MAINT: Remove usage of traitlets.

Now this is mostly validate at typechecheck time, instead of runtime.
We don't use any validation logic so I'm unsure it is really necessary.

IPython/core/application.py

@@ -1,489 +1,488 b''
 # encoding: utf-8
 """
 An application for IPython.
 
 All top-level applications should use the classes in this module for
 handling configuration and creating configurables.
 
 The job of an :class:`Application` is to create the master configuration
 object and then create the configurable objects, passing the config to them.
 """
 
 # Copyright (c) IPython Development Team.
 # Distributed under the terms of the Modified BSD License.
 
 import atexit
 from copy import deepcopy
 import logging
 import os
 import shutil
 import sys
 
 from pathlib import Path
 
 from traitlets.config.application import Application, catch_config_error
 from traitlets.config.loader import ConfigFileNotFound, PyFileConfigLoader
 from IPython.core import release, crashhandler
 from IPython.core.profiledir import ProfileDir, ProfileDirError
 from IPython.paths import get_ipython_dir, get_ipython_package_dir
 from IPython.utils.path import ensure_dir_exists
 from traitlets import (
     List, Unicode, Type, Bool, Set, Instance, Undefined,
     default, observe,
 )
 
 if os.name == "nt":
     programdata = os.environ.get("PROGRAMDATA", None)
     if programdata is not None:
         SYSTEM_CONFIG_DIRS = [str(Path(programdata) / "ipython")]
     else:  # PROGRAMDATA is not defined by default on XP.
         SYSTEM_CONFIG_DIRS = []
 else:
     SYSTEM_CONFIG_DIRS = [
         "/usr/local/etc/ipython",
         "/etc/ipython",
     ]
 
 
 ENV_CONFIG_DIRS = []
 _env_config_dir = os.path.join(sys.prefix, 'etc', 'ipython')
 if _env_config_dir not in SYSTEM_CONFIG_DIRS:
     # only add ENV_CONFIG if sys.prefix is not already included
     ENV_CONFIG_DIRS.append(_env_config_dir)
 
 
 _envvar = os.environ.get('IPYTHON_SUPPRESS_CONFIG_ERRORS')
 if _envvar in {None, ''}:
     IPYTHON_SUPPRESS_CONFIG_ERRORS = None
 else:
     if _envvar.lower() in {'1','true'}:
         IPYTHON_SUPPRESS_CONFIG_ERRORS = True
     elif _envvar.lower() in {'0','false'} :
         IPYTHON_SUPPRESS_CONFIG_ERRORS = False
     else:
         sys.exit("Unsupported value for environment variable: 'IPYTHON_SUPPRESS_CONFIG_ERRORS' is set to '%s' which is none of  {'0', '1', 'false', 'true', ''}."% _envvar )
 
 # aliases and flags
 
 base_aliases = {}
 if isinstance(Application.aliases, dict):
     # traitlets 5
     base_aliases.update(Application.aliases)
 base_aliases.update(
     {
         "profile-dir": "ProfileDir.location",
         "profile": "BaseIPythonApplication.profile",
         "ipython-dir": "BaseIPythonApplication.ipython_dir",
         "log-level": "Application.log_level",
         "config": "BaseIPythonApplication.extra_config_file",
     }
 )
 
 base_flags = dict()
 if isinstance(Application.flags, dict):
     # traitlets 5
     base_flags.update(Application.flags)
 base_flags.update(
     dict(
         debug=(
             {"Application": {"log_level": logging.DEBUG}},
             "set log level to logging.DEBUG (maximize logging output)",
         ),
         quiet=(
             {"Application": {"log_level": logging.CRITICAL}},
             "set log level to logging.CRITICAL (minimize logging output)",
         ),
         init=(
             {
                 "BaseIPythonApplication": {
                     "copy_config_files": True,
                     "auto_create": True,
                 }
             },
             """Initialize profile with default config files.  This is equivalent
             to running `ipython profile create <profile>` prior to startup.
             """,
         ),
     )
 )
 
 
 class ProfileAwareConfigLoader(PyFileConfigLoader):
     """A Python file config loader that is aware of IPython profiles."""
     def load_subconfig(self, fname, path=None, profile=None):
         if profile is not None:
             try:
                 profile_dir = ProfileDir.find_profile_dir_by_name(
                         get_ipython_dir(),
                         profile,
                 )
             except ProfileDirError:
                 return
             path = profile_dir.location
         return super(ProfileAwareConfigLoader, self).load_subconfig(fname, path=path)
 
 class BaseIPythonApplication(Application):
-
-    name = u'ipython'
-    description = Unicode(u'IPython: an enhanced interactive Python shell.')
+    name = "ipython"
+    description = "IPython: an enhanced interactive Python shell."
     version = Unicode(release.version)
 
     aliases = base_aliases
     flags = base_flags
     classes = List([ProfileDir])
     
     # enable `load_subconfig('cfg.py', profile='name')`
     python_config_loader_class = ProfileAwareConfigLoader
 
     # Track whether the config_file has changed,
     # because some logic happens only if we aren't using the default.
     config_file_specified = Set()
 
     config_file_name = Unicode()
     @default('config_file_name')
     def _config_file_name_default(self):
         return self.name.replace('-','_') + u'_config.py'
     @observe('config_file_name')
     def _config_file_name_changed(self, change):
         if change['new'] != change['old']:
             self.config_file_specified.add(change['new'])
 
     # The directory that contains IPython's builtin profiles.
     builtin_profile_dir = Unicode(
         os.path.join(get_ipython_package_dir(), u'config', u'profile', u'default')
     )
     
     config_file_paths = List(Unicode())
     @default('config_file_paths')
     def _config_file_paths_default(self):
         return []
 
     extra_config_file = Unicode(
     help="""Path to an extra config file to load.
     
     If specified, load this config file in addition to any other IPython config.
     """).tag(config=True)
     @observe('extra_config_file')
     def _extra_config_file_changed(self, change):
         old = change['old']
         new = change['new']
         try:
             self.config_files.remove(old)
         except ValueError:
             pass
         self.config_file_specified.add(new)
         self.config_files.append(new)
 
     profile = Unicode(u'default',
         help="""The IPython profile to use."""
     ).tag(config=True)
     
     @observe('profile')
     def _profile_changed(self, change):
         self.builtin_profile_dir = os.path.join(
                 get_ipython_package_dir(), u'config', u'profile', change['new']
         )
 
     add_ipython_dir_to_sys_path = Bool(
         False,
         """Should the IPython profile directory be added to sys path ?
 
         This option was non-existing before IPython 8.0, and ipython_dir was added to
         sys path to allow import of extensions present there. This was historical
         baggage from when pip did not exist. This now default to false,
         but can be set to true for legacy reasons.
         """,
     ).tag(config=True)
 
     ipython_dir = Unicode(
         help="""
         The name of the IPython directory. This directory is used for logging
         configuration (through profiles), history storage, etc. The default
         is usually $HOME/.ipython. This option can also be specified through
         the environment variable IPYTHONDIR.
         """
     ).tag(config=True)
     @default('ipython_dir')
     def _ipython_dir_default(self):
         d = get_ipython_dir()
         self._ipython_dir_changed({
             'name': 'ipython_dir',
             'old': d,
             'new': d,
         })
         return d
     
     _in_init_profile_dir = False
     profile_dir = Instance(ProfileDir, allow_none=True)
     @default('profile_dir')
     def _profile_dir_default(self):
         # avoid recursion
         if self._in_init_profile_dir:
             return
         # profile_dir requested early, force initialization
         self.init_profile_dir()
         return self.profile_dir
 
     overwrite = Bool(False,
         help="""Whether to overwrite existing config files when copying"""
     ).tag(config=True)
     auto_create = Bool(False,
         help="""Whether to create profile dir if it doesn't exist"""
     ).tag(config=True)
 
     config_files = List(Unicode())
     @default('config_files')
     def _config_files_default(self):
         return [self.config_file_name]
 
     copy_config_files = Bool(False,
         help="""Whether to install the default config files into the profile dir.
         If a new profile is being created, and IPython contains config files for that
         profile, then they will be staged into the new directory.  Otherwise,
         default config files will be automatically generated.
         """).tag(config=True)
     
     verbose_crash = Bool(False,
         help="""Create a massive crash report when IPython encounters what may be an
         internal error.  The default is to append a short message to the
         usual traceback""").tag(config=True)
 
     # The class to use as the crash handler.
     crash_handler_class = Type(crashhandler.CrashHandler)
 
     @catch_config_error
     def __init__(self, **kwargs):
         super(BaseIPythonApplication, self).__init__(**kwargs)
         # ensure current working directory exists
         try:
             os.getcwd()
         except:
             # exit if cwd doesn't exist
             self.log.error("Current working directory doesn't exist.")
             self.exit(1)
 
     #-------------------------------------------------------------------------
     # Various stages of Application creation
     #-------------------------------------------------------------------------
     
     def init_crash_handler(self):
         """Create a crash handler, typically setting sys.excepthook to it."""
         self.crash_handler = self.crash_handler_class(self)
         sys.excepthook = self.excepthook
         def unset_crashhandler():
             sys.excepthook = sys.__excepthook__
         atexit.register(unset_crashhandler)
     
     def excepthook(self, etype, evalue, tb):
         """this is sys.excepthook after init_crashhandler
 
         set self.verbose_crash=True to use our full crashhandler, instead of
         a regular traceback with a short message (crash_handler_lite)
         """
         
         if self.verbose_crash:
             return self.crash_handler(etype, evalue, tb)
         else:
             return crashhandler.crash_handler_lite(etype, evalue, tb)
 
     @observe('ipython_dir')
     def _ipython_dir_changed(self, change):
         old = change['old']
         new = change['new']
         if old is not Undefined:
             str_old = os.path.abspath(old)
             if str_old in sys.path:
                 sys.path.remove(str_old)
         if self.add_ipython_dir_to_sys_path:
             str_path = os.path.abspath(new)
             sys.path.append(str_path)
             ensure_dir_exists(new)
             readme = os.path.join(new, "README")
             readme_src = os.path.join(
                 get_ipython_package_dir(), "config", "profile", "README"
             )
             if not os.path.exists(readme) and os.path.exists(readme_src):
                 shutil.copy(readme_src, readme)
             for d in ("extensions", "nbextensions"):
                 path = os.path.join(new, d)
                 try:
                     ensure_dir_exists(path)
                 except OSError as e:
                     # this will not be EEXIST
                     self.log.error("couldn't create path %s: %s", path, e)
             self.log.debug("IPYTHONDIR set to: %s" % new)
 
     def load_config_file(self, suppress_errors=IPYTHON_SUPPRESS_CONFIG_ERRORS):
         """Load the config file.
 
         By default, errors in loading config are handled, and a warning
         printed on screen. For testing, the suppress_errors option is set
         to False, so errors will make tests fail.
 
         `suppress_errors` default value is to be `None` in which case the
         behavior default to the one of `traitlets.Application`.
 
         The default value can be set :
            - to `False` by setting 'IPYTHON_SUPPRESS_CONFIG_ERRORS' environment variable to '0', or 'false' (case insensitive).
            - to `True` by setting 'IPYTHON_SUPPRESS_CONFIG_ERRORS' environment variable to '1' or 'true' (case insensitive).
            - to `None` by setting 'IPYTHON_SUPPRESS_CONFIG_ERRORS' environment variable to '' (empty string) or leaving it unset.
 
         Any other value are invalid, and will make IPython exit with a non-zero return code.
         """
 
 
         self.log.debug("Searching path %s for config files", self.config_file_paths)
         base_config = 'ipython_config.py'
         self.log.debug("Attempting to load config file: %s" %
                        base_config)
         try:
             if suppress_errors is not None:
                 old_value = Application.raise_config_file_errors
                 Application.raise_config_file_errors = not suppress_errors;
             Application.load_config_file(
                 self,
                 base_config,
                 path=self.config_file_paths
             )
         except ConfigFileNotFound:
             # ignore errors loading parent
             self.log.debug("Config file %s not found", base_config)
             pass
         if suppress_errors is not None:
             Application.raise_config_file_errors = old_value
         
         for config_file_name in self.config_files:
             if not config_file_name or config_file_name == base_config:
                 continue
             self.log.debug("Attempting to load config file: %s" %
                            self.config_file_name)
             try:
                 Application.load_config_file(
                     self,
                     config_file_name,
                     path=self.config_file_paths
                 )
             except ConfigFileNotFound:
                 # Only warn if the default config file was NOT being used.
                 if config_file_name in self.config_file_specified:
                     msg = self.log.warning
                 else:
                     msg = self.log.debug
                 msg("Config file not found, skipping: %s", config_file_name)
             except Exception:
                 # For testing purposes.
                 if not suppress_errors:
                     raise
                 self.log.warning("Error loading config file: %s" %
                               self.config_file_name, exc_info=True)
 
     def init_profile_dir(self):
         """initialize the profile dir"""
         self._in_init_profile_dir = True
         if self.profile_dir is not None:
             # already ran
             return
         if 'ProfileDir.location' not in self.config:
             # location not specified, find by profile name
             try:
                 p = ProfileDir.find_profile_dir_by_name(self.ipython_dir, self.profile, self.config)
             except ProfileDirError:
                 # not found, maybe create it (always create default profile)
                 if self.auto_create or self.profile == 'default':
                     try:
                         p = ProfileDir.create_profile_dir_by_name(self.ipython_dir, self.profile, self.config)
                     except ProfileDirError:
                         self.log.fatal("Could not create profile: %r"%self.profile)
                         self.exit(1)
                     else:
                         self.log.info("Created profile dir: %r"%p.location)
                 else:
                     self.log.fatal("Profile %r not found."%self.profile)
                     self.exit(1)
             else:
                 self.log.debug(f"Using existing profile dir: {p.location!r}")
         else:
             location = self.config.ProfileDir.location
             # location is fully specified
             try:
                 p = ProfileDir.find_profile_dir(location, self.config)
             except ProfileDirError:
                 # not found, maybe create it
                 if self.auto_create:
                     try:
                         p = ProfileDir.create_profile_dir(location, self.config)
                     except ProfileDirError:
                         self.log.fatal("Could not create profile directory: %r"%location)
                         self.exit(1)
                     else:
                         self.log.debug("Creating new profile dir: %r"%location)
                 else:
                     self.log.fatal("Profile directory %r not found."%location)
                     self.exit(1)
             else:
                 self.log.debug(f"Using existing profile dir: {p.location!r}")
             # if profile_dir is specified explicitly, set profile name
             dir_name = os.path.basename(p.location)
             if dir_name.startswith('profile_'):
                 self.profile = dir_name[8:]
 
         self.profile_dir = p
         self.config_file_paths.append(p.location)
         self._in_init_profile_dir = False
 
     def init_config_files(self):
         """[optionally] copy default config files into profile dir."""
         self.config_file_paths.extend(ENV_CONFIG_DIRS)
         self.config_file_paths.extend(SYSTEM_CONFIG_DIRS)
         # copy config files
         path = Path(self.builtin_profile_dir)
         if self.copy_config_files:
             src = self.profile
 
             cfg = self.config_file_name
             if path and (path / cfg).exists():
                 self.log.warning(
                     "Staging %r from %s into %r [overwrite=%s]"
                     % (cfg, src, self.profile_dir.location, self.overwrite)
                 )
                 self.profile_dir.copy_config_file(cfg, path=path, overwrite=self.overwrite)
             else:
                 self.stage_default_config_file()
         else:
             # Still stage *bundled* config files, but not generated ones
             # This is necessary for `ipython profile=sympy` to load the profile
             # on the first go
             files = path.glob("*.py")
             for fullpath in files:
                 cfg = fullpath.name
                 if self.profile_dir.copy_config_file(cfg, path=path, overwrite=False):
                     # file was copied
                     self.log.warning("Staging bundled %s from %s into %r"%(
                             cfg, self.profile, self.profile_dir.location)
                     )
 
 
     def stage_default_config_file(self):
         """auto generate default config file, and stage it into the profile."""
         s = self.generate_config_file()
         config_file = Path(self.profile_dir.location) / self.config_file_name
         if self.overwrite or not config_file.exists():
             self.log.warning("Generating default config file: %r" % (config_file))
             config_file.write_text(s, encoding="utf-8")
 
     @catch_config_error
     def initialize(self, argv=None):
         # don't hook up crash handler before parsing command-line
         self.parse_command_line(argv)
         self.init_crash_handler()
         if self.subapp is not None:
             # stop here if subapp is taking over
             return
         # save a copy of CLI config to re-load after config files
         # so that it has highest priority
         cl_config = deepcopy(self.config)
         self.init_profile_dir()
         self.init_config_files()
         self.load_config_file()
         # enforce cl-opts override configfile opts:
         self.update_config(cl_config)