like 'foo.bar.Bar'.
         args : tuple
             Positional arguments for generating the default value.
         kw : dict
             Keyword arguments for generating the default value.
-        allow_none : bool
+        allow_none : bool [default True]
             Indicates whether None is allowed as a value.
 
         Notes
         -----
         If both ``args`` and ``kw`` are None, then the default value is None.
         If ``args`` is a tuple and ``kw`` is a dict, then the default is
         created as ``klass(*args, **kw)``.  If exactly one of ``args`` or ``kw`` is
         None, the None is replaced by ``()`` or ``{}``, respectively.
         """
         if klass is None:
             klass = self.klass
         
         if (klass is not None) and (inspect.isclass(klass) or isinstance(klass, py3compat.string_types)):
             self.klass = klass
         else:
             raise TraitError('The klass attribute must be a class'
                                 ' not: %r' % klass)
 
         # self.klass is a class, so handle default_value
         if args is None and kw is None:
             default_value = None
         else:
             if args is None:
                 # kw is not None
                 args = ()
             elif kw is None:
                 # args is not None
                 kw = {}
 
             if not isinstance(kw, dict):
                 raise TraitError("The 'kw' argument must be a dict or None.")
             if not isinstance(args, tuple):
                 raise TraitError("The 'args' argument must be a tuple or None.")
 
             default_value = DefaultValueGenerator(*args, **kw)
 
         super(Instance, self).__init__(default_value, allow_none=allow_none, **metadata)
 
     def validate(self, obj, value):
         if isinstance(value, self.klass):
             return value
         else:
             self.error(obj, value)
 
     def info(self):
         if isinstance(self.klass, py3compat.string_types):
             klass = self.klass
         else:
             klass = self.klass.__name__
         result = class_of(klass)
         if self.allow_none:
             return result + ' or None'
 
         return result
 
     def instance_init(self, obj):
         self._resolve_classes()
         super(Instance, self).instance_init(obj)
 
     def _resolve_classes(self):
         if isinstance(self.klass, py3compat.string_types):
             self.klass = self._resolve_string(self.klass)
 
     def get_default_value(self):
         """Instantiate a default value instance.
 
         This is called when the containing HasTraits classes'
         :meth:`__new__` method is called to ensure that a unique instance
         is created for each HasTraits instance.
         """
         dv  = self.default_value
         if isinstance(dv, DefaultValueGenerator):
             return dv.generate(self.klass)
         else:
             return dv
 
 
 class ForwardDeclaredMixin(object):
     """
     Mixin for forward-declared versions of Instance and Type.
     """
     def _resolve_string(self, string):
         """
         Find the specified class name by looking for it in the module in which
         our this_class attribute was defined.
         """
         modname = self.this_class.__module__
         return import_item('.'.join([modname, string]))
 
 
 class ForwardDeclaredType(ForwardDeclaredMixin, Type):
     """
     Forward-declared version of Type.
     """
     pass
 
 
 class ForwardDeclaredInstance(ForwardDeclaredMixin, Instance):
     """
     Forward-declared version of Instance.
     """
     pass
 
 
 class This(ClassBasedTraitType):
     """A trait for instances of the class containing this trait.
 
     Because how how and when class bodies are executed, the ``This``
     trait can only have a default value of None.  This, and because we
     always validate default values, ``allow_none`` is *always* true.
     """
 
     info_text = 'an instance of the same type as the receiver or None'
 
     def __init__(self, **metadata):
         super(This, self).__init__(None, **metadata)
 
     def validate(self, obj, value):
         # What if value is a superclass of obj.__class__?  This is
         # complicated if it was the superclass that defined the This
         # trait.
         if isinstance(value, self.this_class) or (value is None):
             return value
         else:
             self.error(obj, value)
 
 
 class Union(TraitType):
     """A trait type representing a Union type."""
 
     def __init__(self, trait_types, **metadata):
         """Construct a Union  trait.
 
         This trait allows values that are allowed by at least one of the
         specified trait types. A Union traitlet cannot have metadata on
         its own, besides the metadata of the listed types.
 
         Parameters
         ----------
         trait_types: sequence
             The list of trait types of length at least 1.
 
         Notes
         -----
         Union([Float(), Bool(), Int()]) attempts to validate the provided values
         with the validation function of Float, then Bool, and finally Int.
         """
         self.trait_types = trait_types
         self.info_text = " or ".join([tt.info_text for tt in self.trait_types])
         self.default_value = self.trait_types[0].get_default_value()
         super(Union, self).__init__(**metadata)
 
     def _resolve_classes(self):
         for trait_type in self.trait_types:
             trait_type.name = self.name
             trait_type.this_class = self.this_class
             if hasattr(trait_type, '_resolve_classes'):
                 trait_type._resolve_classes()
 
     def instance_init(self, obj):
         self._resolve_classes()
         super(Union, self).instance_init(obj)
 
     def validate(self, obj, value):
         for trait_type in self.trait_types:
             try:
                 v = trait_type._validate(obj, value)
                 self._metadata = trait_type._metadata
                 return v
             except TraitError:
                 continue
         self.error(obj, value)
 
     def __or__(self, other):
         if isinstance(other, Union):
             return Union(self.trait_types + other.trait_types)
         else:
             return Union(self.trait_types + [other])
 
 #-----------------------------------------------------------------------------
 # Basic TraitTypes implementations/subclasses
 #-----------------------------------------------------------------------------
 
 
 class Any(TraitType):
     default_value = None
     info_text = 'any value'
 
 
 class Int(TraitType):
     """An int trait."""
 
     default_value = 0
     info_text = 'an int'
 
     def validate(self, obj, value):
         if isinstance(value, int):
             return value
         self.error(obj, value)
 
 class CInt(Int):
     """A casting version of the int trait."""
 
     def validate(self, obj, value):
         try:
             return int(value)
         except:
             self.error(obj, value)
 
 if py3compat.PY3:
     Long, CLong = Int, CInt
     Integer = Int
 else:
     class Long(TraitType):
         """A long integer trait."""
 
         default_value = 0
         info_text = 'a long'
 
         def validate(self, obj, value):
             if isinstance(value, long):
                 return value
             if isinstance(value, int):
                 return long(value)
             self.error(obj, value)
 
 
     class CLong(Long):
         """A casting version of the long integer trait."""
 
         def validate(self, obj, value):
             try:
                 return long(value)
             except:
                 self.error(obj, value)
 
     class Integer(TraitType):
         """An integer trait.
 
         Longs that are unnecessary (<= sys.maxint) are cast to ints."""
 
         default_value = 0
         info_text = 'an integer'
 
         def validate(self, obj, value):
             if isinstance(value, int):
                 return value
             if isinstance(value, long):
                 # downcast longs that fit in int:
                 # note that int(n > sys.maxint) returns a long, so
                 # we don't need a condition on this cast
                 return int(value)
             if sys.platform == "cli":
                 from System import Int64
                 if isinstance(value, Int64):
                     return int(value)
             self.error(obj, value)
 
 
 class Float(TraitType):
     """A float trait."""
 
     default_value = 0.0
     info_text = 'a float'
 
     def validate(self, obj, value):
         if isinstance(value, float):
             return value
         if isinstance(value, int):
             return float(value)
         self.error(obj, value)
 
 
 class CFloat(Float):
     """A casting version of the float trait."""
 
     def validate(self, obj, value):
         try:
             return float(value)
         except:
             self.error(obj, value)
 
 class Complex(TraitType):
     """A trait for complex numbers."""
 
     default_value = 0.0 + 0.0j
     info_text = 'a complex number'
 
     def validate(self, obj, value):
         if isinstance(value, complex):
             return value
         if isinstance(value, (float, int)):
             return complex(value)
         self.error(obj, value)
 
 
 class CComplex(Complex):
     """A casting version of the complex number trait."""
 
     def validate (self, obj, value):
         try:
             return complex(value)
         except:
             self.error(obj, value)
 
 # We should always be explicit about whether we're using bytes or unicode, both
 # for Python 3 conversion and for reliable unicode behaviour on Python 2. So
 # we don't have a Str type.
 class Bytes(TraitType):
     """A trait for byte strings."""
 
     default_value = b''
     info_text = 'a bytes object'
 
     def validate(self, obj, value):
         if isinstance(value, bytes):
             return value
         self.error(obj, value)
 
 
 class CBytes(Bytes):
     """A casting version of the byte string trait."""
 
     def validate(self, obj, value):
         try:
             return bytes(value)
         except:
             self.error(obj, value)
 
 
 class Unicode(TraitType):
     """A trait for unicode strings."""
 
     default_value = u''
     info_text = 'a unicode string'
 
     def validate(self, obj, value):
         if isinstance(value, py3compat.unicode_type):
             return value
         if isinstance(value, bytes):
             try:
                 return value.decode('ascii', 'strict')
             except UnicodeDecodeError:
                 msg = "Could not decode {!r} for unicode trait '{}' of {} instance."
                 raise TraitError(msg.format(value, self.name, class_of(obj)))
         self.error(obj, value)
 
 
 class CUnicode(Unicode):
     """A casting version of the unicode trait."""
 
     def validate(self, obj, value):
         try:
             return py3compat.unicode_type(value)
         except:
             self.error(obj, value)
 
 
 class ObjectName(TraitType):
     """A string holding a valid object name in this version of Python.
 
     This does not check that the name exists in any scope."""
     info_text = "a valid object identifier in Python"
 
     if py3compat.PY3:
         # Python 3:
         coerce_str = staticmethod(lambda _,s: s)
 
     else:
         # Python 2:
         def coerce_str(self, obj, value):
             "In Python 2, coerce ascii-only unicode to str"
             if isinstance(value, unicode):
                 try:
                     return str(value)
                 except UnicodeEncodeError:
                     self.error(obj, value)
             return value
 
     def validate(self, obj, value):
         value = self.coerce_str(obj, value)
 
         if isinstance(value, string_types) and py3compat.isidentifier(value):
             return value
         self.error(obj, value)
 
 class DottedObjectName(ObjectName):
     """A string holding a valid dotted object name in Python, such as A.b3._c"""
     def validate(self, obj, value):
         value = self.coerce_str(obj, value)
 
         if isinstance(value, string_types) and py3compat.isidentifier(value, dotted=True):
             return value
         self.error(obj, value)
 
 
 class Bool(TraitType):
     """A boolean (True, False) trait."""
 
     default_value = False
     info_text = 'a boolean'
 
     def validate(self, obj, value):
         if isinstance(value, bool):
             return value
         self.error(obj, value)
 
 
 class CBool(Bool):
     """A casting version of the boolean trait."""
 
     def validate(self, obj, value):
         try:
             return bool(value)
         except:
             self.error(obj, value)
 
 
 class Enum(TraitType):
     """An enum that whose value must be in a given sequence."""
 
-    def __init__(self, values, default_value=None, allow_none=True, **metadata):
+    def __init__(self, values, default_value=None, **metadata):
         self.values = values
-        super(Enum, self).__init__(default_value, allow_none=allow_none, **metadata)
+        super(Enum, self).__init__(default_value, **metadata)
 
     def validate(self, obj, value):
         if value in self.values:
                 return value
         self.error(obj, value)
 
     def info(self):
         """ Returns a description of the trait."""
         result = 'any of ' + repr(self.values)
         if self.allow_none:
             return result + ' or None'
         return result
 
 class CaselessStrEnum(Enum):
     """An enum of strings that are caseless in validate."""
 
     def validate(self, obj, value):
         if not isinstance(value, py3compat.string_types):
             self.error(obj, value)
 
         for v in self.values:
             if v.lower() == value.lower():
                 return v
         self.error(obj, value)
 
 class Container(Instance):
     """An instance of a container (list, set, etc.)
 
     To be subclassed by overriding klass.
     """
     klass = None
     _cast_types = ()
     _valid_defaults = SequenceTypes
     _trait = None
 
-    def __init__(self, trait=None, default_value=None, allow_none=True,
+    def __init__(self, trait=None, default_value=None, allow_none=False,
                 **metadata):
         """Create a container trait type from a list, set, or tuple.
 
         The default value is created by doing ``List(default_value)``,
         which creates a copy of the ``default_value``.
 
         ``trait`` can be specified, which restricts the type of elements
         in the container to that TraitType.
 
         If only one arg is given and it is not a Trait, it is taken as
         ``default_value``:
 
         ``c = List([1,2,3])``
 
         Parameters
         ----------
 
         trait : TraitType [ optional ]
             the type for restricting the contents of the Container.  If unspecified,
             types are not checked.
 
         default_value : SequenceType [ optional ]
             The default value for the Trait.  Must be list/tuple/set, and
             will be cast to the container type.
 
-        allow_none : Bool [ default True ]
+        allow_none : bool [ default False ]
             Whether to allow the value to be None
 
         **metadata : any
             further keys for extensions to the Trait (e.g. config)
 
         """
         # allow List([values]):
         if default_value is None and not is_trait(trait):
             default_value = trait
             trait = None
 
         if default_value is None:
             args = ()
         elif isinstance(default_value, self._valid_defaults):
             args = (default_value,)
         else:
             raise TypeError('default value of %s was %s' %(self.__class__.__name__, default_value))
 
         if is_trait(trait):
             self._trait = trait() if isinstance(trait, type) else trait
             self._trait.name = 'element'
         elif trait is not None:
             raise TypeError("`trait` must be a Trait or None, got %s"%repr_type(trait))
 
         super(Container,self).__init__(klass=self.klass, args=args,
                                   allow_none=allow_none, **metadata)
 
     def element_error(self, obj, element, validator):
         e = "Element of the '%s' trait of %s instance must be %s, but a value of %s was specified." \
             % (self.name, class_of(obj), validator.info(), repr_type(element))
         raise TraitError(e)
 
     def validate(self, obj, value):
         if isinstance(value, self._cast_types):
             value = self.klass(value)
         value = super(Container, self).validate(obj, value)
         if value is None:
             return value
 
         value = self.validate_elements(obj, value)
 
         return value
 
     def validate_elements(self, obj, value):
         validated = []
         if self._trait is None or isinstance(self._trait, Any):
             return value
         for v in value:
             try:
                 v = self._trait._validate(obj, v)
             except TraitError:
                 self.element_error(obj, v, self._trait)
             else:
                 validated.append(v)
         return self.klass(validated)
 
     def instance_init(self, obj):
         if isinstance(self._trait, TraitType):
             self._trait.this_class = self.this_class
         if hasattr(self._trait, '_resolve_classes'):
             self._trait._resolve_classes()
         super(Container, self).instance_init(obj)
 
 
 class List(Container):
     """An instance of a Python list."""
     klass = list
     _cast_types = (tuple,)
 
-    def __init__(self, trait=None, default_value=None, minlen=0, maxlen=sys.maxsize,
-                allow_none=True, **metadata):
+    def __init__(self, trait=None, default_value=None, minlen=0, maxlen=sys.maxsize, **metadata):
         """Create a List trait type from a list, set, or tuple.
 
         The default value is created by doing ``List(default_value)``,
         which creates a copy of the ``default_value``.
 
         ``trait`` can be specified, which restricts the type of elements
         in the container to that TraitType.
 
         If only one arg is given and it is not a Trait, it is taken as
         ``default_value``:
 
         ``c = List([1,2,3])``
 
         Parameters
         ----------
 
         trait : TraitType [ optional ]
             the type for restricting the contents of the Container.  If unspecified,
             types are not checked.
 
         default_value : SequenceType [ optional ]
             The default value for the Trait.  Must be list/tuple/set, and
             will be cast to the container type.
 
         minlen : Int [ default 0 ]
             The minimum length of the input list
 
         maxlen : Int [ default sys.maxsize ]
             The maximum length of the input list
 
-        allow_none : Bool [ default True ]
+        allow_none : bool [ default False ]
             Whether to allow the value to be None
 
         **metadata : any
             further keys for extensions to the Trait (e.g. config)
 
         """
         self._minlen = minlen
         self._maxlen = maxlen
         super(List, self).__init__(trait=trait, default_value=default_value,
-                                allow_none=allow_none, **metadata)
+                                **metadata)
 
     def length_error(self, obj, value):
         e = "The '%s' trait of %s instance must be of length %i <= L <= %i, but a value of %s was specified." \
             % (self.name, class_of(obj), self._minlen, self._maxlen, value)
         raise TraitError(e)
 
     def validate_elements(self, obj, value):
         length = len(value)
         if length < self._minlen or length > self._maxlen:
             self.length_error(obj, value)
 
         return super(List, self).validate_elements(obj, value)
     
     def validate(self, obj, value):
         value = super(List, self).validate(obj, value)
 
         value = self.validate_elements(obj, value)
 
         return value
         
 
 
 class Set(List):
     """An instance of a Python set."""
     klass = set
     _cast_types = (tuple, list)
 
 class Tuple(Container):
     """An instance of a Python tuple."""
     klass = tuple
     _cast_types = (list,)
 
     def __init__(self, *traits, **metadata):
-        """Tuple(*traits, default_value=None, allow_none=True, **medatata)
+        """Tuple(*traits, default_value=None, **medatata)
 
         Create a tuple from a list, set, or tuple.
 
         Create a fixed-type tuple with Traits:
 
         ``t = Tuple(Int, Str, CStr)``
 
         would be length 3, with Int,Str,CStr for each element.
 
         If only one arg is given and it is not a Trait, it is taken as
         default_value:
 
         ``t = Tuple((1,2,3))``
 
         Otherwise, ``default_value`` *must* be specified by keyword.
 
         Parameters
         ----------
 
         *traits : TraitTypes [ optional ]
             the tsype for restricting the contents of the Tuple.  If unspecified,
             types are not checked. If specified, then each positional argument
             corresponds to an element of the tuple.  Tuples defined with traits
             are of fixed length.
 
         default_value : SequenceType [ optional ]
             The default value for the Tuple.  Must be list/tuple/set, and
             will be cast to a tuple. If `traits` are specified, the
             `default_value` must conform to the shape and type they specify.
 
-        allow_none : Bool [ default True ]
+        allow_none : bool [ default False ]
             Whether to allow the value to be None
 
         **metadata : any
             further keys for extensions to the Trait (e.g. config)
 
         """
         default_value = metadata.pop('default_value', None)
         allow_none = metadata.pop('allow_none', True)
 
         # allow Tuple((values,)):
         if len(traits) == 1 and default_value is None and not is_trait(traits[0]):
             default_value = traits[0]
             traits = ()
 
         if default_value is None:
             args = ()
         elif isinstance(default_value, self._valid_defaults):
             args = (default_value,)
         else:
             raise TypeError('default value of %s was %s' %(self.__class__.__name__, default_value))
 
         self._traits = []
         for trait in traits:
             t = trait() if isinstance(trait, type) else trait
             t.name = 'element'
             self._traits.append(t)
 
         if self._traits and default_value is None:
             # don't allow default to be an empty container if length is specified
             args = None
-        super(Container,self).__init__(klass=self.klass, args=args,
-                                  allow_none=allow_none, **metadata)
+        super(Container,self).__init__(klass=self.klass, args=args, **metadata)
 
     def validate_elements(self, obj, value):
         if not self._traits:
             # nothing to validate
             return value
         if len(value) != len(self._traits):
             e = "The '%s' trait of %s instance requires %i elements, but a value of %s was specified." \
                 % (self.name, class_of(obj), len(self._traits), repr_type(value))
             raise TraitError(e)
 
         validated = []
         for t,v in zip(self._traits, value):
             try:
                 v = t._validate(obj, v)
             except TraitError:
                 self.element_error(obj, v, t)
             else:
                 validated.append(v)
         return tuple(validated)
 
     def instance_init(self, obj):
         for trait in self._traits:
             if isinstance(trait, TraitType):
                 trait.this_class = self.this_class
             if hasattr(trait, '_resolve_classes'):
                 trait._resolve_classes()
         super(Container, self).instance_init(obj)
 
 
 class Dict(Instance):
     """An instance of a Python dict."""
 
-    def __init__(self, default_value={}, allow_none=True, **metadata):
+    def __init__(self, default_value={}, allow_none=False, **metadata):
         """Create a dict trait type from a dict.
 
         The default value is created by doing ``dict(default_value)``,
         which creates a copy of the ``default_value``.
         """
         if default_value is None:
             args = None
         elif isinstance(default_value, dict):
             args = (default_value,)
         elif isinstance(default_value, SequenceTypes):
             args = (default_value,)
         else:
             raise TypeError('default value of Dict was %s' % default_value)
 
         super(Dict,self).__init__(klass=dict, args=args,
                                   allow_none=allow_none, **metadata)
 
 
 class EventfulDict(Instance):
     """An instance of an EventfulDict."""
 
-    def __init__(self, default_value={}, allow_none=True, **metadata):
+    def __init__(self, default_value={}, allow_none=False, **metadata):
         """Create a EventfulDict trait type from a dict.
 
         The default value is created by doing
         ``eventful.EvenfulDict(default_value)``, which creates a copy of the
         ``default_value``.
         """
         if default_value is None:
             args = None
         elif isinstance(default_value, dict):
             args = (default_value,)
         elif isinstance(default_value, SequenceTypes):
             args = (default_value,)
         else:
             raise TypeError('default value of EventfulDict was %s' % default_value)
 
         super(EventfulDict, self).__init__(klass=eventful.EventfulDict, args=args,
                                   allow_none=allow_none, **metadata)
 
 
 class EventfulList(Instance):
     """An instance of an EventfulList."""
 
-    def __init__(self, default_value=None, allow_none=True, **metadata):
+    def __init__(self, default_value=None, allow_none=False, **metadata):
         """Create a EventfulList trait type from a dict.
 
         The default value is created by doing 
         ``eventful.EvenfulList(default_value)``, which creates a copy of the 
         ``default_value``.
         """
         if default_value is None:
             args = ((),)
         else:
             args = (default_value,)
 
         super(EventfulList, self).__init__(klass=eventful.EventfulList, args=args,
                                   allow_none=allow_none, **metadata)
 
 
 class TCPAddress(TraitType):
     """A trait for an (ip, port) tuple.
 
     This allows for both IPv4 IP addresses as well as hostnames.
     """
 
     default_value = ('127.0.0.1', 0)
     info_text = 'an (ip, port) tuple'
 
     def validate(self, obj, value):
         if isinstance(value, tuple):
             if len(value) == 2:
                 if isinstance(value[0], py3compat.string_types) and isinstance(value[1], int):
                     port = value[1]
                     if port >= 0 and port <= 65535:
                         return value
         self.error(obj, value)
 
 class CRegExp(TraitType):
     """A casting compiled regular expression trait.
 
     Accepts both strings and compiled regular expressions. The resulting
     attribute will be a compiled regular expression."""
 
     info_text = 'a regular expression'
 
     def validate(self, obj, value):
         try:
             return re.compile(value)
         except:
             self.error(obj, value)