Try to fix updating classes in Autoreload.

There seem to have been some infinite recursion in the previous version
of the code, so implement a more classical graph finding algorithm.

This should still be properly tested

IPython/extensions/autoreload.py

@@ -1,586 +1,642 b''
 """IPython extension to reload modules before executing user code.
 
 ``autoreload`` reloads modules automatically before entering the execution of
 code typed at the IPython prompt.
 
 This makes for example the following workflow possible:
 
 .. sourcecode:: ipython
 
    In [1]: %load_ext autoreload
 
    In [2]: %autoreload 2
 
    In [3]: from foo import some_function
 
    In [4]: some_function()
    Out[4]: 42
 
    In [5]: # open foo.py in an editor and change some_function to return 43
 
    In [6]: some_function()
    Out[6]: 43
 
 The module was reloaded without reloading it explicitly, and the object
 imported with ``from foo import ...`` was also updated.
 
 Usage
 =====
 
 The following magic commands are provided:
 
 ``%autoreload``
 
     Reload all modules (except those excluded by ``%aimport``)
     automatically now.
 
 ``%autoreload 0``
 
     Disable automatic reloading.
 
 ``%autoreload 1``
 
     Reload all modules imported with ``%aimport`` every time before
     executing the Python code typed.
 
 ``%autoreload 2``
 
     Reload all modules (except those excluded by ``%aimport``) every
     time before executing the Python code typed.
 
 ``%aimport``
 
     List modules which are to be automatically imported or not to be imported.
 
 ``%aimport foo``
 
     Import module 'foo' and mark it to be autoreloaded for ``%autoreload 1``
 
 ``%aimport foo, bar``
 
     Import modules 'foo', 'bar' and mark them to be autoreloaded for ``%autoreload 1``
 
 ``%aimport -foo``
 
     Mark module 'foo' to not be autoreloaded.
 
 Caveats
 =======
 
 Reloading Python modules in a reliable way is in general difficult,
 and unexpected things may occur. ``%autoreload`` tries to work around
 common pitfalls by replacing function code objects and parts of
 classes previously in the module with new versions. This makes the
 following things to work:
 
 - Functions and classes imported via 'from xxx import foo' are upgraded
   to new versions when 'xxx' is reloaded.
 
 - Methods and properties of classes are upgraded on reload, so that
   calling 'c.foo()' on an object 'c' created before the reload causes
   the new code for 'foo' to be executed.
 
 Some of the known remaining caveats are:
 
 - Replacing code objects does not always succeed: changing a @property
   in a class to an ordinary method or a method to a member variable
   can cause problems (but in old objects only).
 
 - Functions that are removed (eg. via monkey-patching) from a module
   before it is reloaded are not upgraded.
 
 - C extension modules cannot be reloaded, and so cannot be autoreloaded.
 """
 
 skip_doctest = True
 
 #-----------------------------------------------------------------------------
 #  Copyright (C) 2000 Thomas Heller
 #  Copyright (C) 2008 Pauli Virtanen <[e-mail]>
 #  Copyright (C) 2012  The IPython Development Team
 #
 #  Distributed under the terms of the BSD License.  The full license is in
 #  the file COPYING, distributed as part of this software.
 #-----------------------------------------------------------------------------
 #
 # This IPython module is written by Pauli Virtanen, based on the autoreload
 # code by Thomas Heller.
 
 #-----------------------------------------------------------------------------
 # Imports
 #-----------------------------------------------------------------------------
 
 import os
 import sys
 import traceback
 import types
 import weakref
 import inspect
 from importlib import import_module
 from importlib.util import source_from_cache
 from imp import reload
 
 #------------------------------------------------------------------------------
 # Autoreload functionality
 #------------------------------------------------------------------------------
 
 class ModuleReloader(object):
     enabled = False
     """Whether this reloader is enabled"""
 
     check_all = True
     """Autoreload all modules, not just those listed in 'modules'"""
 
     def __init__(self):
         # Modules that failed to reload: {module: mtime-on-failed-reload, ...}
         self.failed = {}
         # Modules specially marked as autoreloadable.
         self.modules = {}
         # Modules specially marked as not autoreloadable.
         self.skip_modules = {}
         # (module-name, name) -> weakref, for replacing old code objects
         self.old_objects = {}
         # Module modification timestamps
         self.modules_mtimes = {}
 
         # Cache module modification times
         self.check(check_all=True, do_reload=False)
 
     def mark_module_skipped(self, module_name):
         """Skip reloading the named module in the future"""
         try:
             del self.modules[module_name]
         except KeyError:
             pass
         self.skip_modules[module_name] = True
 
     def mark_module_reloadable(self, module_name):
         """Reload the named module in the future (if it is imported)"""
         try:
             del self.skip_modules[module_name]
         except KeyError:
             pass
         self.modules[module_name] = True
 
     def aimport_module(self, module_name):
         """Import a module, and mark it reloadable
 
         Returns
         -------
         top_module : module
             The imported module if it is top-level, or the top-level
         top_name : module
             Name of top_module
 
         """
         self.mark_module_reloadable(module_name)
 
         import_module(module_name)
         top_name = module_name.split('.')[0]
         top_module = sys.modules[top_name]
         return top_module, top_name
 
     def filename_and_mtime(self, module):
         if not hasattr(module, '__file__') or module.__file__ is None:
             return None, None
 
         if getattr(module, '__name__', None) in [None, '__mp_main__', '__main__']:
             # we cannot reload(__main__) or reload(__mp_main__)
             return None, None
 
         filename = module.__file__
         path, ext = os.path.splitext(filename)
 
         if ext.lower() == '.py':
             py_filename = filename
         else:
             try:
                 py_filename = source_from_cache(filename)
             except ValueError:
                 return None, None
 
         try:
             pymtime = os.stat(py_filename).st_mtime
         except OSError:
             return None, None
 
         return py_filename, pymtime
 
     def check(self, check_all=False, do_reload=True):
         """Check whether some modules need to be reloaded."""
 
         if not self.enabled and not check_all:
             return
 
         if check_all or self.check_all:
             modules = list(sys.modules.keys())
         else:
             modules = list(self.modules.keys())
 
         for modname in modules:
             m = sys.modules.get(modname, None)
 
             if modname in self.skip_modules:
                 continue
 
             py_filename, pymtime = self.filename_and_mtime(m)
             if py_filename is None:
                 continue
 
             try:
                 if pymtime <= self.modules_mtimes[modname]:
                     continue
             except KeyError:
                 self.modules_mtimes[modname] = pymtime
                 continue
             else:
                 if self.failed.get(py_filename, None) == pymtime:
                     continue
 
             self.modules_mtimes[modname] = pymtime
 
             # If we've reached this point, we should try to reload the module
             if do_reload:
                 try:
                     superreload(m, reload, self.old_objects)
                     if py_filename in self.failed:
                         del self.failed[py_filename]
                 except:
                     print("[autoreload of %s failed: %s]" % (
                             modname, traceback.format_exc(10)), file=sys.stderr)
                     self.failed[py_filename] = pymtime
 
 #------------------------------------------------------------------------------
 # superreload
 #------------------------------------------------------------------------------
 
 
 func_attrs = ['__code__', '__defaults__', '__doc__',
               '__closure__', '__globals__', '__dict__']
 
 
 def update_function(old, new):
     """Upgrade the code object of a function"""
     for name in func_attrs:
         try:
             setattr(old, name, getattr(new, name))
         except (AttributeError, TypeError):
             pass
 
 
+def _find_instances(old_type):
+    """Try to find all instances of a class that need updating.
+
+    Classic graph exploration, we want to avoid re-visiting object multiple times.
+    """
+    # find ipython workspace stack frame, this is just to bootstrap where we
+    # find the object that need updating.
+    frame = next(frame_nfo.frame for frame_nfo in inspect.stack()
+                 if 'trigger' in frame_nfo.function)
+    # build generator for non-private variable values from workspace
+    shell = frame.f_locals['self'].shell
+    user_ns = shell.user_ns
+    user_ns_hidden = shell.user_ns_hidden
+    nonmatching = object()
+    objects = ( value for key, value in user_ns.items()
+            if not key.startswith('_')
+            and (value is not user_ns_hidden.get(key, nonmatching))
+            and not inspect.ismodule(value))
+
+    # note:  in the following we do use dict as object might not be hashable.
+    # list of objects we found that will need an update.
+    to_update = {}
+
+    # list of object we have not recursed into yet
+    open_set = {}
+
+    # list of object we have visited already
+    closed_set = {}
+
+    open_set.update({id(o):o for o in objects})
+
+    it = 0
+    while len(open_set) > 0:
+        it += 1
+        if it > 100_000:
+            raise ValueError('infinite')
+        (current_id,current) =  next(iter(open_set.items()))
+        if type(current) is old_type:
+            to_update[current_id] = current
+        if hasattr(current, '__dict__') and not (inspect.isfunction(current)
+                                                 or inspect.ismethod(current)):
+            potential_new = {id(o):o for o in current.__dict__.values() if id(o) not in closed_set.keys()}
+            open_set.update(potential_new)
+        # if object is a container, search it
+        if hasattr(current, 'items') or (hasattr(current, '__contains__')
+                                         and not isinstance(current, str)):
+            potential_new = (value for key, value in current.items()
+                       if not str(key).startswith('_')
+                       and not inspect.ismodule(value) and not id(value) in closed_set.keys())
+            open_set.update(potential_new)
+        del open_set[id(current)]
+        closed_set[id(current)] = current
+    return to_update.values()
+
 def update_instances(old, new, objects=None):
     """Iterate through objects recursively, searching for instances of old and
     replace their __class__ reference with new. If no objects are given, start 
     with the current ipython workspace.
     """
     if not objects:
         # find ipython workspace stack frame
         frame = next(frame_nfo.frame for frame_nfo in inspect.stack() 
                      if 'trigger' in frame_nfo.function)
         # build generator for non-private variable values from workspace
         shell = frame.f_locals['self'].shell
         user_ns = shell.user_ns
         user_ns_hidden = shell.user_ns_hidden
         nonmatching = object()
         objects = ( value for key, value in user_ns.items()
                 if not key.startswith('_') 
                 and (value is not user_ns_hidden.get(key, nonmatching)) 
                 and not inspect.ismodule(value))
     
     # use dict values if objects is a dict but don't touch private variables
     if hasattr(objects, 'items'):
         objects = (value for key, value in objects.items()
                        if not str(key).startswith('_')
                        and not inspect.ismodule(value) )
 
     # try if objects is iterable
     try:
         for obj in objects:
 
             # update, if object is instance of old_class (but no subclasses)
             if type(obj) is old:
                 obj.__class__ = new
                 
 
             # if object is instance of other class, look for nested instances
             if hasattr(obj, '__dict__') and not (inspect.isfunction(obj)
                                                  or inspect.ismethod(obj)):
                 update_instances(old, new, obj.__dict__)
 
             # if object is a container, search it
             if hasattr(obj, 'items') or (hasattr(obj, '__contains__')
                                          and not isinstance(obj, str)):
                 update_instances(old, new, obj)
 
     except TypeError:
         pass
 
         
 def update_class(old, new):
     """Replace stuff in the __dict__ of a class, and upgrade
     method code objects, and add new methods, if any"""
+    print('old is', old)
     for key in list(old.__dict__.keys()):
         old_obj = getattr(old, key)
         try:
             new_obj = getattr(new, key)
             # explicitly checking that comparison returns True to handle
             # cases where `==` doesn't return a boolean.
             if (old_obj == new_obj) is True:
                 continue
         except AttributeError:
             # obsolete attribute: remove it
             try:
                 delattr(old, key)
             except (AttributeError, TypeError):
                 pass
             continue
 
         if update_generic(old_obj, new_obj): continue
 
         try:
             setattr(old, key, getattr(new, key))
         except (AttributeError, TypeError):
             pass # skip non-writable attributes
 
     for key in list(new.__dict__.keys()):
         if key not in list(old.__dict__.keys()):
             try:
                 setattr(old, key, getattr(new, key))
             except (AttributeError, TypeError):
                 pass # skip non-writable attributes
 
     # update all instances of class
-    update_instances(old, new)
+    for instance in _find_instances(old):
+        instance.__class__ = new
 
 
 def update_property(old, new):
     """Replace get/set/del functions of a property"""
     update_generic(old.fdel, new.fdel)
     update_generic(old.fget, new.fget)
     update_generic(old.fset, new.fset)
 
 
 def isinstance2(a, b, typ):
     return isinstance(a, typ) and isinstance(b, typ)
 
 
 UPDATE_RULES = [
     (lambda a, b: isinstance2(a, b, type),
      update_class),
     (lambda a, b: isinstance2(a, b, types.FunctionType),
      update_function),
     (lambda a, b: isinstance2(a, b, property),
      update_property),
 ]
 UPDATE_RULES.extend([(lambda a, b: isinstance2(a, b, types.MethodType),
                       lambda a, b: update_function(a.__func__, b.__func__)),
 ])
 
 
 def update_generic(a, b):
     for type_check, update in UPDATE_RULES:
         if type_check(a, b):
             update(a, b)
             return True
     return False
 
 
 class StrongRef(object):
     def __init__(self, obj):
         self.obj = obj
     def __call__(self):
         return self.obj
 
 
 def superreload(module, reload=reload, old_objects=None):
     """Enhanced version of the builtin reload function.
 
     superreload remembers objects previously in the module, and
 
     - upgrades the class dictionary of every old class in the module
     - upgrades the code object of every old function and method
     - clears the module's namespace before reloading
 
     """
     if old_objects is None:
         old_objects = {}
 
     # collect old objects in the module
     for name, obj in list(module.__dict__.items()):
         if not hasattr(obj, '__module__') or obj.__module__ != module.__name__:
             continue
         key = (module.__name__, name)
         try:
             old_objects.setdefault(key, []).append(weakref.ref(obj))
         except TypeError:
             pass
 
     # reload module
     try:
         # clear namespace first from old cruft
         old_dict = module.__dict__.copy()
         old_name = module.__name__
         module.__dict__.clear()
         module.__dict__['__name__'] = old_name
         module.__dict__['__loader__'] = old_dict['__loader__']
     except (TypeError, AttributeError, KeyError):
         pass
 
     try:
         module = reload(module)
     except:
         # restore module dictionary on failed reload
         module.__dict__.update(old_dict)
         raise
 
     # iterate over all objects and update functions & classes
     for name, new_obj in list(module.__dict__.items()):
         key = (module.__name__, name)
         if key not in old_objects: continue
 
         new_refs = []
         for old_ref in old_objects[key]:
             old_obj = old_ref()
             if old_obj is None: continue
             new_refs.append(old_ref)
             update_generic(old_obj, new_obj)
 
         if new_refs:
             old_objects[key] = new_refs
         else:
             del old_objects[key]
 
     return module
 
 #------------------------------------------------------------------------------
 # IPython connectivity
 #------------------------------------------------------------------------------
 
 from IPython.core.magic import Magics, magics_class, line_magic
 
 @magics_class
 class AutoreloadMagics(Magics):
     def __init__(self, *a, **kw):
         super(AutoreloadMagics, self).__init__(*a, **kw)
         self._reloader = ModuleReloader()
         self._reloader.check_all = False
         self.loaded_modules = set(sys.modules)
 
     @line_magic
     def autoreload(self, parameter_s=''):
         r"""%autoreload => Reload modules automatically
 
         %autoreload
         Reload all modules (except those excluded by %aimport) automatically
         now.
 
         %autoreload 0
         Disable automatic reloading.
 
         %autoreload 1
         Reload all modules imported with %aimport every time before executing
         the Python code typed.
 
         %autoreload 2
         Reload all modules (except those excluded by %aimport) every time
         before executing the Python code typed.
 
         Reloading Python modules in a reliable way is in general
         difficult, and unexpected things may occur. %autoreload tries to
         work around common pitfalls by replacing function code objects and
         parts of classes previously in the module with new versions. This
         makes the following things to work:
 
         - Functions and classes imported via 'from xxx import foo' are upgraded
           to new versions when 'xxx' is reloaded.
 
         - Methods and properties of classes are upgraded on reload, so that
           calling 'c.foo()' on an object 'c' created before the reload causes
           the new code for 'foo' to be executed.
 
         Some of the known remaining caveats are:
 
         - Replacing code objects does not always succeed: changing a @property
           in a class to an ordinary method or a method to a member variable
           can cause problems (but in old objects only).
 
         - Functions that are removed (eg. via monkey-patching) from a module
           before it is reloaded are not upgraded.
 
         - C extension modules cannot be reloaded, and so cannot be
           autoreloaded.
 
         """
         if parameter_s == '':
             self._reloader.check(True)
         elif parameter_s == '0':
             self._reloader.enabled = False
         elif parameter_s == '1':
             self._reloader.check_all = False
             self._reloader.enabled = True
         elif parameter_s == '2':
             self._reloader.check_all = True
             self._reloader.enabled = True
 
     @line_magic
     def aimport(self, parameter_s='', stream=None):
         """%aimport => Import modules for automatic reloading.
 
         %aimport
         List modules to automatically import and not to import.
 
         %aimport foo
         Import module 'foo' and mark it to be autoreloaded for %autoreload 1
 
         %aimport foo, bar
         Import modules 'foo', 'bar' and mark them to be autoreloaded for %autoreload 1
 
         %aimport -foo
         Mark module 'foo' to not be autoreloaded for %autoreload 1
         """
         modname = parameter_s
         if not modname:
             to_reload = sorted(self._reloader.modules.keys())
             to_skip = sorted(self._reloader.skip_modules.keys())
             if stream is None:
                 stream = sys.stdout
             if self._reloader.check_all:
                 stream.write("Modules to reload:\nall-except-skipped\n")
             else:
                 stream.write("Modules to reload:\n%s\n" % ' '.join(to_reload))
             stream.write("\nModules to skip:\n%s\n" % ' '.join(to_skip))
         elif modname.startswith('-'):
             modname = modname[1:]
             self._reloader.mark_module_skipped(modname)
         else:
             for _module in ([_.strip() for _ in modname.split(',')]):
                 top_module, top_name = self._reloader.aimport_module(_module)
 
                 # Inject module to user namespace
                 self.shell.push({top_name: top_module})
 
     def pre_run_cell(self):
         if self._reloader.enabled:
             try:
                 self._reloader.check()
             except:
                 pass
 
     def post_execute_hook(self):
         """Cache the modification times of any modules imported in this execution
         """
         newly_loaded_modules = set(sys.modules) - self.loaded_modules
         for modname in newly_loaded_modules:
             _, pymtime = self._reloader.filename_and_mtime(sys.modules[modname])
             if pymtime is not None:
                 self._reloader.modules_mtimes[modname] = pymtime
 
         self.loaded_modules.update(newly_loaded_modules)
 
 
 def load_ipython_extension(ip):
     """Load the extension in IPython."""
     auto_reload = AutoreloadMagics(ip)
     ip.register_magics(auto_reload)
     ip.events.register('pre_run_cell', auto_reload.pre_run_cell)
     ip.events.register('post_execute', auto_reload.post_execute_hook)

IPython/extensions/tests/test_autoreload.py

@@ -1,398 +1,400 b''
 """Tests for autoreload extension.
 """
 #-----------------------------------------------------------------------------
 #  Copyright (c) 2012 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
 #-----------------------------------------------------------------------------
 
 import os
 import sys
 import tempfile
 import textwrap
 import shutil
 import random
 import time
 from io import StringIO
 
 import nose.tools as nt
 import IPython.testing.tools as tt
 
 from IPython.testing.decorators import skipif
 
 from IPython.extensions.autoreload import AutoreloadMagics
 from IPython.core.events import EventManager, pre_run_cell
 
 #-----------------------------------------------------------------------------
 # Test fixture
 #-----------------------------------------------------------------------------
 
 noop = lambda *a, **kw: None
 
-class FakeShell(object):
+class FakeShell:
 
     def __init__(self):
         self.ns = {}
+        self.user_ns = {}
+        self.user_ns_hidden = {}
         self.events = EventManager(self, {'pre_run_cell', pre_run_cell})
         self.auto_magics = AutoreloadMagics(shell=self)
         self.events.register('pre_run_cell', self.auto_magics.pre_run_cell)
 
     register_magics = set_hook = noop
 
     def run_code(self, code):
         self.events.trigger('pre_run_cell')
         exec(code, self.ns)
         self.auto_magics.post_execute_hook()
 
     def push(self, items):
         self.ns.update(items)
 
     def magic_autoreload(self, parameter):
         self.auto_magics.autoreload(parameter)
 
     def magic_aimport(self, parameter, stream=None):
         self.auto_magics.aimport(parameter, stream=stream)
         self.auto_magics.post_execute_hook()
 
 
 class Fixture(object):
     """Fixture for creating test module files"""
 
     test_dir = None
     old_sys_path = None
     filename_chars = "abcdefghijklmopqrstuvwxyz0123456789"
 
     def setUp(self):
         self.test_dir = tempfile.mkdtemp()
         self.old_sys_path = list(sys.path)
         sys.path.insert(0, self.test_dir)
         self.shell = FakeShell()
 
     def tearDown(self):
         shutil.rmtree(self.test_dir)
         sys.path = self.old_sys_path
 
         self.test_dir = None
         self.old_sys_path = None
         self.shell = None
 
     def get_module(self):
         module_name = "tmpmod_" + "".join(random.sample(self.filename_chars,20))
         if module_name in sys.modules:
             del sys.modules[module_name]
         file_name = os.path.join(self.test_dir, module_name + ".py")
         return module_name, file_name
 
     def write_file(self, filename, content):
         """
         Write a file, and force a timestamp difference of at least one second
 
         Notes
         -----
         Python's .pyc files record the timestamp of their compilation
         with a time resolution of one second.
 
         Therefore, we need to force a timestamp difference between .py
         and .pyc, without having the .py file be timestamped in the
         future, and without changing the timestamp of the .pyc file
         (because that is stored in the file).  The only reliable way
         to achieve this seems to be to sleep.
         """
 
         # Sleep one second + eps
         time.sleep(1.05)
 
         # Write
         with open(filename, 'w') as f:
             f.write(content)
 
     def new_module(self, code):
         mod_name, mod_fn = self.get_module()
         with open(mod_fn, 'w') as f:
             f.write(code)
         return mod_name, mod_fn
 
 #-----------------------------------------------------------------------------
 # Test automatic reloading
 #-----------------------------------------------------------------------------
 
 class TestAutoreload(Fixture):
 
     @skipif(sys.version_info < (3, 6))
     def test_reload_enums(self):
         import enum
         mod_name, mod_fn = self.new_module(textwrap.dedent("""
                                 from enum import Enum
                                 class MyEnum(Enum):
                                     A = 'A'
                                     B = 'B'
                             """))
         self.shell.magic_autoreload("2")
         self.shell.magic_aimport(mod_name)
         self.write_file(mod_fn, textwrap.dedent("""
                                 from enum import Enum
                                 class MyEnum(Enum):
                                     A = 'A'
                                     B = 'B'
                                     C = 'C'
                             """))
         with tt.AssertNotPrints(('[autoreload of %s failed:' % mod_name), channel='stderr'):
             self.shell.run_code("pass")  # trigger another reload
 
     def test_reload_class_attributes(self):
         self.shell.magic_autoreload("2")
         mod_name, mod_fn = self.new_module(textwrap.dedent("""
                                 class MyClass:
 
                                     def __init__(self, a=10):
                                         self.a = a
                                         self.b = 22 
                                         # self.toto = 33
 
                                     def square(self):
                                         print('compute square')
                                         return self.a*self.a
                             """
             )
         )
         self.shell.run_code("from %s import MyClass" % mod_name)
         self.shell.run_code("first = MyClass(5)")
         self.shell.run_code("first.square()")
         with nt.assert_raises(AttributeError):
             self.shell.run_code("first.cube()")
         with nt.assert_raises(AttributeError):
             self.shell.run_code("first.power(5)")
         self.shell.run_code("first.b")
         with nt.assert_raises(AttributeError):
             self.shell.run_code("first.toto")
 
         # remove square, add power
 
         self.write_file(
             mod_fn,
             textwrap.dedent(
                 """
                             class MyClass:
 
                                 def __init__(self, a=10):
                                     self.a = a
                                     self.b = 11
 
                                 def power(self, p):
                                     print('compute power '+str(p))
                                     return self.a**p
                             """
             ),
         )
 
         self.shell.run_code("second = MyClass(5)")
 
         for object_name in {'first', 'second'}:
             self.shell.run_code("{object_name}.power(5)".format(object_name=object_name))
             with nt.assert_raises(AttributeError):
                 self.shell.run_code("{object_name}.cube()".format(object_name=object_name))
             with nt.assert_raises(AttributeError):
                 self.shell.run_code("{object_name}.square()".format(object_name=object_name))
             self.shell.run_code("{object_name}.b".format(object_name=object_name))
             self.shell.run_code("{object_name}.a".format(object_name=object_name))
             with nt.assert_raises(AttributeError):
                 self.shell.run_code("{object_name}.toto".format(object_name=object_name))
 
     def _check_smoketest(self, use_aimport=True):
         """
         Functional test for the automatic reloader using either
         '%autoreload 1' or '%autoreload 2'
         """
 
         mod_name, mod_fn = self.new_module("""
 x = 9
 
 z = 123  # this item will be deleted
 
 def foo(y):
     return y + 3
 
 class Baz(object):
     def __init__(self, x):
         self.x = x
     def bar(self, y):
         return self.x + y
     @property
     def quux(self):
         return 42
     def zzz(self):
         '''This method will be deleted below'''
         return 99
 
 class Bar:    # old-style class: weakref doesn't work for it on Python < 2.7
     def foo(self):
         return 1
 """)
 
         #
         # Import module, and mark for reloading
         #
         if use_aimport:
             self.shell.magic_autoreload("1")
             self.shell.magic_aimport(mod_name)
             stream = StringIO()
             self.shell.magic_aimport("", stream=stream)
             nt.assert_in(("Modules to reload:\n%s" % mod_name), stream.getvalue())
 
             with nt.assert_raises(ImportError):
                 self.shell.magic_aimport("tmpmod_as318989e89ds")
         else:
             self.shell.magic_autoreload("2")
             self.shell.run_code("import %s" % mod_name)
             stream = StringIO()
             self.shell.magic_aimport("", stream=stream)
             nt.assert_true("Modules to reload:\nall-except-skipped" in
                            stream.getvalue())
         nt.assert_in(mod_name, self.shell.ns)
 
         mod = sys.modules[mod_name]
 
         #
         # Test module contents
         #
         old_foo = mod.foo
         old_obj = mod.Baz(9)
         old_obj2 = mod.Bar()
 
         def check_module_contents():
             nt.assert_equal(mod.x, 9)
             nt.assert_equal(mod.z, 123)
 
             nt.assert_equal(old_foo(0), 3)
             nt.assert_equal(mod.foo(0), 3)
 
             obj = mod.Baz(9)
             nt.assert_equal(old_obj.bar(1), 10)
             nt.assert_equal(obj.bar(1), 10)
             nt.assert_equal(obj.quux, 42)
             nt.assert_equal(obj.zzz(), 99)
 
             obj2 = mod.Bar()
             nt.assert_equal(old_obj2.foo(), 1)
             nt.assert_equal(obj2.foo(), 1)
 
         check_module_contents()
 
         #
         # Simulate a failed reload: no reload should occur and exactly
         # one error message should be printed
         #
         self.write_file(mod_fn, """
 a syntax error
 """)
 
         with tt.AssertPrints(('[autoreload of %s failed:' % mod_name), channel='stderr'):
             self.shell.run_code("pass") # trigger reload
         with tt.AssertNotPrints(('[autoreload of %s failed:' % mod_name), channel='stderr'):
             self.shell.run_code("pass") # trigger another reload
         check_module_contents()
 
         #
         # Rewrite module (this time reload should succeed)
         #
         self.write_file(mod_fn, """
 x = 10
 
 def foo(y):
     return y + 4
 
 class Baz(object):
     def __init__(self, x):
         self.x = x
     def bar(self, y):
         return self.x + y + 1
     @property
     def quux(self):
         return 43
 
 class Bar:    # old-style class
     def foo(self):
         return 2
 """)
 
         def check_module_contents():
             nt.assert_equal(mod.x, 10)
             nt.assert_false(hasattr(mod, 'z'))
 
             nt.assert_equal(old_foo(0), 4) # superreload magic!
             nt.assert_equal(mod.foo(0), 4)
 
             obj = mod.Baz(9)
             nt.assert_equal(old_obj.bar(1), 11) # superreload magic!
             nt.assert_equal(obj.bar(1), 11)
 
             nt.assert_equal(old_obj.quux, 43)
             nt.assert_equal(obj.quux, 43)
 
             nt.assert_false(hasattr(old_obj, 'zzz'))
             nt.assert_false(hasattr(obj, 'zzz'))
 
             obj2 = mod.Bar()
             nt.assert_equal(old_obj2.foo(), 2)
             nt.assert_equal(obj2.foo(), 2)
 
         self.shell.run_code("pass") # trigger reload
         check_module_contents()
 
         #
         # Another failure case: deleted file (shouldn't reload)
         #
         os.unlink(mod_fn)
 
         self.shell.run_code("pass") # trigger reload
         check_module_contents()
 
         #
         # Disable autoreload and rewrite module: no reload should occur
         #
         if use_aimport:
             self.shell.magic_aimport("-" + mod_name)
             stream = StringIO()
             self.shell.magic_aimport("", stream=stream)
             nt.assert_true(("Modules to skip:\n%s" % mod_name) in
                            stream.getvalue())
 
             # This should succeed, although no such module exists
             self.shell.magic_aimport("-tmpmod_as318989e89ds")
         else:
             self.shell.magic_autoreload("0")
 
         self.write_file(mod_fn, """
 x = -99
 """)
 
         self.shell.run_code("pass") # trigger reload
         self.shell.run_code("pass")
         check_module_contents()
 
         #
         # Re-enable autoreload: reload should now occur
         #
         if use_aimport:
             self.shell.magic_aimport(mod_name)
         else:
             self.shell.magic_autoreload("")
 
         self.shell.run_code("pass") # trigger reload
         nt.assert_equal(mod.x, -99)
 
     def test_smoketest_aimport(self):
         self._check_smoketest(use_aimport=True)
 
     def test_smoketest_autoreload(self):
         self._check_smoketest(use_aimport=False)