Increase coverage of `guard_eval`

IPython/core/completer.py

@@ -1,3320 +1,3321 b''
 """Completion for IPython.
 
 This module started as fork of the rlcompleter module in the Python standard
 library.  The original enhancements made to rlcompleter have been sent
 upstream and were accepted as of Python 2.3,
 
 This module now support a wide variety of completion mechanism both available
 for normal classic Python code, as well as completer for IPython specific
 Syntax like magics.
 
 Latex and Unicode completion
 ============================
 
 IPython and compatible frontends not only can complete your code, but can help
 you to input a wide range of characters. In particular we allow you to insert
 a unicode character using the tab completion mechanism.
 
 Forward latex/unicode completion
 --------------------------------
 
 Forward completion allows you to easily type a unicode character using its latex
 name, or unicode long description. To do so type a backslash follow by the
 relevant name and press tab:
 
 
 Using latex completion:
 
 .. code::
 
     \\alpha<tab>
     α
 
 or using unicode completion:
 
 
 .. code::
 
     \\GREEK SMALL LETTER ALPHA<tab>
     α
 
 
 Only valid Python identifiers will complete. Combining characters (like arrow or
 dots) are also available, unlike latex they need to be put after the their
 counterpart that is to say, ``F\\\\vec<tab>`` is correct, not ``\\\\vec<tab>F``.
 
 Some browsers are known to display combining characters incorrectly.
 
 Backward latex completion
 -------------------------
 
 It is sometime challenging to know how to type a character, if you are using
 IPython, or any compatible frontend you can prepend backslash to the character
 and press :kbd:`Tab` to expand it to its latex form.
 
 .. code::
 
     \\α<tab>
     \\alpha
 
 
 Both forward and backward completions can be deactivated by setting the
 :any:`Completer.backslash_combining_completions` option to ``False``.
 
 
 Experimental
 ============
 
 Starting with IPython 6.0, this module can make use of the Jedi library to
 generate completions both using static analysis of the code, and dynamically
 inspecting multiple namespaces. Jedi is an autocompletion and static analysis
 for Python. The APIs attached to this new mechanism is unstable and will
 raise unless use in an :any:`provisionalcompleter` context manager.
 
 You will find that the following are experimental:
 
     - :any:`provisionalcompleter`
     - :any:`IPCompleter.completions`
     - :any:`Completion`
     - :any:`rectify_completions`
 
 .. note::
 
     better name for :any:`rectify_completions` ?
 
 We welcome any feedback on these new API, and we also encourage you to try this
 module in debug mode (start IPython with ``--Completer.debug=True``) in order
 to have extra logging information if :any:`jedi` is crashing, or if current
 IPython completer pending deprecations are returning results not yet handled
 by :any:`jedi`
 
 Using Jedi for tab completion allow snippets like the following to work without
 having to execute any code:
 
    >>> myvar = ['hello', 42]
    ... myvar[1].bi<tab>
 
 Tab completion will be able to infer that ``myvar[1]`` is a real number without
 executing almost any code unlike the deprecated :any:`IPCompleter.greedy`
 option.
 
 Be sure to update :any:`jedi` to the latest stable version or to try the
 current development version to get better completions.
 
 Matchers
 ========
 
 All completions routines are implemented using unified *Matchers* API.
 The matchers API is provisional and subject to change without notice.
 
 The built-in matchers include:
 
 - :any:`IPCompleter.dict_key_matcher`:  dictionary key completions,
 - :any:`IPCompleter.magic_matcher`: completions for magics,
 - :any:`IPCompleter.unicode_name_matcher`,
   :any:`IPCompleter.fwd_unicode_matcher`
   and :any:`IPCompleter.latex_name_matcher`: see `Forward latex/unicode completion`_,
 - :any:`back_unicode_name_matcher` and :any:`back_latex_name_matcher`: see `Backward latex completion`_,
 - :any:`IPCompleter.file_matcher`: paths to files and directories,
 - :any:`IPCompleter.python_func_kw_matcher` - function keywords,
 - :any:`IPCompleter.python_matches` - globals and attributes (v1 API),
 - ``IPCompleter.jedi_matcher`` - static analysis with Jedi,
 - :any:`IPCompleter.custom_completer_matcher` - pluggable completer with a default
   implementation in :any:`InteractiveShell` which uses IPython hooks system
   (`complete_command`) with string dispatch (including regular expressions).
   Differently to other matchers, ``custom_completer_matcher`` will not suppress
   Jedi results to match behaviour in earlier IPython versions.
 
 Custom matchers can be added by appending to ``IPCompleter.custom_matchers`` list.
 
 Matcher API
 -----------
 
 Simplifying some details, the ``Matcher`` interface can described as
 
 .. code-block::
 
     MatcherAPIv1 = Callable[[str], list[str]]
     MatcherAPIv2 = Callable[[CompletionContext], SimpleMatcherResult]
 
     Matcher = MatcherAPIv1 | MatcherAPIv2
 
 The ``MatcherAPIv1`` reflects the matcher API as available prior to IPython 8.6.0
 and remains supported as a simplest way for generating completions. This is also
 currently the only API supported by the IPython hooks system `complete_command`.
 
 To distinguish between matcher versions ``matcher_api_version`` attribute is used.
 More precisely, the API allows to omit ``matcher_api_version`` for v1 Matchers,
 and requires a literal ``2`` for v2 Matchers.
 
 Once the API stabilises future versions may relax the requirement for specifying
 ``matcher_api_version`` by switching to :any:`functools.singledispatch`, therefore
 please do not rely on the presence of ``matcher_api_version`` for any purposes.
 
 Suppression of competing matchers
 ---------------------------------
 
 By default results from all matchers are combined, in the order determined by
 their priority. Matchers can request to suppress results from subsequent
 matchers by setting ``suppress`` to ``True`` in the ``MatcherResult``.
 
 When multiple matchers simultaneously request surpression, the results from of
 the matcher with higher priority will be returned.
 
 Sometimes it is desirable to suppress most but not all other matchers;
 this can be achieved by adding a list of identifiers of matchers which
 should not be suppressed to ``MatcherResult`` under ``do_not_suppress`` key.
 
 The suppression behaviour can is user-configurable via
 :any:`IPCompleter.suppress_competing_matchers`.
 """
 
 
 # Copyright (c) IPython Development Team.
 # Distributed under the terms of the Modified BSD License.
 #
 # Some of this code originated from rlcompleter in the Python standard library
 # Copyright (C) 2001 Python Software Foundation, www.python.org
 
 from __future__ import annotations
 import builtins as builtin_mod
 import enum
 import glob
 import inspect
 import itertools
 import keyword
 import os
 import re
 import string
 import sys
 import tokenize
 import time
 import unicodedata
 import uuid
 import warnings
 from ast import literal_eval
 from collections import defaultdict
 from contextlib import contextmanager
 from dataclasses import dataclass
 from functools import cached_property, partial
 from types import SimpleNamespace
 from typing import (
     Iterable,
     Iterator,
     List,
     Tuple,
     Union,
     Any,
     Sequence,
     Dict,
     Optional,
     TYPE_CHECKING,
     Set,
     Sized,
     TypeVar,
     Literal,
 )
 
 from IPython.core.guarded_eval import guarded_eval, EvaluationContext
 from IPython.core.error import TryNext
 from IPython.core.inputtransformer2 import ESC_MAGIC
 from IPython.core.latex_symbols import latex_symbols, reverse_latex_symbol
 from IPython.core.oinspect import InspectColors
 from IPython.testing.skipdoctest import skip_doctest
 from IPython.utils import generics
 from IPython.utils.decorators import sphinx_options
 from IPython.utils.dir2 import dir2, get_real_method
 from IPython.utils.docs import GENERATING_DOCUMENTATION
 from IPython.utils.path import ensure_dir_exists
 from IPython.utils.process import arg_split
 from traitlets import (
     Bool,
     Enum,
     Int,
     List as ListTrait,
     Unicode,
     Dict as DictTrait,
     Union as UnionTrait,
     observe,
 )
 from traitlets.config.configurable import Configurable
 
 import __main__
 
 # skip module docstests
 __skip_doctest__ = True
 
 
 try:
     import jedi
     jedi.settings.case_insensitive_completion = False
     import jedi.api.helpers
     import jedi.api.classes
     JEDI_INSTALLED = True
 except ImportError:
     JEDI_INSTALLED = False
 
 
 if TYPE_CHECKING or GENERATING_DOCUMENTATION:
     from typing import cast
     from typing_extensions import TypedDict, NotRequired, Protocol, TypeAlias, TypeGuard
 else:
     from typing import Generic
 
     def cast(type_, obj):
         """Workaround for `TypeError: MatcherAPIv2() takes no arguments`"""
         return obj
 
     # do not require on runtime
     NotRequired = Tuple  # requires Python >=3.11
     TypedDict = Dict  # by extension of `NotRequired` requires 3.11 too
     Protocol = object  # requires Python >=3.8
     TypeAlias = Any  # requires Python >=3.10
     TypeGuard = Generic  # requires Python >=3.10
 if GENERATING_DOCUMENTATION:
     from typing import TypedDict
 
 # -----------------------------------------------------------------------------
 # Globals
 #-----------------------------------------------------------------------------
 
 # ranges where we have most of the valid unicode names. We could be more finer
 # grained but is it worth it for performance  While unicode have character in the
 # range 0, 0x110000, we seem to have name for about 10% of those. (131808 as I
 # write this). With below range we cover them all, with a density of ~67%
 # biggest next gap we consider only adds up about 1% density and there are 600
 # gaps that would need hard coding.
 _UNICODE_RANGES = [(32, 0x3134b), (0xe0001, 0xe01f0)]
 
 # Public API
 __all__ = ["Completer", "IPCompleter"]
 
 if sys.platform == 'win32':
     PROTECTABLES = ' '
 else:
     PROTECTABLES = ' ()[]{}?=\\|;:\'#*"^&'
 
 # Protect against returning an enormous number of completions which the frontend
 # may have trouble processing.
 MATCHES_LIMIT = 500
 
 # Completion type reported when no type can be inferred.
 _UNKNOWN_TYPE = "<unknown>"
 
 # sentinel value to signal lack of a match
 not_found = object()
 
 class ProvisionalCompleterWarning(FutureWarning):
     """
     Exception raise by an experimental feature in this module.
 
     Wrap code in :any:`provisionalcompleter` context manager if you
     are certain you want to use an unstable feature.
     """
     pass
 
 warnings.filterwarnings('error', category=ProvisionalCompleterWarning)
 
 
 @skip_doctest
 @contextmanager
 def provisionalcompleter(action='ignore'):
     """
     This context manager has to be used in any place where unstable completer
     behavior and API may be called.
 
     >>> with provisionalcompleter():
     ...     completer.do_experimental_things() # works
 
     >>> completer.do_experimental_things() # raises.
 
     .. note::
 
         Unstable
 
         By using this context manager you agree that the API in use may change
         without warning, and that you won't complain if they do so.
 
         You also understand that, if the API is not to your liking, you should report
         a bug to explain your use case upstream.
 
         We'll be happy to get your feedback, feature requests, and improvements on
         any of the unstable APIs!
     """
     with warnings.catch_warnings():
         warnings.filterwarnings(action, category=ProvisionalCompleterWarning)
         yield
 
 
 def has_open_quotes(s):
     """Return whether a string has open quotes.
 
     This simply counts whether the number of quote characters of either type in
     the string is odd.
 
     Returns
     -------
     If there is an open quote, the quote character is returned.  Else, return
     False.
     """
     # We check " first, then ', so complex cases with nested quotes will get
     # the " to take precedence.
     if s.count('"') % 2:
         return '"'
     elif s.count("'") % 2:
         return "'"
     else:
         return False
 
 
 def protect_filename(s, protectables=PROTECTABLES):
     """Escape a string to protect certain characters."""
     if set(s) & set(protectables):
         if sys.platform == "win32":
             return '"' + s + '"'
         else:
             return "".join(("\\" + c if c in protectables else c) for c in s)
     else:
         return s
 
 
 def expand_user(path:str) -> Tuple[str, bool, str]:
     """Expand ``~``-style usernames in strings.
 
     This is similar to :func:`os.path.expanduser`, but it computes and returns
     extra information that will be useful if the input was being used in
     computing completions, and you wish to return the completions with the
     original '~' instead of its expanded value.
 
     Parameters
     ----------
     path : str
         String to be expanded.  If no ~ is present, the output is the same as the
         input.
 
     Returns
     -------
     newpath : str
         Result of ~ expansion in the input path.
     tilde_expand : bool
         Whether any expansion was performed or not.
     tilde_val : str
         The value that ~ was replaced with.
     """
     # Default values
     tilde_expand = False
     tilde_val = ''
     newpath = path
 
     if path.startswith('~'):
         tilde_expand = True
         rest = len(path)-1
         newpath = os.path.expanduser(path)
         if rest:
             tilde_val = newpath[:-rest]
         else:
             tilde_val = newpath
 
     return newpath, tilde_expand, tilde_val
 
 
 def compress_user(path:str, tilde_expand:bool, tilde_val:str) -> str:
     """Does the opposite of expand_user, with its outputs.
     """
     if tilde_expand:
         return path.replace(tilde_val, '~')
     else:
         return path
 
 
 def completions_sorting_key(word):
     """key for sorting completions
 
     This does several things:
 
     - Demote any completions starting with underscores to the end
     - Insert any %magic and %%cellmagic completions in the alphabetical order
       by their name
     """
     prio1, prio2 = 0, 0
 
     if word.startswith('__'):
         prio1 = 2
     elif word.startswith('_'):
         prio1 = 1
 
     if word.endswith('='):
         prio1 = -1
 
     if word.startswith('%%'):
         # If there's another % in there, this is something else, so leave it alone
         if not "%" in word[2:]:
             word = word[2:]
             prio2 = 2
     elif word.startswith('%'):
         if not "%" in word[1:]:
             word = word[1:]
             prio2 = 1
 
     return prio1, word, prio2
 
 
 class _FakeJediCompletion:
     """
     This is a workaround to communicate to the UI that Jedi has crashed and to
     report a bug. Will be used only id :any:`IPCompleter.debug` is set to true.
 
     Added in IPython 6.0 so should likely be removed for 7.0
 
     """
 
     def __init__(self, name):
 
         self.name = name
         self.complete = name
         self.type = 'crashed'
         self.name_with_symbols = name
         self.signature = ""
         self._origin = "fake"
         self.text = "crashed"
 
     def __repr__(self):
         return '<Fake completion object jedi has crashed>'
 
 
 _JediCompletionLike = Union[jedi.api.Completion, _FakeJediCompletion]
 
 
 class Completion:
     """
     Completion object used and returned by IPython completers.
 
     .. warning::
 
         Unstable
 
         This function is unstable, API may change without warning.
         It will also raise unless use in proper context manager.
 
     This act as a middle ground :any:`Completion` object between the
     :any:`jedi.api.classes.Completion` object and the Prompt Toolkit completion
     object. While Jedi need a lot of information about evaluator and how the
     code should be ran/inspected, PromptToolkit (and other frontend) mostly
     need user facing information.
 
     - Which range should be replaced replaced by what.
     - Some metadata (like completion type), or meta information to displayed to
       the use user.
 
     For debugging purpose we can also store the origin of the completion (``jedi``,
     ``IPython.python_matches``, ``IPython.magics_matches``...).
     """
 
     __slots__ = ['start', 'end', 'text', 'type', 'signature', '_origin']
 
     def __init__(
         self,
         start: int,
         end: int,
         text: str,
         *,
         type: Optional[str] = None,
         _origin="",
         signature="",
     ) -> None:
         warnings.warn(
             "``Completion`` is a provisional API (as of IPython 6.0). "
             "It may change without warnings. "
             "Use in corresponding context manager.",
             category=ProvisionalCompleterWarning,
             stacklevel=2,
         )
 
         self.start = start
         self.end = end
         self.text = text
         self.type = type
         self.signature = signature
         self._origin = _origin
 
     def __repr__(self):
         return '<Completion start=%s end=%s text=%r type=%r, signature=%r,>' % \
                 (self.start, self.end, self.text, self.type or '?', self.signature or '?')
 
     def __eq__(self, other) -> bool:
         """
         Equality and hash do not hash the type (as some completer may not be
         able to infer the type), but are use to (partially) de-duplicate
         completion.
 
         Completely de-duplicating completion is a bit tricker that just
         comparing as it depends on surrounding text, which Completions are not
         aware of.
         """
         return self.start == other.start and \
             self.end == other.end and \
             self.text == other.text
 
     def __hash__(self):
         return hash((self.start, self.end, self.text))
 
 
 class SimpleCompletion:
     """Completion item to be included in the dictionary returned by new-style Matcher (API v2).
 
     .. warning::
 
         Provisional
 
         This class is used to describe the currently supported attributes of
         simple completion items, and any additional implementation details
         should not be relied on. Additional attributes may be included in
         future versions, and meaning of text disambiguated from the current
         dual meaning of "text to insert" and "text to used as a label".
     """
 
     __slots__ = ["text", "type"]
 
     def __init__(self, text: str, *, type: Optional[str] = None):
         self.text = text
         self.type = type
 
     def __repr__(self):
         return f"<SimpleCompletion text={self.text!r} type={self.type!r}>"
 
 
 class _MatcherResultBase(TypedDict):
     """Definition of dictionary to be returned by new-style Matcher (API v2)."""
 
     #: Suffix of the provided ``CompletionContext.token``, if not given defaults to full token.
     matched_fragment: NotRequired[str]
 
     #: Whether to suppress results from all other matchers (True), some
     #: matchers (set of identifiers) or none (False); default is False.
     suppress: NotRequired[Union[bool, Set[str]]]
 
     #: Identifiers of matchers which should NOT be suppressed when this matcher
     #: requests to suppress all other matchers; defaults to an empty set.
     do_not_suppress: NotRequired[Set[str]]
 
     #: Are completions already ordered and should be left as-is? default is False.
     ordered: NotRequired[bool]
 
 
 @sphinx_options(show_inherited_members=True, exclude_inherited_from=["dict"])
 class SimpleMatcherResult(_MatcherResultBase, TypedDict):
     """Result of new-style completion matcher."""
 
     # note: TypedDict is added again to the inheritance chain
     # in order to get __orig_bases__ for documentation
 
     #: List of candidate completions
     completions: Sequence[SimpleCompletion] | Iterator[SimpleCompletion]
 
 
 class _JediMatcherResult(_MatcherResultBase):
     """Matching result returned by Jedi (will be processed differently)"""
 
     #: list of candidate completions
     completions: Iterator[_JediCompletionLike]
 
 
 AnyMatcherCompletion = Union[_JediCompletionLike, SimpleCompletion]
 AnyCompletion = TypeVar("AnyCompletion", AnyMatcherCompletion, Completion)
 
 
 @dataclass
 class CompletionContext:
     """Completion context provided as an argument to matchers in the Matcher API v2."""
 
     # rationale: many legacy matchers relied on completer state (`self.text_until_cursor`)
     # which was not explicitly visible as an argument of the matcher, making any refactor
     # prone to errors; by explicitly passing `cursor_position` we can decouple the matchers
     # from the completer, and make substituting them in sub-classes easier.
 
     #: Relevant fragment of code directly preceding the cursor.
     #: The extraction of token is implemented via splitter heuristic
     #: (following readline behaviour for legacy reasons), which is user configurable
     #: (by switching the greedy mode).
     token: str
 
     #: The full available content of the editor or buffer
     full_text: str
 
     #: Cursor position in the line (the same for ``full_text`` and ``text``).
     cursor_position: int
 
     #: Cursor line in ``full_text``.
     cursor_line: int
 
     #: The maximum number of completions that will be used downstream.
     #: Matchers can use this information to abort early.
     #: The built-in Jedi matcher is currently excepted from this limit.
     # If not given, return all possible completions.
     limit: Optional[int]
 
     @cached_property
     def text_until_cursor(self) -> str:
         return self.line_with_cursor[: self.cursor_position]
 
     @cached_property
     def line_with_cursor(self) -> str:
         return self.full_text.split("\n")[self.cursor_line]
 
 
 #: Matcher results for API v2.
 MatcherResult = Union[SimpleMatcherResult, _JediMatcherResult]
 
 
 class _MatcherAPIv1Base(Protocol):
     def __call__(self, text: str) -> List[str]:
         """Call signature."""
         ...
 
     #: Used to construct the default matcher identifier
     __qualname__: str
 
 
 class _MatcherAPIv1Total(_MatcherAPIv1Base, Protocol):
     #: API version
     matcher_api_version: Optional[Literal[1]]
 
     def __call__(self, text: str) -> List[str]:
         """Call signature."""
         ...
 
 
 #: Protocol describing Matcher API v1.
 MatcherAPIv1: TypeAlias = Union[_MatcherAPIv1Base, _MatcherAPIv1Total]
 
 
 class MatcherAPIv2(Protocol):
     """Protocol describing Matcher API v2."""
 
     #: API version
     matcher_api_version: Literal[2] = 2
 
     def __call__(self, context: CompletionContext) -> MatcherResult:
         """Call signature."""
         ...
 
     #: Used to construct the default matcher identifier
     __qualname__: str
 
 
 Matcher: TypeAlias = Union[MatcherAPIv1, MatcherAPIv2]
 
 
 def _is_matcher_v1(matcher: Matcher) -> TypeGuard[MatcherAPIv1]:
     api_version = _get_matcher_api_version(matcher)
     return api_version == 1
 
 
 def _is_matcher_v2(matcher: Matcher) -> TypeGuard[MatcherAPIv2]:
     api_version = _get_matcher_api_version(matcher)
     return api_version == 2
 
 
 def _is_sizable(value: Any) -> TypeGuard[Sized]:
     """Determines whether objects is sizable"""
     return hasattr(value, "__len__")
 
 
 def _is_iterator(value: Any) -> TypeGuard[Iterator]:
     """Determines whether objects is sizable"""
     return hasattr(value, "__next__")
 
 
 def has_any_completions(result: MatcherResult) -> bool:
     """Check if any result includes any completions."""
     completions = result["completions"]
     if _is_sizable(completions):
         return len(completions) != 0
     if _is_iterator(completions):
         try:
             old_iterator = completions
             first = next(old_iterator)
             result["completions"] = cast(
                 Iterator[SimpleCompletion],
                 itertools.chain([first], old_iterator),
             )
             return True
         except StopIteration:
             return False
     raise ValueError(
         "Completions returned by matcher need to be an Iterator or a Sizable"
     )
 
 
 def completion_matcher(
     *,
     priority: Optional[float] = None,
     identifier: Optional[str] = None,
     api_version: int = 1,
 ):
     """Adds attributes describing the matcher.
 
     Parameters
     ----------
     priority : Optional[float]
         The priority of the matcher, determines the order of execution of matchers.
         Higher priority means that the matcher will be executed first. Defaults to 0.
     identifier : Optional[str]
         identifier of the matcher allowing users to modify the behaviour via traitlets,
         and also used to for debugging (will be passed as ``origin`` with the completions).
 
         Defaults to matcher function's ``__qualname__`` (for example,
         ``IPCompleter.file_matcher`` for the built-in matched defined
         as a ``file_matcher`` method of the ``IPCompleter`` class).
     api_version: Optional[int]
         version of the Matcher API used by this matcher.
         Currently supported values are 1 and 2.
         Defaults to 1.
     """
 
     def wrapper(func: Matcher):
         func.matcher_priority = priority or 0  # type: ignore
         func.matcher_identifier = identifier or func.__qualname__  # type: ignore
         func.matcher_api_version = api_version  # type: ignore
         if TYPE_CHECKING:
             if api_version == 1:
                 func = cast(MatcherAPIv1, func)
             elif api_version == 2:
                 func = cast(MatcherAPIv2, func)
         return func
 
     return wrapper
 
 
 def _get_matcher_priority(matcher: Matcher):
     return getattr(matcher, "matcher_priority", 0)
 
 
 def _get_matcher_id(matcher: Matcher):
     return getattr(matcher, "matcher_identifier", matcher.__qualname__)
 
 
 def _get_matcher_api_version(matcher):
     return getattr(matcher, "matcher_api_version", 1)
 
 
 context_matcher = partial(completion_matcher, api_version=2)
 
 
 _IC = Iterable[Completion]
 
 
 def _deduplicate_completions(text: str, completions: _IC)-> _IC:
     """
     Deduplicate a set of completions.
 
     .. warning::
 
         Unstable
 
         This function is unstable, API may change without warning.
 
     Parameters
     ----------
     text : str
         text that should be completed.
     completions : Iterator[Completion]
         iterator over the completions to deduplicate
 
     Yields
     ------
     `Completions` objects
     Completions coming from multiple sources, may be different but end up having
     the same effect when applied to ``text``. If this is the case, this will
     consider completions as equal and only emit the first encountered.
     Not folded in `completions()` yet for debugging purpose, and to detect when
     the IPython completer does return things that Jedi does not, but should be
     at some point.
     """
     completions = list(completions)
     if not completions:
         return
 
     new_start = min(c.start for c in completions)
     new_end = max(c.end for c in completions)
 
     seen = set()
     for c in completions:
         new_text = text[new_start:c.start] + c.text + text[c.end:new_end]
         if new_text not in seen:
             yield c
             seen.add(new_text)
 
 
 def rectify_completions(text: str, completions: _IC, *, _debug: bool = False) -> _IC:
     """
     Rectify a set of completions to all have the same ``start`` and ``end``
 
     .. warning::
 
         Unstable
 
         This function is unstable, API may change without warning.
         It will also raise unless use in proper context manager.
 
     Parameters
     ----------
     text : str
         text that should be completed.
     completions : Iterator[Completion]
         iterator over the completions to rectify
     _debug : bool
         Log failed completion
 
     Notes
     -----
     :any:`jedi.api.classes.Completion` s returned by Jedi may not have the same start and end, though
     the Jupyter Protocol requires them to behave like so. This will readjust
     the completion to have the same ``start`` and ``end`` by padding both
     extremities with surrounding text.
 
     During stabilisation should support a ``_debug`` option to log which
     completion are return by the IPython completer and not found in Jedi in
     order to make upstream bug report.
     """
     warnings.warn("`rectify_completions` is a provisional API (as of IPython 6.0). "
                  "It may change without warnings. "
                  "Use in corresponding context manager.",
                   category=ProvisionalCompleterWarning, stacklevel=2)
 
     completions = list(completions)
     if not completions:
         return
     starts = (c.start for c in completions)
     ends = (c.end for c in completions)
 
     new_start = min(starts)
     new_end = max(ends)
 
     seen_jedi = set()
     seen_python_matches = set()
     for c in completions:
         new_text = text[new_start:c.start] + c.text + text[c.end:new_end]
         if c._origin == 'jedi':
             seen_jedi.add(new_text)
         elif c._origin == 'IPCompleter.python_matches':
             seen_python_matches.add(new_text)
         yield Completion(new_start, new_end, new_text, type=c.type, _origin=c._origin, signature=c.signature)
     diff = seen_python_matches.difference(seen_jedi)
     if diff and _debug:
         print('IPython.python matches have extras:', diff)
 
 
 if sys.platform == 'win32':
     DELIMS = ' \t\n`!@#$^&*()=+[{]}|;\'",<>?'
 else:
     DELIMS = ' \t\n`!@#$^&*()=+[{]}\\|;:\'",<>?'
 
 GREEDY_DELIMS = ' =\r\n'
 
 
 class CompletionSplitter(object):
     """An object to split an input line in a manner similar to readline.
 
     By having our own implementation, we can expose readline-like completion in
     a uniform manner to all frontends.  This object only needs to be given the
     line of text to be split and the cursor position on said line, and it
     returns the 'word' to be completed on at the cursor after splitting the
     entire line.
 
     What characters are used as splitting delimiters can be controlled by
     setting the ``delims`` attribute (this is a property that internally
     automatically builds the necessary regular expression)"""
 
     # Private interface
 
     # A string of delimiter characters.  The default value makes sense for
     # IPython's most typical usage patterns.
     _delims = DELIMS
 
     # The expression (a normal string) to be compiled into a regular expression
     # for actual splitting.  We store it as an attribute mostly for ease of
     # debugging, since this type of code can be so tricky to debug.
     _delim_expr = None
 
     # The regular expression that does the actual splitting
     _delim_re = None
 
     def __init__(self, delims=None):
         delims = CompletionSplitter._delims if delims is None else delims
         self.delims = delims
 
     @property
     def delims(self):
         """Return the string of delimiter characters."""
         return self._delims
 
     @delims.setter
     def delims(self, delims):
         """Set the delimiters for line splitting."""
         expr = '[' + ''.join('\\'+ c for c in delims) + ']'
         self._delim_re = re.compile(expr)
         self._delims = delims
         self._delim_expr = expr
 
     def split_line(self, line, cursor_pos=None):
         """Split a line of text with a cursor at the given position.
         """
         l = line if cursor_pos is None else line[:cursor_pos]
         return self._delim_re.split(l)[-1]
 
 
 
 class Completer(Configurable):
 
     greedy = Bool(
         False,
         help="""Activate greedy completion.
 
         .. deprecated:: 8.8
             Use :any:`Completer.evaluation` and :any:`Completer.auto_close_dict_keys` instead.
 
         When enabled in IPython 8.8 or newer, changes configuration as follows:
 
         - ``Completer.evaluation = 'unsafe'``
         - ``Completer.auto_close_dict_keys = True``
         """,
     ).tag(config=True)
 
     evaluation = Enum(
         ("forbidden", "minimal", "limited", "unsafe", "dangerous"),
         default_value="limited",
         help="""Policy for code evaluation under completion.
 
         Successive options allow to enable more eager evaluation for better
         completion suggestions, including for nested dictionaries, nested lists,
         or even results of function calls.
         Setting ``unsafe`` or higher can lead to evaluation of arbitrary user
         code on :kbd:`Tab` with potentially unwanted or dangerous side effects.
 
         Allowed values are:
 
         - ``forbidden``: no evaluation of code is permitted,
         - ``minimal``: evaluation of literals and access to built-in namespace;
-          no item/attribute evaluation nor access to locals/globals,
+          no item/attribute evaluationm no access to locals/globals,
+          no evaluation of any operations or comparisons.
         - ``limited``: access to all namespaces, evaluation of hard-coded methods
           (for example: :any:`dict.keys`, :any:`object.__getattr__`,
           :any:`object.__getitem__`) on allow-listed objects (for example:
           :any:`dict`, :any:`list`, :any:`tuple`, ``pandas.Series``),
         - ``unsafe``: evaluation of all methods and function calls but not of
           syntax with side-effects like `del x`,
         - ``dangerous``: completely arbitrary evaluation.
         """,
     ).tag(config=True)
 
     use_jedi = Bool(default_value=JEDI_INSTALLED,
                     help="Experimental: Use Jedi to generate autocompletions. "
                     "Default to True if jedi is installed.").tag(config=True)
 
     jedi_compute_type_timeout = Int(default_value=400,
         help="""Experimental: restrict time (in milliseconds) during which Jedi can compute types.
         Set to 0 to stop computing types. Non-zero value lower than 100ms may hurt
         performance by preventing jedi to build its cache.
         """).tag(config=True)
 
     debug = Bool(default_value=False,
                  help='Enable debug for the Completer. Mostly print extra '
                       'information for experimental jedi integration.')\
                       .tag(config=True)
 
     backslash_combining_completions = Bool(True,
         help="Enable unicode completions, e.g. \\alpha<tab> . "
              "Includes completion of latex commands, unicode names, and expanding "
              "unicode characters back to latex commands.").tag(config=True)
 
     auto_close_dict_keys = Bool(
         False,
         help="""
         Enable auto-closing dictionary keys.
 
         When enabled string keys will be suffixed with a final quote
         (matching the opening quote), tuple keys will also receive a
         separating comma if needed, and keys which are final will
         receive a closing bracket (``]``).
         """,
     ).tag(config=True)
 
     def __init__(self, namespace=None, global_namespace=None, **kwargs):
         """Create a new completer for the command line.
 
         Completer(namespace=ns, global_namespace=ns2) -> completer instance.
 
         If unspecified, the default namespace where completions are performed
         is __main__ (technically, __main__.__dict__). Namespaces should be
         given as dictionaries.
 
         An optional second namespace can be given.  This allows the completer
         to handle cases where both the local and global scopes need to be
         distinguished.
         """
 
         # Don't bind to namespace quite yet, but flag whether the user wants a
         # specific namespace or to use __main__.__dict__. This will allow us
         # to bind to __main__.__dict__ at completion time, not now.
         if namespace is None:
             self.use_main_ns = True
         else:
             self.use_main_ns = False
             self.namespace = namespace
 
         # The global namespace, if given, can be bound directly
         if global_namespace is None:
             self.global_namespace = {}
         else:
             self.global_namespace = global_namespace
 
         self.custom_matchers = []
 
         super(Completer, self).__init__(**kwargs)
 
     def complete(self, text, state):
         """Return the next possible completion for 'text'.
 
         This is called successively with state == 0, 1, 2, ... until it
         returns None.  The completion should begin with 'text'.
 
         """
         if self.use_main_ns:
             self.namespace = __main__.__dict__
 
         if state == 0:
             if "." in text:
                 self.matches = self.attr_matches(text)
             else:
                 self.matches = self.global_matches(text)
         try:
             return self.matches[state]
         except IndexError:
             return None
 
     def global_matches(self, text):
         """Compute matches when text is a simple name.
 
         Return a list of all keywords, built-in functions and names currently
         defined in self.namespace or self.global_namespace that match.
 
         """
         matches = []
         match_append = matches.append
         n = len(text)
         for lst in [
             keyword.kwlist,
             builtin_mod.__dict__.keys(),
             list(self.namespace.keys()),
             list(self.global_namespace.keys()),
         ]:
             for word in lst:
                 if word[:n] == text and word != "__builtins__":
                     match_append(word)
 
         snake_case_re = re.compile(r"[^_]+(_[^_]+)+?\Z")
         for lst in [list(self.namespace.keys()), list(self.global_namespace.keys())]:
             shortened = {
                 "_".join([sub[0] for sub in word.split("_")]): word
                 for word in lst
                 if snake_case_re.match(word)
             }
             for word in shortened.keys():
                 if word[:n] == text and word != "__builtins__":
                     match_append(shortened[word])
         return matches
 
     def attr_matches(self, text):
         """Compute matches when text contains a dot.
 
         Assuming the text is of the form NAME.NAME....[NAME], and is
         evaluatable in self.namespace or self.global_namespace, it will be
         evaluated and its attributes (as revealed by dir()) are used as
         possible completions.  (For class instances, class members are
         also considered.)
 
         WARNING: this can still invoke arbitrary C code, if an object
         with a __getattr__ hook is evaluated.
 
         """
         m2 = re.match(r"(.+)\.(\w*)$", self.line_buffer)
         if not m2:
             return []
         expr, attr = m2.group(1, 2)
 
         obj = self._evaluate_expr(expr)
 
         if obj is not_found:
             return []
 
         if self.limit_to__all__ and hasattr(obj, '__all__'):
             words = get__all__entries(obj)
         else:
             words = dir2(obj)
 
         try:
             words = generics.complete_object(obj, words)
         except TryNext:
             pass
         except AssertionError:
             raise
         except Exception:
             # Silence errors from completion function
             #raise # dbg
             pass
         # Build match list to return
         n = len(attr)
         return ["%s.%s" % (expr, w) for w in words if w[:n] == attr]
 
     def _evaluate_expr(self, expr):
         obj = not_found
         done = False
         while not done and expr:
             try:
                 obj = guarded_eval(
                     expr,
                     EvaluationContext(
                         globals=self.global_namespace,
                         locals=self.namespace,
                         evaluation=self.evaluation,
                     ),
                 )
                 done = True
             except Exception as e:
                 if self.debug:
                     print("Evaluation exception", e)
                 # trim the expression to remove any invalid prefix
                 # e.g. user starts `(d[`, so we get `expr = '(d'`,
                 # where parenthesis is not closed.
                 # TODO: make this faster by reusing parts of the computation?
                 expr = expr[1:]
         return obj
 
 def get__all__entries(obj):
     """returns the strings in the __all__ attribute"""
     try:
         words = getattr(obj, '__all__')
     except:
         return []
 
     return [w for w in words if isinstance(w, str)]
 
 
 class _DictKeyState(enum.Flag):
     """Represent state of the key match in context of other possible matches.
 
     - given `d1 = {'a': 1}` completion on `d1['<tab>` will yield `{'a': END_OF_ITEM}` as there is no tuple.
     - given `d2 = {('a', 'b'): 1}`: `d2['a', '<tab>` will yield `{'b': END_OF_TUPLE}` as there is no tuple members to add beyond `'b'`.
     - given `d3 = {('a', 'b'): 1}`: `d3['<tab>` will yield `{'a': IN_TUPLE}` as `'a'` can be added.
     - given `d4 = {'a': 1, ('a', 'b'): 2}`: `d4['<tab>` will yield `{'a': END_OF_ITEM & END_OF_TUPLE}`
     """
 
     BASELINE = 0
     END_OF_ITEM = enum.auto()
     END_OF_TUPLE = enum.auto()
     IN_TUPLE = enum.auto()
 
 
 def _parse_tokens(c):
     """Parse tokens even if there is an error."""
     tokens = []
     token_generator = tokenize.generate_tokens(iter(c.splitlines()).__next__)
     while True:
         try:
             tokens.append(next(token_generator))
         except tokenize.TokenError:
             return tokens
         except StopIteration:
             return tokens
 
 
 def _match_number_in_dict_key_prefix(prefix: str) -> Union[str, None]:
     """Match any valid Python numeric literal in a prefix of dictionary keys.
 
     References:
     - https://docs.python.org/3/reference/lexical_analysis.html#numeric-literals
     - https://docs.python.org/3/library/tokenize.html
     """
     if prefix[-1].isspace():
         # if user typed a space we do not have anything to complete
         # even if there was a valid number token before
         return None
     tokens = _parse_tokens(prefix)
     rev_tokens = reversed(tokens)
     skip_over = {tokenize.ENDMARKER, tokenize.NEWLINE}
     number = None
     for token in rev_tokens:
         if token.type in skip_over:
             continue
         if number is None:
             if token.type == tokenize.NUMBER:
                 number = token.string
                 continue
             else:
                 # we did not match a number
                 return None
         if token.type == tokenize.OP:
             if token.string == ",":
                 break
             if token.string in {"+", "-"}:
                 number = token.string + number
         else:
             return None
     return number
 
 
 _INT_FORMATS = {
     "0b": bin,
     "0o": oct,
     "0x": hex,
 }
 
 
 def match_dict_keys(
     keys: List[Union[str, bytes, Tuple[Union[str, bytes], ...]]],
     prefix: str,
     delims: str,
     extra_prefix: Optional[Tuple[Union[str, bytes], ...]] = None,
 ) -> Tuple[str, int, Dict[str, _DictKeyState]]:
     """Used by dict_key_matches, matching the prefix to a list of keys
 
     Parameters
     ----------
     keys
         list of keys in dictionary currently being completed.
     prefix
         Part of the text already typed by the user. E.g. `mydict[b'fo`
     delims
         String of delimiters to consider when finding the current key.
     extra_prefix : optional
         Part of the text already typed in multi-key index cases. E.g. for
         `mydict['foo', "bar", 'b`, this would be `('foo', 'bar')`.
 
     Returns
     -------
     A tuple of three elements: ``quote``, ``token_start``, ``matched``, with
     ``quote`` being the quote that need to be used to close current string.
     ``token_start`` the position where the replacement should start occurring,
     ``matches`` a dictionary of replacement/completion keys on keys and values
         indicating whether the state.
     """
     prefix_tuple = extra_prefix if extra_prefix else ()
 
     prefix_tuple_size = sum(
         [
             # for pandas, do not count slices as taking space
             not isinstance(k, slice)
             for k in prefix_tuple
         ]
     )
     text_serializable_types = (str, bytes, int, float, slice)
 
     def filter_prefix_tuple(key):
         # Reject too short keys
         if len(key) <= prefix_tuple_size:
             return False
         # Reject keys which cannot be serialised to text
         for k in key:
             if not isinstance(k, text_serializable_types):
                 return False
         # Reject keys that do not match the prefix
         for k, pt in zip(key, prefix_tuple):
             if k != pt and not isinstance(pt, slice):
                 return False
         # All checks passed!
         return True
 
     filtered_key_is_final: Dict[
         Union[str, bytes, int, float], _DictKeyState
     ] = defaultdict(lambda: _DictKeyState.BASELINE)
 
     for k in keys:
         # If at least one of the matches is not final, mark as undetermined.
         # This can happen with `d = {111: 'b', (111, 222): 'a'}` where
         # `111` appears final on first match but is not final on the second.
 
         if isinstance(k, tuple):
             if filter_prefix_tuple(k):
                 key_fragment = k[prefix_tuple_size]
                 filtered_key_is_final[key_fragment] |= (
                     _DictKeyState.END_OF_TUPLE
                     if len(k) == prefix_tuple_size + 1
                     else _DictKeyState.IN_TUPLE
                 )
         elif prefix_tuple_size > 0:
             # we are completing a tuple but this key is not a tuple,
             # so we should ignore it
             pass
         else:
             if isinstance(k, text_serializable_types):
                 filtered_key_is_final[k] |= _DictKeyState.END_OF_ITEM
 
     filtered_keys = filtered_key_is_final.keys()
 
     if not prefix:
         return "", 0, {repr(k): v for k, v in filtered_key_is_final.items()}
 
     quote_match = re.search("(?:\"|')", prefix)
     is_user_prefix_numeric = False
 
     if quote_match:
         quote = quote_match.group()
         valid_prefix = prefix + quote
         try:
             prefix_str = literal_eval(valid_prefix)
         except Exception:
             return "", 0, {}
     else:
         # If it does not look like a string, let's assume
         # we are dealing with a number or variable.
         number_match = _match_number_in_dict_key_prefix(prefix)
 
         # We do not want the key matcher to suggest variable names so we yield:
         if number_match is None:
             # The alternative would be to assume that user forgort the quote
             # and if the substring matches, suggest adding it at the start.
             return "", 0, {}
 
         prefix_str = number_match
         is_user_prefix_numeric = True
         quote = ""
 
     pattern = '[^' + ''.join('\\' + c for c in delims) + ']*$'
     token_match = re.search(pattern, prefix, re.UNICODE)
     assert token_match is not None # silence mypy
     token_start = token_match.start()
     token_prefix = token_match.group()
 
     matched: Dict[str, _DictKeyState] = {}
 
     str_key: Union[str, bytes]
 
     for key in filtered_keys:
         if isinstance(key, (int, float)):
             # User typed a number but this key is not a number.
             if not is_user_prefix_numeric:
                 continue
             str_key = str(key)
             if isinstance(key, int):
                 int_base = prefix_str[:2].lower()
                 # if user typed integer using binary/oct/hex notation:
                 if int_base in _INT_FORMATS:
                     int_format = _INT_FORMATS[int_base]
                     str_key = int_format(key)
         else:
             # User typed a string but this key is a number.
             if is_user_prefix_numeric:
                 continue
             str_key = key
         try:
             if not str_key.startswith(prefix_str):
                 continue
         except (AttributeError, TypeError, UnicodeError) as e:
             # Python 3+ TypeError on b'a'.startswith('a') or vice-versa
             continue
 
         # reformat remainder of key to begin with prefix
         rem = str_key[len(prefix_str) :]
         # force repr wrapped in '
         rem_repr = repr(rem + '"') if isinstance(rem, str) else repr(rem + b'"')
         rem_repr = rem_repr[1 + rem_repr.index("'"):-2]
         if quote == '"':
             # The entered prefix is quoted with ",
             # but the match is quoted with '.
             # A contained " hence needs escaping for comparison:
             rem_repr = rem_repr.replace('"', '\\"')
 
         # then reinsert prefix from start of token
         match = "%s%s" % (token_prefix, rem_repr)
 
         matched[match] = filtered_key_is_final[key]
     return quote, token_start, matched
 
 
 def cursor_to_position(text:str, line:int, column:int)->int:
     """
     Convert the (line,column) position of the cursor in text to an offset in a
     string.
 
     Parameters
     ----------
     text : str
         The text in which to calculate the cursor offset
     line : int
         Line of the cursor; 0-indexed
     column : int
         Column of the cursor 0-indexed
 
     Returns
     -------
     Position of the cursor in ``text``, 0-indexed.
 
     See Also
     --------
     position_to_cursor : reciprocal of this function
 
     """
     lines = text.split('\n')
     assert line <= len(lines), '{} <= {}'.format(str(line), str(len(lines)))
 
     return sum(len(l) + 1 for l in lines[:line]) + column
 
 def position_to_cursor(text:str, offset:int)->Tuple[int, int]:
     """
     Convert the position of the cursor in text (0 indexed) to a line
     number(0-indexed) and a column number (0-indexed) pair
 
     Position should be a valid position in ``text``.
 
     Parameters
     ----------
     text : str
         The text in which to calculate the cursor offset
     offset : int
         Position of the cursor in ``text``, 0-indexed.
 
     Returns
     -------
     (line, column) : (int, int)
         Line of the cursor; 0-indexed, column of the cursor 0-indexed
 
     See Also
     --------
     cursor_to_position : reciprocal of this function
 
     """
 
     assert 0 <= offset <= len(text) , "0 <= %s <= %s" % (offset , len(text))
 
     before = text[:offset]
     blines = before.split('\n')  # ! splitnes trim trailing \n
     line = before.count('\n')
     col = len(blines[-1])
     return line, col
 
 
 def _safe_isinstance(obj, module, class_name, *attrs):
     """Checks if obj is an instance of module.class_name if loaded
     """
     if module in sys.modules:
         m = sys.modules[module]
         for attr in [class_name, *attrs]:
             m = getattr(m, attr)
         return isinstance(obj, m)
 
 
 @context_matcher()
 def back_unicode_name_matcher(context: CompletionContext):
     """Match Unicode characters back to Unicode name
 
     Same as :any:`back_unicode_name_matches`, but adopted to new Matcher API.
     """
     fragment, matches = back_unicode_name_matches(context.text_until_cursor)
     return _convert_matcher_v1_result_to_v2(
         matches, type="unicode", fragment=fragment, suppress_if_matches=True
     )
 
 
 def back_unicode_name_matches(text: str) -> Tuple[str, Sequence[str]]:
     """Match Unicode characters back to Unicode name
 
     This does  ``☃`` -> ``\\snowman``
 
     Note that snowman is not a valid python3 combining character but will be expanded.
     Though it will not recombine back to the snowman character by the completion machinery.
 
     This will not either back-complete standard sequences like \\n, \\b ...
 
     .. deprecated:: 8.6
         You can use :meth:`back_unicode_name_matcher` instead.
 
     Returns
     =======
 
     Return a tuple with two elements:
 
     - The Unicode character that was matched (preceded with a backslash), or
         empty string,
     - a sequence (of 1), name for the match Unicode character, preceded by
         backslash, or empty if no match.
     """
     if len(text)<2:
         return '', ()
     maybe_slash = text[-2]
     if maybe_slash != '\\':
         return '', ()
 
     char = text[-1]
     # no expand on quote for completion in strings.
     # nor backcomplete standard ascii keys
     if char in string.ascii_letters or char in ('"',"'"):
         return '', ()
     try :
         unic = unicodedata.name(char)
         return '\\'+char,('\\'+unic,)
     except KeyError:
         pass
     return '', ()
 
 
 @context_matcher()
 def back_latex_name_matcher(context: CompletionContext):
     """Match latex characters back to unicode name
 
     Same as :any:`back_latex_name_matches`, but adopted to new Matcher API.
     """
     fragment, matches = back_latex_name_matches(context.text_until_cursor)
     return _convert_matcher_v1_result_to_v2(
         matches, type="latex", fragment=fragment, suppress_if_matches=True
     )
 
 
 def back_latex_name_matches(text: str) -> Tuple[str, Sequence[str]]:
     """Match latex characters back to unicode name
 
     This does ``\\ℵ`` -> ``\\aleph``
 
     .. deprecated:: 8.6
         You can use :meth:`back_latex_name_matcher` instead.
     """
     if len(text)<2:
         return '', ()
     maybe_slash = text[-2]
     if maybe_slash != '\\':
         return '', ()
 
 
     char = text[-1]
     # no expand on quote for completion in strings.
     # nor backcomplete standard ascii keys
     if char in string.ascii_letters or char in ('"',"'"):
         return '', ()
     try :
         latex = reverse_latex_symbol[char]
         # '\\' replace the \ as well
         return '\\'+char,[latex]
     except KeyError:
         pass
     return '', ()
 
 
 def _formatparamchildren(parameter) -> str:
     """
     Get parameter name and value from Jedi Private API
 
     Jedi does not expose a simple way to get `param=value` from its API.
 
     Parameters
     ----------
     parameter
         Jedi's function `Param`
 
     Returns
     -------
     A string like 'a', 'b=1', '*args', '**kwargs'
 
     """
     description = parameter.description
     if not description.startswith('param '):
         raise ValueError('Jedi function parameter description have change format.'
                          'Expected "param ...", found %r".' % description)
     return description[6:]
 
 def _make_signature(completion)-> str:
     """
     Make the signature from a jedi completion
 
     Parameters
     ----------
     completion : jedi.Completion
         object does not complete a function type
 
     Returns
     -------
     a string consisting of the function signature, with the parenthesis but
     without the function name. example:
     `(a, *args, b=1, **kwargs)`
 
     """
 
     # it looks like this might work on jedi 0.17
     if hasattr(completion, 'get_signatures'):
         signatures = completion.get_signatures()
         if not signatures:
             return  '(?)'
 
         c0 = completion.get_signatures()[0]
         return '('+c0.to_string().split('(', maxsplit=1)[1]
 
     return '(%s)'% ', '.join([f for f in (_formatparamchildren(p) for signature in completion.get_signatures()
                                           for p in signature.defined_names()) if f])
 
 
 _CompleteResult = Dict[str, MatcherResult]
 
 
 DICT_MATCHER_REGEX = re.compile(
     r"""(?x)
 (  # match dict-referring - or any get item object - expression
     .+
 )
 \[   # open bracket
 \s*  # and optional whitespace
 # Capture any number of serializable objects (e.g. "a", "b", 'c')
 # and slices
 ((?:(?:
     (?: # closed string
         [uUbB]?  # string prefix (r not handled)
         (?:
             '(?:[^']|(?<!\\)\\')*'
         |
             "(?:[^"]|(?<!\\)\\")*"
         )
     )
     |
         # capture integers and slices
         (?:[-+]?\d+)?(?::(?:[-+]?\d+)?){0,2}
     |
         # integer in bin/hex/oct notation
         0[bBxXoO]_?(?:\w|\d)+
     )
     \s*,\s*
 )*)
 ((?:
     (?: # unclosed string
         [uUbB]?  # string prefix (r not handled)
         (?:
             '(?:[^']|(?<!\\)\\')*
             |
             "(?:[^"]|(?<!\\)\\")*
         )
     )
     |
         # unfinished integer
         (?:[-+]?\d+)
     |
         # integer in bin/hex/oct notation
         0[bBxXoO]_?(?:\w|\d)+
     )
 )?
 $
 """
 )
 
 
 def _convert_matcher_v1_result_to_v2(
     matches: Sequence[str],
     type: str,
     fragment: Optional[str] = None,
     suppress_if_matches: bool = False,
 ) -> SimpleMatcherResult:
     """Utility to help with transition"""
     result = {
         "completions": [SimpleCompletion(text=match, type=type) for match in matches],
         "suppress": (True if matches else False) if suppress_if_matches else False,
     }
     if fragment is not None:
         result["matched_fragment"] = fragment
     return cast(SimpleMatcherResult, result)
 
 
 class IPCompleter(Completer):
     """Extension of the completer class with IPython-specific features"""
 
     @observe('greedy')
     def _greedy_changed(self, change):
         """update the splitter and readline delims when greedy is changed"""
         if change["new"]:
             self.evaluation = "unsafe"
             self.auto_close_dict_keys = True
             self.splitter.delims = GREEDY_DELIMS
         else:
             self.evaluation = "limited"
             self.auto_close_dict_keys = False
             self.splitter.delims = DELIMS
 
     dict_keys_only = Bool(
         False,
         help="""
         Whether to show dict key matches only.
 
         (disables all matchers except for `IPCompleter.dict_key_matcher`).
         """,
     )
 
     suppress_competing_matchers = UnionTrait(
         [Bool(allow_none=True), DictTrait(Bool(None, allow_none=True))],
         default_value=None,
         help="""
         Whether to suppress completions from other *Matchers*.
 
         When set to ``None`` (default) the matchers will attempt to auto-detect
         whether suppression of other matchers is desirable. For example, at
         the beginning of a line followed by `%` we expect a magic completion
         to be the only applicable option, and after ``my_dict['`` we usually
         expect a completion with an existing dictionary key.
 
         If you want to disable this heuristic and see completions from all matchers,
         set ``IPCompleter.suppress_competing_matchers = False``.
         To disable the heuristic for specific matchers provide a dictionary mapping:
         ``IPCompleter.suppress_competing_matchers = {'IPCompleter.dict_key_matcher': False}``.
 
         Set ``IPCompleter.suppress_competing_matchers = True`` to limit
         completions to the set of matchers with the highest priority;
         this is equivalent to ``IPCompleter.merge_completions`` and
         can be beneficial for performance, but will sometimes omit relevant
         candidates from matchers further down the priority list.
         """,
     ).tag(config=True)
 
     merge_completions = Bool(
         True,
         help="""Whether to merge completion results into a single list
 
         If False, only the completion results from the first non-empty
         completer will be returned.
 
         As of version 8.6.0, setting the value to ``False`` is an alias for:
         ``IPCompleter.suppress_competing_matchers = True.``.
         """,
     ).tag(config=True)
 
     disable_matchers = ListTrait(
         Unicode(),
         help="""List of matchers to disable.
 
         The list should contain matcher identifiers (see :any:`completion_matcher`).
         """,
     ).tag(config=True)
 
     omit__names = Enum(
         (0, 1, 2),
         default_value=2,
         help="""Instruct the completer to omit private method names
 
         Specifically, when completing on ``object.<tab>``.
 
         When 2 [default]: all names that start with '_' will be excluded.
 
         When 1: all 'magic' names (``__foo__``) will be excluded.
 
         When 0: nothing will be excluded.
         """
     ).tag(config=True)
     limit_to__all__ = Bool(False,
         help="""
         DEPRECATED as of version 5.0.
 
         Instruct the completer to use __all__ for the completion
 
         Specifically, when completing on ``object.<tab>``.
 
         When True: only those names in obj.__all__ will be included.
 
         When False [default]: the __all__ attribute is ignored
         """,
     ).tag(config=True)
 
     profile_completions = Bool(
         default_value=False,
         help="If True, emit profiling data for completion subsystem using cProfile."
     ).tag(config=True)
 
     profiler_output_dir = Unicode(
         default_value=".completion_profiles",
         help="Template for path at which to output profile data for completions."
     ).tag(config=True)
 
     @observe('limit_to__all__')
     def _limit_to_all_changed(self, change):
         warnings.warn('`IPython.core.IPCompleter.limit_to__all__` configuration '
             'value has been deprecated since IPython 5.0, will be made to have '
             'no effects and then removed in future version of IPython.',
             UserWarning)
 
     def __init__(
         self, shell=None, namespace=None, global_namespace=None, config=None, **kwargs
     ):
         """IPCompleter() -> completer
 
         Return a completer object.
 
         Parameters
         ----------
         shell
             a pointer to the ipython shell itself.  This is needed
             because this completer knows about magic functions, and those can
             only be accessed via the ipython instance.
         namespace : dict, optional
             an optional dict where completions are performed.
         global_namespace : dict, optional
             secondary optional dict for completions, to
             handle cases (such as IPython embedded inside functions) where
             both Python scopes are visible.
         config : Config
             traitlet's config object
         **kwargs
             passed to super class unmodified.
         """
 
         self.magic_escape = ESC_MAGIC
         self.splitter = CompletionSplitter()
 
         # _greedy_changed() depends on splitter and readline being defined:
         super().__init__(
             namespace=namespace,
             global_namespace=global_namespace,
             config=config,
             **kwargs,
         )
 
         # List where completion matches will be stored
         self.matches = []
         self.shell = shell
         # Regexp to split filenames with spaces in them
         self.space_name_re = re.compile(r'([^\\] )')
         # Hold a local ref. to glob.glob for speed
         self.glob = glob.glob
 
         # Determine if we are running on 'dumb' terminals, like (X)Emacs
         # buffers, to avoid completion problems.
         term = os.environ.get('TERM','xterm')
         self.dumb_terminal = term in ['dumb','emacs']
 
         # Special handling of backslashes needed in win32 platforms
         if sys.platform == "win32":
             self.clean_glob = self._clean_glob_win32
         else:
             self.clean_glob = self._clean_glob
 
         #regexp to parse docstring for function signature
         self.docstring_sig_re = re.compile(r'^[\w|\s.]+\(([^)]*)\).*')
         self.docstring_kwd_re = re.compile(r'[\s|\[]*(\w+)(?:\s*=\s*.*)')
         #use this if positional argument name is also needed
         #= re.compile(r'[\s|\[]*(\w+)(?:\s*=?\s*.*)')
 
         self.magic_arg_matchers = [
             self.magic_config_matcher,
             self.magic_color_matcher,
         ]
 
         # This is set externally by InteractiveShell
         self.custom_completers = None
 
         # This is a list of names of unicode characters that can be completed
         # into their corresponding unicode value. The list is large, so we
         # lazily initialize it on first use. Consuming code should access this
         # attribute through the `@unicode_names` property.
         self._unicode_names = None
 
         self._backslash_combining_matchers = [
             self.latex_name_matcher,
             self.unicode_name_matcher,
             back_latex_name_matcher,
             back_unicode_name_matcher,
             self.fwd_unicode_matcher,
         ]
 
         if not self.backslash_combining_completions:
             for matcher in self._backslash_combining_matchers:
                 self.disable_matchers.append(_get_matcher_id(matcher))
 
         if not self.merge_completions:
             self.suppress_competing_matchers = True
 
     @property
     def matchers(self) -> List[Matcher]:
         """All active matcher routines for completion"""
         if self.dict_keys_only:
             return [self.dict_key_matcher]
 
         if self.use_jedi:
             return [
                 *self.custom_matchers,
                 *self._backslash_combining_matchers,
                 *self.magic_arg_matchers,
                 self.custom_completer_matcher,
                 self.magic_matcher,
                 self._jedi_matcher,
                 self.dict_key_matcher,
                 self.file_matcher,
             ]
         else:
             return [
                 *self.custom_matchers,
                 *self._backslash_combining_matchers,
                 *self.magic_arg_matchers,
                 self.custom_completer_matcher,
                 self.dict_key_matcher,
                 # TODO: convert python_matches to v2 API
                 self.magic_matcher,
                 self.python_matches,
                 self.file_matcher,
                 self.python_func_kw_matcher,
             ]
 
     def all_completions(self, text:str) -> List[str]:
         """
         Wrapper around the completion methods for the benefit of emacs.
         """
         prefix = text.rpartition('.')[0]
         with provisionalcompleter():
             return ['.'.join([prefix, c.text]) if prefix and self.use_jedi else c.text
                     for c in self.completions(text, len(text))]
 
         return self.complete(text)[1]
 
     def _clean_glob(self, text:str):
         return self.glob("%s*" % text)
 
     def _clean_glob_win32(self, text:str):
         return [f.replace("\\","/")
                 for f in self.glob("%s*" % text)]
 
     @context_matcher()
     def file_matcher(self, context: CompletionContext) -> SimpleMatcherResult:
         """Same as :any:`file_matches`, but adopted to new Matcher API."""
         matches = self.file_matches(context.token)
         # TODO: add a heuristic for suppressing (e.g. if it has OS-specific delimiter,
         #  starts with `/home/`, `C:\`, etc)
         return _convert_matcher_v1_result_to_v2(matches, type="path")
 
     def file_matches(self, text: str) -> List[str]:
         """Match filenames, expanding ~USER type strings.
 
         Most of the seemingly convoluted logic in this completer is an
         attempt to handle filenames with spaces in them.  And yet it's not
         quite perfect, because Python's readline doesn't expose all of the
         GNU readline details needed for this to be done correctly.
 
         For a filename with a space in it, the printed completions will be
         only the parts after what's already been typed (instead of the
         full completions, as is normally done).  I don't think with the
         current (as of Python 2.3) Python readline it's possible to do
         better.
 
         .. deprecated:: 8.6
             You can use :meth:`file_matcher` instead.
         """
 
         # chars that require escaping with backslash - i.e. chars
         # that readline treats incorrectly as delimiters, but we
         # don't want to treat as delimiters in filename matching
         # when escaped with backslash
         if text.startswith('!'):
             text = text[1:]
             text_prefix = u'!'
         else:
             text_prefix = u''
 
         text_until_cursor = self.text_until_cursor
         # track strings with open quotes
         open_quotes = has_open_quotes(text_until_cursor)
 
         if '(' in text_until_cursor or '[' in text_until_cursor:
             lsplit = text
         else:
             try:
                 # arg_split ~ shlex.split, but with unicode bugs fixed by us
                 lsplit = arg_split(text_until_cursor)[-1]
             except ValueError:
                 # typically an unmatched ", or backslash without escaped char.
                 if open_quotes:
                     lsplit = text_until_cursor.split(open_quotes)[-1]
                 else:
                     return []
             except IndexError:
                 # tab pressed on empty line
                 lsplit = ""
 
         if not open_quotes and lsplit != protect_filename(lsplit):
             # if protectables are found, do matching on the whole escaped name
             has_protectables = True
             text0,text = text,lsplit
         else:
             has_protectables = False
             text = os.path.expanduser(text)
 
         if text == "":
             return [text_prefix + protect_filename(f) for f in self.glob("*")]
 
         # Compute the matches from the filesystem
         if sys.platform == 'win32':
             m0 = self.clean_glob(text)
         else:
             m0 = self.clean_glob(text.replace('\\', ''))
 
         if has_protectables:
             # If we had protectables, we need to revert our changes to the
             # beginning of filename so that we don't double-write the part
             # of the filename we have so far
             len_lsplit = len(lsplit)
             matches = [text_prefix + text0 +
                        protect_filename(f[len_lsplit:]) for f in m0]
         else:
             if open_quotes:
                 # if we have a string with an open quote, we don't need to
                 # protect the names beyond the quote (and we _shouldn't_, as
                 # it would cause bugs when the filesystem call is made).
                 matches = m0 if sys.platform == "win32" else\
                     [protect_filename(f, open_quotes) for f in m0]
             else:
                 matches = [text_prefix +
                            protect_filename(f) for f in m0]
 
         # Mark directories in input list by appending '/' to their names.
         return [x+'/' if os.path.isdir(x) else x for x in matches]
 
     @context_matcher()
     def magic_matcher(self, context: CompletionContext) -> SimpleMatcherResult:
         """Match magics."""
         text = context.token
         matches = self.magic_matches(text)
         result = _convert_matcher_v1_result_to_v2(matches, type="magic")
         is_magic_prefix = len(text) > 0 and text[0] == "%"
         result["suppress"] = is_magic_prefix and bool(result["completions"])
         return result
 
     def magic_matches(self, text: str):
         """Match magics.
 
         .. deprecated:: 8.6
             You can use :meth:`magic_matcher` instead.
         """
         # Get all shell magics now rather than statically, so magics loaded at
         # runtime show up too.
         lsm = self.shell.magics_manager.lsmagic()
         line_magics = lsm['line']
         cell_magics = lsm['cell']
         pre = self.magic_escape
         pre2 = pre+pre
 
         explicit_magic = text.startswith(pre)
 
         # Completion logic:
         # - user gives %%: only do cell magics
         # - user gives %: do both line and cell magics
         # - no prefix: do both
         # In other words, line magics are skipped if the user gives %% explicitly
         #
         # We also exclude magics that match any currently visible names:
         # https://github.com/ipython/ipython/issues/4877, unless the user has
         # typed a %:
         # https://github.com/ipython/ipython/issues/10754
         bare_text = text.lstrip(pre)
         global_matches = self.global_matches(bare_text)
         if not explicit_magic:
             def matches(magic):
                 """
                 Filter magics, in particular remove magics that match
                 a name present in global namespace.
                 """
                 return ( magic.startswith(bare_text) and
                          magic not in global_matches )
         else:
             def matches(magic):
                 return magic.startswith(bare_text)
 
         comp = [ pre2+m for m in cell_magics if matches(m)]
         if not text.startswith(pre2):
             comp += [ pre+m for m in line_magics if matches(m)]
 
         return comp
 
     @context_matcher()
     def magic_config_matcher(self, context: CompletionContext) -> SimpleMatcherResult:
         """Match class names and attributes for %config magic."""
         # NOTE: uses `line_buffer` equivalent for compatibility
         matches = self.magic_config_matches(context.line_with_cursor)
         return _convert_matcher_v1_result_to_v2(matches, type="param")
 
     def magic_config_matches(self, text: str) -> List[str]:
         """Match class names and attributes for %config magic.
 
         .. deprecated:: 8.6
             You can use :meth:`magic_config_matcher` instead.
         """
         texts = text.strip().split()
 
         if len(texts) > 0 and (texts[0] == 'config' or texts[0] == '%config'):
             # get all configuration classes
             classes = sorted(set([ c for c in self.shell.configurables
                                    if c.__class__.class_traits(config=True)
                                    ]), key=lambda x: x.__class__.__name__)
             classnames = [ c.__class__.__name__ for c in classes ]
 
             # return all classnames if config or %config is given
             if len(texts) == 1:
                 return classnames
 
             # match classname
             classname_texts = texts[1].split('.')
             classname = classname_texts[0]
             classname_matches = [ c for c in classnames
                                   if c.startswith(classname) ]
 
             # return matched classes or the matched class with attributes
             if texts[1].find('.') < 0:
                 return classname_matches
             elif len(classname_matches) == 1 and \
                             classname_matches[0] == classname:
                 cls = classes[classnames.index(classname)].__class__
                 help = cls.class_get_help()
                 # strip leading '--' from cl-args:
                 help = re.sub(re.compile(r'^--', re.MULTILINE), '', help)
                 return [ attr.split('=')[0]
                          for attr in help.strip().splitlines()
                          if attr.startswith(texts[1]) ]
         return []
 
     @context_matcher()
     def magic_color_matcher(self, context: CompletionContext) -> SimpleMatcherResult:
         """Match color schemes for %colors magic."""
         # NOTE: uses `line_buffer` equivalent for compatibility
         matches = self.magic_color_matches(context.line_with_cursor)
         return _convert_matcher_v1_result_to_v2(matches, type="param")
 
     def magic_color_matches(self, text: str) -> List[str]:
         """Match color schemes for %colors magic.
 
         .. deprecated:: 8.6
             You can use :meth:`magic_color_matcher` instead.
         """
         texts = text.split()
         if text.endswith(' '):
             # .split() strips off the trailing whitespace. Add '' back
             # so that: '%colors ' -> ['%colors', '']
             texts.append('')
 
         if len(texts) == 2 and (texts[0] == 'colors' or texts[0] == '%colors'):
             prefix = texts[1]
             return [ color for color in InspectColors.keys()
                      if color.startswith(prefix) ]
         return []
 
     @context_matcher(identifier="IPCompleter.jedi_matcher")
     def _jedi_matcher(self, context: CompletionContext) -> _JediMatcherResult:
         matches = self._jedi_matches(
             cursor_column=context.cursor_position,
             cursor_line=context.cursor_line,
             text=context.full_text,
         )
         return {
             "completions": matches,
             # static analysis should not suppress other matchers
             "suppress": False,
         }
 
     def _jedi_matches(
         self, cursor_column: int, cursor_line: int, text: str
     ) -> Iterator[_JediCompletionLike]:
         """
         Return a list of :any:`jedi.api.Completion`s object from a ``text`` and
         cursor position.
 
         Parameters
         ----------
         cursor_column : int
             column position of the cursor in ``text``, 0-indexed.
         cursor_line : int
             line position of the cursor in ``text``, 0-indexed
         text : str
             text to complete
 
         Notes
         -----
         If ``IPCompleter.debug`` is ``True`` may return a :any:`_FakeJediCompletion`
         object containing a string with the Jedi debug information attached.
 
         .. deprecated:: 8.6
             You can use :meth:`_jedi_matcher` instead.
         """
         namespaces = [self.namespace]
         if self.global_namespace is not None:
             namespaces.append(self.global_namespace)
 
         completion_filter = lambda x:x
         offset = cursor_to_position(text, cursor_line, cursor_column)
         # filter output if we are completing for object members
         if offset:
             pre = text[offset-1]
             if pre == '.':
                 if self.omit__names == 2:
                     completion_filter = lambda c:not c.name.startswith('_')
                 elif self.omit__names == 1:
                     completion_filter = lambda c:not (c.name.startswith('__') and c.name.endswith('__'))
                 elif self.omit__names == 0:
                     completion_filter = lambda x:x
                 else:
                     raise ValueError("Don't understand self.omit__names == {}".format(self.omit__names))
 
         interpreter = jedi.Interpreter(text[:offset], namespaces)
         try_jedi = True
 
         try:
             # find the first token in the current tree -- if it is a ' or " then we are in a string
             completing_string = False
             try:
                 first_child = next(c for c in interpreter._get_module().tree_node.children if hasattr(c, 'value'))
             except StopIteration:
                 pass
             else:
                 # note the value may be ', ", or it may also be ''' or """, or
                 # in some cases, """what/you/typed..., but all of these are
                 # strings.
                 completing_string = len(first_child.value) > 0 and first_child.value[0] in {"'", '"'}
 
             # if we are in a string jedi is likely not the right candidate for
             # now. Skip it.
             try_jedi = not completing_string
         except Exception as e:
             # many of things can go wrong, we are using private API just don't crash.
             if self.debug:
                 print("Error detecting if completing a non-finished string :", e, '|')
 
         if not try_jedi:
             return iter([])
         try:
             return filter(completion_filter, interpreter.complete(column=cursor_column, line=cursor_line + 1))
         except Exception as e:
             if self.debug:
                 return iter(
                     [
                         _FakeJediCompletion(
                             'Oops Jedi has crashed, please report a bug with the following:\n"""\n%s\ns"""'
                             % (e)
                         )
                     ]
                 )
             else:
                 return iter([])
 
     @completion_matcher(api_version=1)
     def python_matches(self, text: str) -> Iterable[str]:
         """Match attributes or global python names"""
         if "." in text:
             try:
                 matches = self.attr_matches(text)
                 if text.endswith('.') and self.omit__names:
                     if self.omit__names == 1:
                         # true if txt is _not_ a __ name, false otherwise:
                         no__name = (lambda txt:
                                     re.match(r'.*\.__.*?__',txt) is None)
                     else:
                         # true if txt is _not_ a _ name, false otherwise:
                         no__name = (lambda txt:
                                     re.match(r'\._.*?',txt[txt.rindex('.'):]) is None)
                     matches = filter(no__name, matches)
             except NameError:
                 # catches <undefined attributes>.<tab>
                 matches = []
         else:
             matches = self.global_matches(text)
         return matches
 
     def _default_arguments_from_docstring(self, doc):
         """Parse the first line of docstring for call signature.
 
         Docstring should be of the form 'min(iterable[, key=func])\n'.
         It can also parse cython docstring of the form
         'Minuit.migrad(self, int ncall=10000, resume=True, int nsplit=1)'.
         """
         if doc is None:
             return []
 
         #care only the firstline
         line = doc.lstrip().splitlines()[0]
 
         #p = re.compile(r'^[\w|\s.]+\(([^)]*)\).*')
         #'min(iterable[, key=func])\n' -> 'iterable[, key=func]'
         sig = self.docstring_sig_re.search(line)
         if sig is None:
             return []
         # iterable[, key=func]' -> ['iterable[' ,' key=func]']
         sig = sig.groups()[0].split(',')
         ret = []
         for s in sig:
             #re.compile(r'[\s|\[]*(\w+)(?:\s*=\s*.*)')
             ret += self.docstring_kwd_re.findall(s)
         return ret
 
     def _default_arguments(self, obj):
         """Return the list of default arguments of obj if it is callable,
         or empty list otherwise."""
         call_obj = obj
         ret = []
         if inspect.isbuiltin(obj):
             pass
         elif not (inspect.isfunction(obj) or inspect.ismethod(obj)):
             if inspect.isclass(obj):
                 #for cython embedsignature=True the constructor docstring
                 #belongs to the object itself not __init__
                 ret += self._default_arguments_from_docstring(
                             getattr(obj, '__doc__', ''))
                 # for classes, check for __init__,__new__
                 call_obj = (getattr(obj, '__init__', None) or
                        getattr(obj, '__new__', None))
             # for all others, check if they are __call__able
             elif hasattr(obj, '__call__'):
                 call_obj = obj.__call__
         ret += self._default_arguments_from_docstring(
                  getattr(call_obj, '__doc__', ''))
 
         _keeps = (inspect.Parameter.KEYWORD_ONLY,
                   inspect.Parameter.POSITIONAL_OR_KEYWORD)
 
         try:
             sig = inspect.signature(obj)
             ret.extend(k for k, v in sig.parameters.items() if
                        v.kind in _keeps)
         except ValueError:
             pass
 
         return list(set(ret))
 
     @context_matcher()
     def python_func_kw_matcher(self, context: CompletionContext) -> SimpleMatcherResult:
         """Match named parameters (kwargs) of the last open function."""
         matches = self.python_func_kw_matches(context.token)
         return _convert_matcher_v1_result_to_v2(matches, type="param")
 
     def python_func_kw_matches(self, text):
         """Match named parameters (kwargs) of the last open function.
 
         .. deprecated:: 8.6
             You can use :meth:`python_func_kw_matcher` instead.
         """
 
         if "." in text: # a parameter cannot be dotted
             return []
         try: regexp = self.__funcParamsRegex
         except AttributeError:
             regexp = self.__funcParamsRegex = re.compile(r'''
                 '.*?(?<!\\)' |    # single quoted strings or
                 ".*?(?<!\\)" |    # double quoted strings or
                 \w+          |    # identifier
                 \S                # other characters
                 ''', re.VERBOSE | re.DOTALL)
         # 1. find the nearest identifier that comes before an unclosed
         # parenthesis before the cursor
         # e.g. for "foo (1+bar(x), pa<cursor>,a=1)", the candidate is "foo"
         tokens = regexp.findall(self.text_until_cursor)
         iterTokens = reversed(tokens); openPar = 0
 
         for token in iterTokens:
             if token == ')':
                 openPar -= 1
             elif token == '(':
                 openPar += 1
                 if openPar > 0:
                     # found the last unclosed parenthesis
                     break
         else:
             return []
         # 2. Concatenate dotted names ("foo.bar" for "foo.bar(x, pa" )
         ids = []
         isId = re.compile(r'\w+$').match
 
         while True:
             try:
                 ids.append(next(iterTokens))
                 if not isId(ids[-1]):
                     ids.pop(); break
                 if not next(iterTokens) == '.':
                     break
             except StopIteration:
                 break
 
         # Find all named arguments already assigned to, as to avoid suggesting
         # them again
         usedNamedArgs = set()
         par_level = -1
         for token, next_token in zip(tokens, tokens[1:]):
             if token == '(':
                 par_level += 1
             elif token == ')':
                 par_level -= 1
 
             if par_level != 0:
                 continue
 
             if next_token != '=':
                 continue
 
             usedNamedArgs.add(token)
 
         argMatches = []
         try:
             callableObj = '.'.join(ids[::-1])
             namedArgs = self._default_arguments(eval(callableObj,
                                                     self.namespace))
 
             # Remove used named arguments from the list, no need to show twice
             for namedArg in set(namedArgs) - usedNamedArgs:
                 if namedArg.startswith(text):
                     argMatches.append("%s=" %namedArg)
         except:
             pass
 
         return argMatches
 
     @staticmethod
     def _get_keys(obj: Any) -> List[Any]:
         # Objects can define their own completions by defining an
         # _ipy_key_completions_() method.
         method = get_real_method(obj, '_ipython_key_completions_')
         if method is not None:
             return method()
 
         # Special case some common in-memory dict-like types
         if isinstance(obj, dict) or _safe_isinstance(obj, "pandas", "DataFrame"):
             try:
                 return list(obj.keys())
             except Exception:
                 return []
         elif _safe_isinstance(obj, "pandas", "core", "indexing", "_LocIndexer"):
             try:
                 return list(obj.obj.keys())
             except Exception:
                 return []
         elif _safe_isinstance(obj, 'numpy', 'ndarray') or\
              _safe_isinstance(obj, 'numpy', 'void'):
             return obj.dtype.names or []
         return []
 
     @context_matcher()
     def dict_key_matcher(self, context: CompletionContext) -> SimpleMatcherResult:
         """Match string keys in a dictionary, after e.g. ``foo[``."""
         matches = self.dict_key_matches(context.token)
         return _convert_matcher_v1_result_to_v2(
             matches, type="dict key", suppress_if_matches=True
         )
 
     def dict_key_matches(self, text: str) -> List[str]:
         """Match string keys in a dictionary, after e.g. ``foo[``.
 
         .. deprecated:: 8.6
             You can use :meth:`dict_key_matcher` instead.
         """
 
         # Short-circuit on closed dictionary (regular expression would
         # not match anyway, but would take quite a while).
         if self.text_until_cursor.strip().endswith("]"):
             return []
 
         match = DICT_MATCHER_REGEX.search(self.text_until_cursor)
 
         if match is None:
             return []
 
         expr, prior_tuple_keys, key_prefix = match.groups()
 
         obj = self._evaluate_expr(expr)
 
         if obj is not_found:
             return []
 
         keys = self._get_keys(obj)
         if not keys:
             return keys
 
         tuple_prefix = guarded_eval(
             prior_tuple_keys,
             EvaluationContext(
                 globals=self.global_namespace,
                 locals=self.namespace,
                 evaluation=self.evaluation,
                 in_subscript=True,
             ),
         )
 
         closing_quote, token_offset, matches = match_dict_keys(
             keys, key_prefix, self.splitter.delims, extra_prefix=tuple_prefix
         )
         if not matches:
             return []
 
         # get the cursor position of
         # - the text being completed
         # - the start of the key text
         # - the start of the completion
         text_start = len(self.text_until_cursor) - len(text)
         if key_prefix:
             key_start = match.start(3)
             completion_start = key_start + token_offset
         else:
             key_start = completion_start = match.end()
 
         # grab the leading prefix, to make sure all completions start with `text`
         if text_start > key_start:
             leading = ''
         else:
             leading = text[text_start:completion_start]
 
         # append closing quote and bracket as appropriate
         # this is *not* appropriate if the opening quote or bracket is outside
         # the text given to this method, e.g. `d["""a\nt
         can_close_quote = False
         can_close_bracket = False
 
         continuation = self.line_buffer[len(self.text_until_cursor) :].strip()
 
         if continuation.startswith(closing_quote):
             # do not close if already closed, e.g. `d['a<tab>'`
             continuation = continuation[len(closing_quote) :]
         else:
             can_close_quote = True
 
         continuation = continuation.strip()
 
         # e.g. `pandas.DataFrame` has different tuple indexer behaviour,
         # handling it is out of scope, so let's avoid appending suffixes.
         has_known_tuple_handling = isinstance(obj, dict)
 
         can_close_bracket = (
             not continuation.startswith("]") and self.auto_close_dict_keys
         )
         can_close_tuple_item = (
             not continuation.startswith(",")
             and has_known_tuple_handling
             and self.auto_close_dict_keys
         )
         can_close_quote = can_close_quote and self.auto_close_dict_keys
 
         # fast path if closing qoute should be appended but not suffix is allowed
         if not can_close_quote and not can_close_bracket and closing_quote:
             return [leading + k for k in matches]
 
         results = []
 
         end_of_tuple_or_item = _DictKeyState.END_OF_TUPLE | _DictKeyState.END_OF_ITEM
 
         for k, state_flag in matches.items():
             result = leading + k
             if can_close_quote and closing_quote:
                 result += closing_quote
 
             if state_flag == end_of_tuple_or_item:
                 # We do not know which suffix to add,
                 # e.g. both tuple item and string
                 # match this item.
                 pass
 
             if state_flag in end_of_tuple_or_item and can_close_bracket:
                 result += "]"
             if state_flag == _DictKeyState.IN_TUPLE and can_close_tuple_item:
                 result += ", "
             results.append(result)
         return results
 
     @context_matcher()
     def unicode_name_matcher(self, context: CompletionContext):
         """Same as :any:`unicode_name_matches`, but adopted to new Matcher API."""
         fragment, matches = self.unicode_name_matches(context.text_until_cursor)
         return _convert_matcher_v1_result_to_v2(
             matches, type="unicode", fragment=fragment, suppress_if_matches=True
         )
 
     @staticmethod
     def unicode_name_matches(text: str) -> Tuple[str, List[str]]:
         """Match Latex-like syntax for unicode characters base
         on the name of the character.
 
         This does  ``\\GREEK SMALL LETTER ETA`` -> ``η``
 
         Works only on valid python 3 identifier, or on combining characters that
         will combine to form a valid identifier.
         """
         slashpos = text.rfind('\\')
         if slashpos > -1:
             s = text[slashpos+1:]
             try :
                 unic = unicodedata.lookup(s)
                 # allow combining chars
                 if ('a'+unic).isidentifier():
                     return '\\'+s,[unic]
             except KeyError:
                 pass
         return '', []
 
     @context_matcher()
     def latex_name_matcher(self, context: CompletionContext):
         """Match Latex syntax for unicode characters.
 
         This does both ``\\alp`` -> ``\\alpha`` and ``\\alpha`` -> ``α``
         """
         fragment, matches = self.latex_matches(context.text_until_cursor)
         return _convert_matcher_v1_result_to_v2(
             matches, type="latex", fragment=fragment, suppress_if_matches=True
         )
 
     def latex_matches(self, text: str) -> Tuple[str, Sequence[str]]:
         """Match Latex syntax for unicode characters.
 
         This does both ``\\alp`` -> ``\\alpha`` and ``\\alpha`` -> ``α``
 
         .. deprecated:: 8.6
             You can use :meth:`latex_name_matcher` instead.
         """
         slashpos = text.rfind('\\')
         if slashpos > -1:
             s = text[slashpos:]
             if s in latex_symbols:
                 # Try to complete a full latex symbol to unicode
                 # \\alpha -> α
                 return s, [latex_symbols[s]]
             else:
                 # If a user has partially typed a latex symbol, give them
                 # a full list of options \al -> [\aleph, \alpha]
                 matches = [k for k in latex_symbols if k.startswith(s)]
                 if matches:
                     return s, matches
         return '', ()
 
     @context_matcher()
     def custom_completer_matcher(self, context):
         """Dispatch custom completer.
 
         If a match is found, suppresses all other matchers except for Jedi.
         """
         matches = self.dispatch_custom_completer(context.token) or []
         result = _convert_matcher_v1_result_to_v2(
             matches, type=_UNKNOWN_TYPE, suppress_if_matches=True
         )
         result["ordered"] = True
         result["do_not_suppress"] = {_get_matcher_id(self._jedi_matcher)}
         return result
 
     def dispatch_custom_completer(self, text):
         """
         .. deprecated:: 8.6
             You can use :meth:`custom_completer_matcher` instead.
         """
         if not self.custom_completers:
             return
 
         line = self.line_buffer
         if not line.strip():
             return None
 
         # Create a little structure to pass all the relevant information about
         # the current completion to any custom completer.
         event = SimpleNamespace()
         event.line = line
         event.symbol = text
         cmd = line.split(None,1)[0]
         event.command = cmd
         event.text_until_cursor = self.text_until_cursor
 
         # for foo etc, try also to find completer for %foo
         if not cmd.startswith(self.magic_escape):
             try_magic = self.custom_completers.s_matches(
                 self.magic_escape + cmd)
         else:
             try_magic = []
 
         for c in itertools.chain(self.custom_completers.s_matches(cmd),
                  try_magic,
                  self.custom_completers.flat_matches(self.text_until_cursor)):
             try:
                 res = c(event)
                 if res:
                     # first, try case sensitive match
                     withcase = [r for r in res if r.startswith(text)]
                     if withcase:
                         return withcase
                     # if none, then case insensitive ones are ok too
                     text_low = text.lower()
                     return [r for r in res if r.lower().startswith(text_low)]
             except TryNext:
                 pass
             except KeyboardInterrupt:
                 """
                 If custom completer take too long,
                 let keyboard interrupt abort and return nothing.
                 """
                 break
 
         return None
 
     def completions(self, text: str, offset: int)->Iterator[Completion]:
         """
         Returns an iterator over the possible completions
 
         .. warning::
 
             Unstable
 
             This function is unstable, API may change without warning.
             It will also raise unless use in proper context manager.
 
         Parameters
         ----------
         text : str
             Full text of the current input, multi line string.
         offset : int
             Integer representing the position of the cursor in ``text``. Offset
             is 0-based indexed.
 
         Yields
         ------
         Completion
 
         Notes
         -----
         The cursor on a text can either be seen as being "in between"
         characters or "On" a character depending on the interface visible to
         the user. For consistency the cursor being on "in between" characters X
         and Y is equivalent to the cursor being "on" character Y, that is to say
         the character the cursor is on is considered as being after the cursor.
 
         Combining characters may span more that one position in the
         text.
 
         .. note::
 
             If ``IPCompleter.debug`` is :any:`True` will yield a ``--jedi/ipython--``
             fake Completion token to distinguish completion returned by Jedi
             and usual IPython completion.
 
         .. note::
 
             Completions are not completely deduplicated yet. If identical
             completions are coming from different sources this function does not
             ensure that each completion object will only be present once.
         """
         warnings.warn("_complete is a provisional API (as of IPython 6.0). "
                       "It may change without warnings. "
                       "Use in corresponding context manager.",
                       category=ProvisionalCompleterWarning, stacklevel=2)
 
         seen = set()
         profiler:Optional[cProfile.Profile]
         try:
             if self.profile_completions:
                 import cProfile
                 profiler = cProfile.Profile()
                 profiler.enable()
             else:
                 profiler = None
 
             for c in self._completions(text, offset, _timeout=self.jedi_compute_type_timeout/1000):
                 if c and (c in seen):
                     continue
                 yield c
                 seen.add(c)
         except KeyboardInterrupt:
             """if completions take too long and users send keyboard interrupt,
             do not crash and return ASAP. """
             pass
         finally:
             if profiler is not None:
                 profiler.disable()
                 ensure_dir_exists(self.profiler_output_dir)
                 output_path = os.path.join(self.profiler_output_dir, str(uuid.uuid4()))
                 print("Writing profiler output to", output_path)
                 profiler.dump_stats(output_path)
 
     def _completions(self, full_text: str, offset: int, *, _timeout) -> Iterator[Completion]:
         """
         Core completion module.Same signature as :any:`completions`, with the
         extra `timeout` parameter (in seconds).
 
         Computing jedi's completion ``.type`` can be quite expensive (it is a
         lazy property) and can require some warm-up, more warm up than just
         computing the ``name`` of a completion. The warm-up can be :
 
             - Long warm-up the first time a module is encountered after
             install/update: actually build parse/inference tree.
 
             - first time the module is encountered in a session: load tree from
             disk.
 
         We don't want to block completions for tens of seconds so we give the
         completer a "budget" of ``_timeout`` seconds per invocation to compute
         completions types, the completions that have not yet been computed will
         be marked as "unknown" an will have a chance to be computed next round
         are things get cached.
 
         Keep in mind that Jedi is not the only thing treating the completion so
         keep the timeout short-ish as if we take more than 0.3 second we still
         have lots of processing to do.
 
         """
         deadline = time.monotonic() + _timeout
 
         before = full_text[:offset]
         cursor_line, cursor_column = position_to_cursor(full_text, offset)
 
         jedi_matcher_id = _get_matcher_id(self._jedi_matcher)
 
         def is_non_jedi_result(
             result: MatcherResult, identifier: str
         ) -> TypeGuard[SimpleMatcherResult]:
             return identifier != jedi_matcher_id
 
         results = self._complete(
             full_text=full_text, cursor_line=cursor_line, cursor_pos=cursor_column
         )
 
         non_jedi_results: Dict[str, SimpleMatcherResult] = {
             identifier: result
             for identifier, result in results.items()
             if is_non_jedi_result(result, identifier)
         }
 
         jedi_matches = (
             cast(_JediMatcherResult, results[jedi_matcher_id])["completions"]
             if jedi_matcher_id in results
             else ()
         )
 
         iter_jm = iter(jedi_matches)
         if _timeout:
             for jm in iter_jm:
                 try:
                     type_ = jm.type
                 except Exception:
                     if self.debug:
                         print("Error in Jedi getting type of ", jm)
                     type_ = None
                 delta = len(jm.name_with_symbols) - len(jm.complete)
                 if type_ == 'function':
                     signature = _make_signature(jm)
                 else:
                     signature = ''
                 yield Completion(start=offset - delta,
                                  end=offset,
                                  text=jm.name_with_symbols,
                                  type=type_,
                                  signature=signature,
                                  _origin='jedi')
 
                 if time.monotonic() > deadline:
                     break
 
         for jm in iter_jm:
             delta = len(jm.name_with_symbols) - len(jm.complete)
             yield Completion(
                 start=offset - delta,
                 end=offset,
                 text=jm.name_with_symbols,
                 type=_UNKNOWN_TYPE,  # don't compute type for speed
                 _origin="jedi",
                 signature="",
             )
 
         # TODO:
         # Suppress this, right now just for debug.
         if jedi_matches and non_jedi_results and self.debug:
             some_start_offset = before.rfind(
                 next(iter(non_jedi_results.values()))["matched_fragment"]
             )
             yield Completion(
                 start=some_start_offset,
                 end=offset,
                 text="--jedi/ipython--",
                 _origin="debug",
                 type="none",
                 signature="",
             )
 
         ordered: List[Completion] = []
         sortable: List[Completion] = []
 
         for origin, result in non_jedi_results.items():
             matched_text = result["matched_fragment"]
             start_offset = before.rfind(matched_text)
             is_ordered = result.get("ordered", False)
             container = ordered if is_ordered else sortable
 
             # I'm unsure if this is always true, so let's assert and see if it
             # crash
             assert before.endswith(matched_text)
 
             for simple_completion in result["completions"]:
                 completion = Completion(
                     start=start_offset,
                     end=offset,
                     text=simple_completion.text,
                     _origin=origin,
                     signature="",
                     type=simple_completion.type or _UNKNOWN_TYPE,
                 )
                 container.append(completion)
 
         yield from list(self._deduplicate(ordered + self._sort(sortable)))[
             :MATCHES_LIMIT
         ]
 
     def complete(self, text=None, line_buffer=None, cursor_pos=None) -> Tuple[str, Sequence[str]]:
         """Find completions for the given text and line context.
 
         Note that both the text and the line_buffer are optional, but at least
         one of them must be given.
 
         Parameters
         ----------
         text : string, optional
             Text to perform the completion on.  If not given, the line buffer
             is split using the instance's CompletionSplitter object.
         line_buffer : string, optional
             If not given, the completer attempts to obtain the current line
             buffer via readline.  This keyword allows clients which are
             requesting for text completions in non-readline contexts to inform
             the completer of the entire text.
         cursor_pos : int, optional
             Index of the cursor in the full line buffer.  Should be provided by
             remote frontends where kernel has no access to frontend state.
 
         Returns
         -------
         Tuple of two items:
         text : str
             Text that was actually used in the completion.
         matches : list
             A list of completion matches.
 
         Notes
         -----
             This API is likely to be deprecated and replaced by
             :any:`IPCompleter.completions` in the future.
 
         """
         warnings.warn('`Completer.complete` is pending deprecation since '
                 'IPython 6.0 and will be replaced by `Completer.completions`.',
                       PendingDeprecationWarning)
         # potential todo, FOLD the 3rd throw away argument of _complete
         # into the first 2 one.
         # TODO: Q: does the above refer to jedi completions (i.e. 0-indexed?)
         # TODO: should we deprecate now, or does it stay?
 
         results = self._complete(
             line_buffer=line_buffer, cursor_pos=cursor_pos, text=text, cursor_line=0
         )
 
         jedi_matcher_id = _get_matcher_id(self._jedi_matcher)
 
         return self._arrange_and_extract(
             results,
             # TODO: can we confirm that excluding Jedi here was a deliberate choice in previous version?
             skip_matchers={jedi_matcher_id},
             # this API does not support different start/end positions (fragments of token).
             abort_if_offset_changes=True,
         )
 
     def _arrange_and_extract(
         self,
         results: Dict[str, MatcherResult],
         skip_matchers: Set[str],
         abort_if_offset_changes: bool,
     ):
 
         sortable: List[AnyMatcherCompletion] = []
         ordered: List[AnyMatcherCompletion] = []
         most_recent_fragment = None
         for identifier, result in results.items():
             if identifier in skip_matchers:
                 continue
             if not result["completions"]:
                 continue
             if not most_recent_fragment:
                 most_recent_fragment = result["matched_fragment"]
             if (
                 abort_if_offset_changes
                 and result["matched_fragment"] != most_recent_fragment
             ):
                 break
             if result.get("ordered", False):
                 ordered.extend(result["completions"])
             else:
                 sortable.extend(result["completions"])
 
         if not most_recent_fragment:
             most_recent_fragment = ""  # to satisfy typechecker (and just in case)
 
         return most_recent_fragment, [
             m.text for m in self._deduplicate(ordered + self._sort(sortable))
         ]
 
     def _complete(self, *, cursor_line, cursor_pos, line_buffer=None, text=None,
                   full_text=None) -> _CompleteResult:
         """
         Like complete but can also returns raw jedi completions as well as the
         origin of the completion text. This could (and should) be made much
         cleaner but that will be simpler once we drop the old (and stateful)
         :any:`complete` API.
 
         With current provisional API, cursor_pos act both (depending on the
         caller) as the offset in the ``text`` or ``line_buffer``, or as the
         ``column`` when passing multiline strings this could/should be renamed
         but would add extra noise.
 
         Parameters
         ----------
         cursor_line
             Index of the line the cursor is on. 0 indexed.
         cursor_pos
             Position of the cursor in the current line/line_buffer/text. 0
             indexed.
         line_buffer : optional, str
             The current line the cursor is in, this is mostly due to legacy
             reason that readline could only give a us the single current line.
             Prefer `full_text`.
         text : str
             The current "token" the cursor is in, mostly also for historical
             reasons. as the completer would trigger only after the current line
             was parsed.
         full_text : str
             Full text of the current cell.
 
         Returns
         -------
         An ordered dictionary where keys are identifiers of completion
         matchers and values are ``MatcherResult``s.
         """
 
         # if the cursor position isn't given, the only sane assumption we can
         # make is that it's at the end of the line (the common case)
         if cursor_pos is None:
             cursor_pos = len(line_buffer) if text is None else len(text)
 
         if self.use_main_ns:
             self.namespace = __main__.__dict__
 
         # if text is either None or an empty string, rely on the line buffer
         if (not line_buffer) and full_text:
             line_buffer = full_text.split('\n')[cursor_line]
         if not text:  # issue #11508: check line_buffer before calling split_line
             text = (
                 self.splitter.split_line(line_buffer, cursor_pos) if line_buffer else ""
             )
 
         # If no line buffer is given, assume the input text is all there was
         if line_buffer is None:
             line_buffer = text
 
         # deprecated - do not use `line_buffer` in new code.
         self.line_buffer = line_buffer
         self.text_until_cursor = self.line_buffer[:cursor_pos]
 
         if not full_text:
             full_text = line_buffer
 
         context = CompletionContext(
             full_text=full_text,
             cursor_position=cursor_pos,
             cursor_line=cursor_line,
             token=text,
             limit=MATCHES_LIMIT,
         )
 
         # Start with a clean slate of completions
         results: Dict[str, MatcherResult] = {}
 
         jedi_matcher_id = _get_matcher_id(self._jedi_matcher)
 
         suppressed_matchers: Set[str] = set()
 
         matchers = {
             _get_matcher_id(matcher): matcher
             for matcher in sorted(
                 self.matchers, key=_get_matcher_priority, reverse=True
             )
         }
 
         for matcher_id, matcher in matchers.items():
             matcher_id = _get_matcher_id(matcher)
 
             if matcher_id in self.disable_matchers:
                 continue
 
             if matcher_id in results:
                 warnings.warn(f"Duplicate matcher ID: {matcher_id}.")
 
             if matcher_id in suppressed_matchers:
                 continue
 
             result: MatcherResult
             try:
                 if _is_matcher_v1(matcher):
                     result = _convert_matcher_v1_result_to_v2(
                         matcher(text), type=_UNKNOWN_TYPE
                     )
                 elif _is_matcher_v2(matcher):
                     result = matcher(context)
                 else:
                     api_version = _get_matcher_api_version(matcher)
                     raise ValueError(f"Unsupported API version {api_version}")
             except:
                 # Show the ugly traceback if the matcher causes an
                 # exception, but do NOT crash the kernel!
                 sys.excepthook(*sys.exc_info())
                 continue
 
             # set default value for matched fragment if suffix was not selected.
             result["matched_fragment"] = result.get("matched_fragment", context.token)
 
             if not suppressed_matchers:
                 suppression_recommended: Union[bool, Set[str]] = result.get(
                     "suppress", False
                 )
 
                 suppression_config = (
                     self.suppress_competing_matchers.get(matcher_id, None)
                     if isinstance(self.suppress_competing_matchers, dict)
                     else self.suppress_competing_matchers
                 )
                 should_suppress = (
                     (suppression_config is True)
                     or (suppression_recommended and (suppression_config is not False))
                 ) and has_any_completions(result)
 
                 if should_suppress:
                     suppression_exceptions: Set[str] = result.get(
                         "do_not_suppress", set()
                     )
                     if isinstance(suppression_recommended, Iterable):
                         to_suppress = set(suppression_recommended)
                     else:
                         to_suppress = set(matchers)
                     suppressed_matchers = to_suppress - suppression_exceptions
 
                     new_results = {}
                     for previous_matcher_id, previous_result in results.items():
                         if previous_matcher_id not in suppressed_matchers:
                             new_results[previous_matcher_id] = previous_result
                     results = new_results
 
             results[matcher_id] = result
 
         _, matches = self._arrange_and_extract(
             results,
             # TODO Jedi completions non included in legacy stateful API; was this deliberate or omission?
             #  if it was omission, we can remove the filtering step, otherwise remove this comment.
             skip_matchers={jedi_matcher_id},
             abort_if_offset_changes=False,
         )
 
         # populate legacy stateful API
         self.matches = matches
 
         return results
 
     @staticmethod
     def _deduplicate(
         matches: Sequence[AnyCompletion],
     ) -> Iterable[AnyCompletion]:
         filtered_matches: Dict[str, AnyCompletion] = {}
         for match in matches:
             text = match.text
             if (
                 text not in filtered_matches
                 or filtered_matches[text].type == _UNKNOWN_TYPE
             ):
                 filtered_matches[text] = match
 
         return filtered_matches.values()
 
     @staticmethod
     def _sort(matches: Sequence[AnyCompletion]):
         return sorted(matches, key=lambda x: completions_sorting_key(x.text))
 
     @context_matcher()
     def fwd_unicode_matcher(self, context: CompletionContext):
         """Same as :any:`fwd_unicode_match`, but adopted to new Matcher API."""
         # TODO: use `context.limit` to terminate early once we matched the maximum
         #  number that will be used downstream; can be added as an optional to
         #  `fwd_unicode_match(text: str, limit: int = None)` or we could re-implement here.
         fragment, matches = self.fwd_unicode_match(context.text_until_cursor)
         return _convert_matcher_v1_result_to_v2(
             matches, type="unicode", fragment=fragment, suppress_if_matches=True
         )
 
     def fwd_unicode_match(self, text: str) -> Tuple[str, Sequence[str]]:
         """
         Forward match a string starting with a backslash with a list of
         potential Unicode completions.
 
         Will compute list of Unicode character names on first call and cache it.
 
         .. deprecated:: 8.6
             You can use :meth:`fwd_unicode_matcher` instead.
 
         Returns
         -------
         At tuple with:
             - matched text (empty if no matches)
             - list of potential completions, empty tuple  otherwise)
         """
         # TODO: self.unicode_names is here a list we traverse each time with ~100k elements.
         # We could do a faster match using a Trie.
 
         # Using pygtrie the following seem to work:
 
         #     s = PrefixSet()
 
         #     for c in range(0,0x10FFFF + 1):
         #         try:
         #             s.add(unicodedata.name(chr(c)))
         #         except ValueError:
         #             pass
         #     [''.join(k) for k in s.iter(prefix)]
 
         # But need to be timed and adds an extra dependency.
 
         slashpos = text.rfind('\\')
         # if text starts with slash
         if slashpos > -1:
             # PERF: It's important that we don't access self._unicode_names
             # until we're inside this if-block. _unicode_names is lazily
             # initialized, and it takes a user-noticeable amount of time to
             # initialize it, so we don't want to initialize it unless we're
             # actually going to use it.
             s = text[slashpos + 1 :]
             sup = s.upper()
             candidates = [x for x in self.unicode_names if x.startswith(sup)]
             if candidates:
                 return s, candidates
             candidates = [x for x in self.unicode_names if sup in x]
             if candidates:
                 return s, candidates
             splitsup = sup.split(" ")
             candidates = [
                 x for x in self.unicode_names if all(u in x for u in splitsup)
             ]
             if candidates:
                 return s, candidates
 
             return "", ()
 
         # if text does not start with slash
         else:
             return '', ()
 
     @property
     def unicode_names(self) -> List[str]:
         """List of names of unicode code points that can be completed.
 
         The list is lazily initialized on first access.
         """
         if self._unicode_names is None:
             names = []
             for c in range(0,0x10FFFF + 1):
                 try:
                     names.append(unicodedata.name(chr(c)))
                 except ValueError:
                     pass
             self._unicode_names = _unicode_name_compute(_UNICODE_RANGES)
 
         return self._unicode_names
 
 def _unicode_name_compute(ranges:List[Tuple[int,int]]) -> List[str]:
     names = []
     for start,stop in ranges:
         for c in range(start, stop) :
             try:
                 names.append(unicodedata.name(chr(c)))
             except ValueError:
                 pass
     return names

IPython/core/guarded_eval.py

@@ -1,680 +1,695 b''
 from typing import (
     Any,
     Callable,
     Dict,
     Set,
     Tuple,
     NamedTuple,
     Type,
     Literal,
     Union,
     TYPE_CHECKING,
 )
 import ast
 import builtins
 import collections
 import operator
 import sys
 from functools import cached_property
 from dataclasses import dataclass, field
 
 from IPython.utils.docs import GENERATING_DOCUMENTATION
 from IPython.utils.decorators import undoc
 
 
 if TYPE_CHECKING or GENERATING_DOCUMENTATION:
     from typing_extensions import Protocol
 else:
     # do not require on runtime
     Protocol = object  # requires Python >=3.8
 
 
 @undoc
 class HasGetItem(Protocol):
     def __getitem__(self, key) -> None:
         ...
 
 
 @undoc
 class InstancesHaveGetItem(Protocol):
     def __call__(self, *args, **kwargs) -> HasGetItem:
         ...
 
 
 @undoc
 class HasGetAttr(Protocol):
     def __getattr__(self, key) -> None:
         ...
 
 
 @undoc
 class DoesNotHaveGetAttr(Protocol):
     pass
 
 
 # By default `__getattr__` is not explicitly implemented on most objects
 MayHaveGetattr = Union[HasGetAttr, DoesNotHaveGetAttr]
 
 
 def _unbind_method(func: Callable) -> Union[Callable, None]:
     """Get unbound method for given bound method.
 
     Returns None if cannot get unbound method."""
     owner = getattr(func, "__self__", None)
     owner_class = type(owner)
     name = getattr(func, "__name__", None)
     instance_dict_overrides = getattr(owner, "__dict__", None)
     if (
         owner is not None
         and name
         and (
             not instance_dict_overrides
             or (instance_dict_overrides and name not in instance_dict_overrides)
         )
     ):
         return getattr(owner_class, name)
     return None
 
 
 @undoc
 @dataclass
 class EvaluationPolicy:
     """Definition of evaluation policy."""
 
     allow_locals_access: bool = False
     allow_globals_access: bool = False
     allow_item_access: bool = False
     allow_attr_access: bool = False
     allow_builtins_access: bool = False
     allow_all_operations: bool = False
     allow_any_calls: bool = False
     allowed_calls: Set[Callable] = field(default_factory=set)
 
     def can_get_item(self, value, item):
         return self.allow_item_access
 
     def can_get_attr(self, value, attr):
         return self.allow_attr_access
 
     def can_operate(self, dunders: Tuple[str, ...], a, b=None):
         if self.allow_all_operations:
             return True
 
     def can_call(self, func):
         if self.allow_any_calls:
             return True
 
         if func in self.allowed_calls:
             return True
 
         owner_method = _unbind_method(func)
+
         if owner_method and owner_method in self.allowed_calls:
             return True
 
 
 def _has_original_dunder_external(
     value,
     module_name,
     access_path,
     method_name,
 ):
     try:
         if module_name not in sys.modules:
             return False
         member_type = sys.modules[module_name]
         for attr in access_path:
             member_type = getattr(member_type, attr)
         value_type = type(value)
         if type(value) == member_type:
             return True
+        if method_name == "__getattribute__":
+            # we have to short-circuit here due to an unresolved issue in
+            # `isinstance` implementation: https://bugs.python.org/issue32683
+            return False
         if isinstance(value, member_type):
             method = getattr(value_type, method_name, None)
             member_method = getattr(member_type, method_name, None)
             if member_method == method:
                 return True
     except (AttributeError, KeyError):
         return False
 
 
 def _has_original_dunder(
     value, allowed_types, allowed_methods, allowed_external, method_name
 ):
     # note: Python ignores `__getattr__`/`__getitem__` on instances,
     # we only need to check at class level
     value_type = type(value)
 
     # strict type check passes → no need to check method
     if value_type in allowed_types:
         return True
 
     method = getattr(value_type, method_name, None)
 
-    if not method:
+    if method is None:
         return None
 
     if method in allowed_methods:
         return True
 
     for module_name, *access_path in allowed_external:
         if _has_original_dunder_external(value, module_name, access_path, method_name):
             return True
 
     return False
 
 
 @undoc
 @dataclass
 class SelectivePolicy(EvaluationPolicy):
     allowed_getitem: Set[InstancesHaveGetItem] = field(default_factory=set)
     allowed_getitem_external: Set[Tuple[str, ...]] = field(default_factory=set)
 
     allowed_getattr: Set[MayHaveGetattr] = field(default_factory=set)
     allowed_getattr_external: Set[Tuple[str, ...]] = field(default_factory=set)
 
     allowed_operations: Set = field(default_factory=set)
     allowed_operations_external: Set[Tuple[str, ...]] = field(default_factory=set)
 
     _operation_methods_cache: Dict[str, Set[Callable]] = field(
         default_factory=dict, init=False
     )
 
     def can_get_attr(self, value, attr):
         has_original_attribute = _has_original_dunder(
             value,
             allowed_types=self.allowed_getattr,
             allowed_methods=self._getattribute_methods,
             allowed_external=self.allowed_getattr_external,
             method_name="__getattribute__",
         )
         has_original_attr = _has_original_dunder(
             value,
             allowed_types=self.allowed_getattr,
             allowed_methods=self._getattr_methods,
             allowed_external=self.allowed_getattr_external,
             method_name="__getattr__",
         )
+
         # Many objects do not have `__getattr__`, this is fine
         if has_original_attr is None and has_original_attribute:
             return True
 
         # Accept objects without modifications to `__getattr__` and `__getattribute__`
         return has_original_attr and has_original_attribute
 
-    def get_attr(self, value, attr):
-        if self.can_get_attr(value, attr):
-            return getattr(value, attr)
-
     def can_get_item(self, value, item):
         """Allow accessing `__getiitem__` of allow-listed instances unless it was not modified."""
         return _has_original_dunder(
             value,
             allowed_types=self.allowed_getitem,
             allowed_methods=self._getitem_methods,
             allowed_external=self.allowed_getitem_external,
             method_name="__getitem__",
         )
 
     def can_operate(self, dunders: Tuple[str, ...], a, b=None):
+        objects = [a]
+        if b is not None:
+            objects.append(b)
         return all(
             [
                 _has_original_dunder(
-                    a,
+                    obj,
                     allowed_types=self.allowed_operations,
-                    allowed_methods=self._dunder_methods(dunder),
+                    allowed_methods=self._operator_dunder_methods(dunder),
                     allowed_external=self.allowed_operations_external,
                     method_name=dunder,
                 )
                 for dunder in dunders
+                for obj in objects
             ]
         )
 
-    def _dunder_methods(self, dunder: str) -> Set[Callable]:
+    def _operator_dunder_methods(self, dunder: str) -> Set[Callable]:
         if dunder not in self._operation_methods_cache:
             self._operation_methods_cache[dunder] = self._safe_get_methods(
                 self.allowed_operations, dunder
             )
         return self._operation_methods_cache[dunder]
 
     @cached_property
     def _getitem_methods(self) -> Set[Callable]:
         return self._safe_get_methods(self.allowed_getitem, "__getitem__")
 
     @cached_property
     def _getattr_methods(self) -> Set[Callable]:
         return self._safe_get_methods(self.allowed_getattr, "__getattr__")
 
     @cached_property
     def _getattribute_methods(self) -> Set[Callable]:
         return self._safe_get_methods(self.allowed_getattr, "__getattribute__")
 
     def _safe_get_methods(self, classes, name) -> Set[Callable]:
         return {
             method
             for class_ in classes
             for method in [getattr(class_, name, None)]
             if method
         }
 
 
 class _DummyNamedTuple(NamedTuple):
-    pass
+    """Used internally to retrieve methods of named tuple instance."""
 
 
 class EvaluationContext(NamedTuple):
     #: Local namespace
     locals: dict
     #: Global namespace
     globals: dict
     #: Evaluation policy identifier
     evaluation: Literal[
         "forbidden", "minimal", "limited", "unsafe", "dangerous"
     ] = "forbidden"
     #: Whether the evalution of code takes place inside of a subscript.
     #: Useful for evaluating ``:-1, 'col'`` in ``df[:-1, 'col']``.
     in_subscript: bool = False
 
 
 class _IdentitySubscript:
     """Returns the key itself when item is requested via subscript."""
 
     def __getitem__(self, key):
         return key
 
 
 IDENTITY_SUBSCRIPT = _IdentitySubscript()
 SUBSCRIPT_MARKER = "__SUBSCRIPT_SENTINEL__"
 
 
 class GuardRejection(Exception):
     """Exception raised when guard rejects evaluation attempt."""
 
     pass
 
 
 def guarded_eval(code: str, context: EvaluationContext):
     """Evaluate provided code in the evaluation context.
 
     If evaluation policy given by context is set to ``forbidden``
     no evaluation will be performed; if it is set to ``dangerous``
     standard :func:`eval` will be used; finally, for any other,
     policy :func:`eval_node` will be called on parsed AST.
     """
     locals_ = context.locals
 
     if context.evaluation == "forbidden":
         raise GuardRejection("Forbidden mode")
 
     # note: not using `ast.literal_eval` as it does not implement
     # getitem at all, for example it fails on simple `[0][1]`
 
     if context.in_subscript:
         # syntatic sugar for ellipsis (:) is only available in susbcripts
         # so we need to trick the ast parser into thinking that we have
         # a subscript, but we need to be able to later recognise that we did
         # it so we can ignore the actual __getitem__ operation
         if not code:
             return tuple()
         locals_ = locals_.copy()
         locals_[SUBSCRIPT_MARKER] = IDENTITY_SUBSCRIPT
         code = SUBSCRIPT_MARKER + "[" + code + "]"
         context = EvaluationContext(**{**context._asdict(), **{"locals": locals_}})
 
     if context.evaluation == "dangerous":
         return eval(code, context.globals, context.locals)
 
     expression = ast.parse(code, mode="eval")
 
     return eval_node(expression, context)
 
 
 BINARY_OP_DUNDERS: Dict[Type[ast.operator], Tuple[str]] = {
     ast.Add: ("__add__",),
     ast.Sub: ("__sub__",),
     ast.Mult: ("__mul__",),
     ast.Div: ("__truediv__",),
     ast.FloorDiv: ("__floordiv__",),
     ast.Mod: ("__mod__",),
     ast.Pow: ("__pow__",),
     ast.LShift: ("__lshift__",),
     ast.RShift: ("__rshift__",),
     ast.BitOr: ("__or__",),
     ast.BitXor: ("__xor__",),
     ast.BitAnd: ("__and__",),
     ast.MatMult: ("__matmul__",),
 }
 
 COMP_OP_DUNDERS: Dict[Type[ast.cmpop], Tuple[str, ...]] = {
     ast.Eq: ("__eq__",),
     ast.NotEq: ("__ne__", "__eq__"),
     ast.Lt: ("__lt__", "__gt__"),
     ast.LtE: ("__le__", "__ge__"),
     ast.Gt: ("__gt__", "__lt__"),
     ast.GtE: ("__ge__", "__le__"),
     ast.In: ("__contains__",),
     # Note: ast.Is, ast.IsNot, ast.NotIn are handled specially
 }
 
 UNARY_OP_DUNDERS: Dict[Type[ast.unaryop], Tuple[str, ...]] = {
     ast.USub: ("__neg__",),
     ast.UAdd: ("__pos__",),
     # we have to check both __inv__ and __invert__!
     ast.Invert: ("__invert__", "__inv__"),
     ast.Not: ("__not__",),
 }
 
 
 def _find_dunder(node_op, dunders) -> Union[Tuple[str, ...], None]:
     dunder = None
     for op, candidate_dunder in dunders.items():
         if isinstance(node_op, op):
             dunder = candidate_dunder
     return dunder
 
 
 def eval_node(node: Union[ast.AST, None], context: EvaluationContext):
     """Evaluate AST node in provided context.
 
     Applies evaluation restrictions defined in the context. Currently does not support evaluation of functions with keyword arguments.
 
     Does not evaluate actions that always have side effects:
 
     - class definitions (``class sth: ...``)
     - function definitions (``def sth: ...``)
     - variable assignments (``x = 1``)
     - augmented assignments (``x += 1``)
     - deletions (``del x``)
 
     Does not evaluate operations which do not return values:
 
     - assertions (``assert x``)
     - pass (``pass``)
     - imports (``import x``)
     - control flow:
 
         - conditionals (``if x:``) except for ternary IfExp (``a if x else b``)
         - loops (``for`` and `while``)
         - exception handling
 
     The purpose of this function is to guard against unwanted side-effects;
     it does not give guarantees on protection from malicious code execution.
     """
     policy = EVALUATION_POLICIES[context.evaluation]
     if node is None:
         return None
     if isinstance(node, ast.Expression):
         return eval_node(node.body, context)
     if isinstance(node, ast.BinOp):
         left = eval_node(node.left, context)
         right = eval_node(node.right, context)
         dunders = _find_dunder(node.op, BINARY_OP_DUNDERS)
         if dunders:
             if policy.can_operate(dunders, left, right):
                 return getattr(left, dunders[0])(right)
             else:
                 raise GuardRejection(
                     f"Operation (`{dunders}`) for",
                     type(left),
                     f"not allowed in {context.evaluation} mode",
                 )
     if isinstance(node, ast.Compare):
         left = eval_node(node.left, context)
         all_true = True
         negate = False
         for op, right in zip(node.ops, node.comparators):
             right = eval_node(right, context)
             dunder = None
             dunders = _find_dunder(op, COMP_OP_DUNDERS)
             if not dunders:
                 if isinstance(op, ast.NotIn):
                     dunders = COMP_OP_DUNDERS[ast.In]
                     negate = True
                 if isinstance(op, ast.Is):
                     dunder = "is_"
                 if isinstance(op, ast.IsNot):
                     dunder = "is_"
                     negate = True
             if not dunder and dunders:
                 dunder = dunders[0]
             if dunder:
                 a, b = (right, left) if dunder == "__contains__" else (left, right)
                 if dunder == "is_" or dunders and policy.can_operate(dunders, a, b):
                     result = getattr(operator, dunder)(a, b)
                     if negate:
                         result = not result
                     if not result:
                         all_true = False
                     left = right
                 else:
                     raise GuardRejection(
                         f"Comparison (`{dunder}`) for",
                         type(left),
                         f"not allowed in {context.evaluation} mode",
                     )
             else:
-                raise ValueError(f"Comparison `{dunder}` not supported")
+                raise ValueError(
+                    f"Comparison `{dunder}` not supported"
+                )  # pragma: no cover
         return all_true
     if isinstance(node, ast.Constant):
         return node.value
     if isinstance(node, ast.Index):
-        return eval_node(node.value, context)
+        # deprecated since Python 3.9
+        return eval_node(node.value, context)  # pragma: no cover
     if isinstance(node, ast.Tuple):
         return tuple(eval_node(e, context) for e in node.elts)
     if isinstance(node, ast.List):
         return [eval_node(e, context) for e in node.elts]
     if isinstance(node, ast.Set):
         return {eval_node(e, context) for e in node.elts}
     if isinstance(node, ast.Dict):
         return dict(
             zip(
                 [eval_node(k, context) for k in node.keys],
                 [eval_node(v, context) for v in node.values],
             )
         )
     if isinstance(node, ast.Slice):
         return slice(
             eval_node(node.lower, context),
             eval_node(node.upper, context),
             eval_node(node.step, context),
         )
     if isinstance(node, ast.ExtSlice):
-        return tuple([eval_node(dim, context) for dim in node.dims])
+        # deprecated since Python 3.9
+        return tuple([eval_node(dim, context) for dim in node.dims])  # pragma: no cover
     if isinstance(node, ast.UnaryOp):
         value = eval_node(node.operand, context)
         dunders = _find_dunder(node.op, UNARY_OP_DUNDERS)
         if dunders:
             if policy.can_operate(dunders, value):
                 return getattr(value, dunders[0])()
             else:
                 raise GuardRejection(
                     f"Operation (`{dunders}`) for",
                     type(value),
                     f"not allowed in {context.evaluation} mode",
                 )
-        raise ValueError("Unhandled unary operation:", node.op)
     if isinstance(node, ast.Subscript):
         value = eval_node(node.value, context)
         slice_ = eval_node(node.slice, context)
         if policy.can_get_item(value, slice_):
             return value[slice_]
         raise GuardRejection(
             "Subscript access (`__getitem__`) for",
             type(value),  # not joined to avoid calling `repr`
             f" not allowed in {context.evaluation} mode",
         )
     if isinstance(node, ast.Name):
         if policy.allow_locals_access and node.id in context.locals:
             return context.locals[node.id]
         if policy.allow_globals_access and node.id in context.globals:
             return context.globals[node.id]
         if policy.allow_builtins_access and hasattr(builtins, node.id):
-            # note: do not use __builtins__, it is implementation detail of Python
+            # note: do not use __builtins__, it is implementation detail of cPython
             return getattr(builtins, node.id)
         if not policy.allow_globals_access and not policy.allow_locals_access:
             raise GuardRejection(
                 f"Namespace access not allowed in {context.evaluation} mode"
             )
         else:
-            raise NameError(f"{node.id} not found in locals nor globals")
+            raise NameError(f"{node.id} not found in locals, globals, nor builtins")
     if isinstance(node, ast.Attribute):
         value = eval_node(node.value, context)
         if policy.can_get_attr(value, node.attr):
             return getattr(value, node.attr)
         raise GuardRejection(
             "Attribute access (`__getattr__`) for",
             type(value),  # not joined to avoid calling `repr`
             f"not allowed in {context.evaluation} mode",
         )
     if isinstance(node, ast.IfExp):
         test = eval_node(node.test, context)
         if test:
             return eval_node(node.body, context)
         else:
             return eval_node(node.orelse, context)
     if isinstance(node, ast.Call):
         func = eval_node(node.func, context)
         if policy.can_call(func) and not node.keywords:
             args = [eval_node(arg, context) for arg in node.args]
             return func(*args)
         raise GuardRejection(
             "Call for",
             func,  # not joined to avoid calling `repr`
             f"not allowed in {context.evaluation} mode",
         )
-    raise ValueError("Unhandled node", node)
+    raise ValueError("Unhandled node", ast.dump(node))
 
 
 SUPPORTED_EXTERNAL_GETITEM = {
     ("pandas", "core", "indexing", "_iLocIndexer"),
     ("pandas", "core", "indexing", "_LocIndexer"),
     ("pandas", "DataFrame"),
     ("pandas", "Series"),
     ("numpy", "ndarray"),
     ("numpy", "void"),
 }
 
+
 BUILTIN_GETITEM: Set[InstancesHaveGetItem] = {
     dict,
     str,
     bytes,
     list,
     tuple,
     collections.defaultdict,
     collections.deque,
     collections.OrderedDict,
     collections.ChainMap,
     collections.UserDict,
     collections.UserList,
     collections.UserString,
     _DummyNamedTuple,
     _IdentitySubscript,
 }
 
 
 def _list_methods(cls, source=None):
     """For use on immutable objects or with methods returning a copy"""
     return [getattr(cls, k) for k in (source if source else dir(cls))]
 
 
 dict_non_mutating_methods = ("copy", "keys", "values", "items")
 list_non_mutating_methods = ("copy", "index", "count")
 set_non_mutating_methods = set(dir(set)) & set(dir(frozenset))
 
 
 dict_keys: Type[collections.abc.KeysView] = type({}.keys())
 method_descriptor: Any = type(list.copy)
 
+NUMERICS = {int, float, complex}
+
 ALLOWED_CALLS = {
     bytes,
     *_list_methods(bytes),
     dict,
     *_list_methods(dict, dict_non_mutating_methods),
     dict_keys.isdisjoint,
     list,
     *_list_methods(list, list_non_mutating_methods),
     set,
     *_list_methods(set, set_non_mutating_methods),
     frozenset,
     *_list_methods(frozenset),
     range,
     str,
     *_list_methods(str),
     tuple,
     *_list_methods(tuple),
+    *NUMERICS,
+    *[method for numeric_cls in NUMERICS for method in _list_methods(numeric_cls)],
     collections.deque,
     *_list_methods(collections.deque, list_non_mutating_methods),
     collections.defaultdict,
     *_list_methods(collections.defaultdict, dict_non_mutating_methods),
     collections.OrderedDict,
     *_list_methods(collections.OrderedDict, dict_non_mutating_methods),
     collections.UserDict,
     *_list_methods(collections.UserDict, dict_non_mutating_methods),
     collections.UserList,
     *_list_methods(collections.UserList, list_non_mutating_methods),
     collections.UserString,
     *_list_methods(collections.UserString, dir(str)),
     collections.Counter,
     *_list_methods(collections.Counter, dict_non_mutating_methods),
     collections.Counter.elements,
     collections.Counter.most_common,
 }
 
 BUILTIN_GETATTR: Set[MayHaveGetattr] = {
     *BUILTIN_GETITEM,
     set,
     frozenset,
     object,
     type,  # `type` handles a lot of generic cases, e.g. numbers as in `int.real`.
+    *NUMERICS,
     dict_keys,
     method_descriptor,
 }
 
 
-BUILTIN_OPERATIONS = {int, float, complex, *BUILTIN_GETATTR}
+BUILTIN_OPERATIONS = {*BUILTIN_GETATTR}
 
 EVALUATION_POLICIES = {
     "minimal": EvaluationPolicy(
         allow_builtins_access=True,
         allow_locals_access=False,
         allow_globals_access=False,
         allow_item_access=False,
         allow_attr_access=False,
         allowed_calls=set(),
         allow_any_calls=False,
         allow_all_operations=False,
     ),
     "limited": SelectivePolicy(
         # TODO:
         # - should reject binary and unary operations if custom methods would be dispatched
         allowed_getitem=BUILTIN_GETITEM,
         allowed_getitem_external=SUPPORTED_EXTERNAL_GETITEM,
         allowed_getattr=BUILTIN_GETATTR,
         allowed_getattr_external={
             # pandas Series/Frame implements custom `__getattr__`
             ("pandas", "DataFrame"),
             ("pandas", "Series"),
         },
         allowed_operations=BUILTIN_OPERATIONS,
         allow_builtins_access=True,
         allow_locals_access=True,
         allow_globals_access=True,
         allowed_calls=ALLOWED_CALLS,
     ),
     "unsafe": EvaluationPolicy(
         allow_builtins_access=True,
         allow_locals_access=True,
         allow_globals_access=True,
         allow_attr_access=True,
         allow_item_access=True,
         allow_any_calls=True,
         allow_all_operations=True,
     ),
 }
 
 
 __all__ = [
     "guarded_eval",
     "eval_node",
     "GuardRejection",
     "EvaluationContext",
     "_unbind_method",
 ]

IPython/core/tests/test_guarded_eval.py

@@ -1,331 +1,492 b''
 from typing import NamedTuple
+from functools import partial
 from IPython.core.guarded_eval import (
     EvaluationContext,
     GuardRejection,
     guarded_eval,
     _unbind_method,
 )
 from IPython.testing import decorators as dec
 import pytest
 
 
-def limited(**kwargs):
-    return EvaluationContext(locals=kwargs, globals={}, evaluation="limited")
+def create_context(evaluation: str, **kwargs):
+    return EvaluationContext(locals=kwargs, globals={}, evaluation=evaluation)
 
 
-def unsafe(**kwargs):
-    return EvaluationContext(locals=kwargs, globals={}, evaluation="unsafe")
+forbidden = partial(create_context, "forbidden")
+minimal = partial(create_context, "minimal")
+limited = partial(create_context, "limited")
+unsafe = partial(create_context, "unsafe")
+dangerous = partial(create_context, "dangerous")
+
+LIMITED_OR_HIGHER = [limited, unsafe, dangerous]
+
+MINIMAL_OR_HIGHER = [minimal, *LIMITED_OR_HIGHER]
 
 
 @dec.skip_without("pandas")
 def test_pandas_series_iloc():
     import pandas as pd
 
     series = pd.Series([1], index=["a"])
     context = limited(data=series)
     assert guarded_eval("data.iloc[0]", context) == 1
 
 
 @dec.skip_without("pandas")
 def test_pandas_series():
     import pandas as pd
 
     context = limited(data=pd.Series([1], index=["a"]))
     assert guarded_eval('data["a"]', context) == 1
     with pytest.raises(KeyError):
         guarded_eval('data["c"]', context)
 
 
 @dec.skip_without("pandas")
 def test_pandas_bad_series():
     import pandas as pd
 
     class BadItemSeries(pd.Series):
         def __getitem__(self, key):
             return "CUSTOM_ITEM"
 
     class BadAttrSeries(pd.Series):
         def __getattr__(self, key):
             return "CUSTOM_ATTR"
 
     bad_series = BadItemSeries([1], index=["a"])
     context = limited(data=bad_series)
 
     with pytest.raises(GuardRejection):
         guarded_eval('data["a"]', context)
     with pytest.raises(GuardRejection):
         guarded_eval('data["c"]', context)
 
     # note: here result is a bit unexpected because
     # pandas `__getattr__` calls `__getitem__`;
     # FIXME - special case to handle it?
     assert guarded_eval("data.a", context) == "CUSTOM_ITEM"
 
     context = unsafe(data=bad_series)
     assert guarded_eval('data["a"]', context) == "CUSTOM_ITEM"
 
     bad_attr_series = BadAttrSeries([1], index=["a"])
     context = limited(data=bad_attr_series)
     assert guarded_eval('data["a"]', context) == 1
     with pytest.raises(GuardRejection):
         guarded_eval("data.a", context)
 
 
 @dec.skip_without("pandas")
 def test_pandas_dataframe_loc():
     import pandas as pd
     from pandas.testing import assert_series_equal
 
     data = pd.DataFrame([{"a": 1}])
     context = limited(data=data)
     assert_series_equal(guarded_eval('data.loc[:, "a"]', context), data["a"])
 
 
 def test_named_tuple():
     class GoodNamedTuple(NamedTuple):
         a: str
         pass
 
     class BadNamedTuple(NamedTuple):
         a: str
 
         def __getitem__(self, key):
             return None
 
     good = GoodNamedTuple(a="x")
     bad = BadNamedTuple(a="x")
 
     context = limited(data=good)
     assert guarded_eval("data[0]", context) == "x"
 
     context = limited(data=bad)
     with pytest.raises(GuardRejection):
         guarded_eval("data[0]", context)
 
 
 def test_dict():
     context = limited(data={"a": 1, "b": {"x": 2}, ("x", "y"): 3})
     assert guarded_eval('data["a"]', context) == 1
     assert guarded_eval('data["b"]', context) == {"x": 2}
     assert guarded_eval('data["b"]["x"]', context) == 2
     assert guarded_eval('data["x", "y"]', context) == 3
 
     assert guarded_eval("data.keys", context)
 
 
 def test_set():
     context = limited(data={"a", "b"})
     assert guarded_eval("data.difference", context)
 
 
 def test_list():
     context = limited(data=[1, 2, 3])
     assert guarded_eval("data[1]", context) == 2
     assert guarded_eval("data.copy", context)
 
 
 def test_dict_literal():
     context = limited()
     assert guarded_eval("{}", context) == {}
     assert guarded_eval('{"a": 1}', context) == {"a": 1}
 
 
 def test_list_literal():
     context = limited()
     assert guarded_eval("[]", context) == []
     assert guarded_eval('[1, "a"]', context) == [1, "a"]
 
 
 def test_set_literal():
     context = limited()
     assert guarded_eval("set()", context) == set()
     assert guarded_eval('{"a"}', context) == {"a"}
 
 
-def test_if_expression():
+def test_evaluates_if_expression():
     context = limited()
     assert guarded_eval("2 if True else 3", context) == 2
     assert guarded_eval("4 if False else 5", context) == 5
 
 
 def test_object():
     obj = object()
     context = limited(obj=obj)
     assert guarded_eval("obj.__dir__", context) == obj.__dir__
 
 
 @pytest.mark.parametrize(
     "code,expected",
     [
         ["int.numerator", int.numerator],
         ["float.is_integer", float.is_integer],
         ["complex.real", complex.real],
     ],
 )
 def test_number_attributes(code, expected):
     assert guarded_eval(code, limited()) == expected
 
 
 def test_method_descriptor():
     context = limited()
     assert guarded_eval("list.copy.__name__", context) == "copy"
 
 
 @pytest.mark.parametrize(
     "data,good,bad,expected",
     [
         [[1, 2, 3], "data.index(2)", "data.append(4)", 1],
         [{"a": 1}, "data.keys().isdisjoint({})", "data.update()", True],
     ],
 )
-def test_calls(data, good, bad, expected):
+def test_evaluates_calls(data, good, bad, expected):
     context = limited(data=data)
     assert guarded_eval(good, context) == expected
 
     with pytest.raises(GuardRejection):
         guarded_eval(bad, context)
 
 
 @pytest.mark.parametrize(
     "code,expected",
     [
         ["(1\n+\n1)", 2],
         ["list(range(10))[-1:]", [9]],
         ["list(range(20))[3:-2:3]", [3, 6, 9, 12, 15]],
     ],
 )
-def test_literals(code, expected):
-    context = limited()
-    assert guarded_eval(code, context) == expected
[e-mail]("context", LIMITED_OR_HIGHER)
+def test_evaluates_complex_cases(code, expected, context):
+    assert guarded_eval(code, context()) == expected
+
+
[e-mail](
+    "code,expected",
+    [
+        ["1", 1],
+        ["1.0", 1.0],
+        ["0xdeedbeef", 0xDEEDBEEF],
+        ["True", True],
+        ["None", None],
+        ["{}", {}],
+        ["[]", []],
+    ],
+)
[e-mail]("context", MINIMAL_OR_HIGHER)
+def test_evaluates_literals(code, expected, context):
+    assert guarded_eval(code, context()) == expected
 
 
 @pytest.mark.parametrize(
     "code,expected",
     [
         ["-5", -5],
         ["+5", +5],
         ["~5", -6],
     ],
 )
-def test_unary_operations(code, expected):
-    context = limited()
-    assert guarded_eval(code, context) == expected
[e-mail]("context", LIMITED_OR_HIGHER)
+def test_evaluates_unary_operations(code, expected, context):
+    assert guarded_eval(code, context()) == expected
 
 
 @pytest.mark.parametrize(
     "code,expected",
     [
         ["1 + 1", 2],
         ["3 - 1", 2],
         ["2 * 3", 6],
         ["5 // 2", 2],
         ["5 / 2", 2.5],
         ["5**2", 25],
         ["2 >> 1", 1],
         ["2 << 1", 4],
         ["1 | 2", 3],
         ["1 & 1", 1],
         ["1 & 2", 0],
     ],
 )
-def test_binary_operations(code, expected):
-    context = limited()
-    assert guarded_eval(code, context) == expected
[e-mail]("context", LIMITED_OR_HIGHER)
+def test_evaluates_binary_operations(code, expected, context):
+    assert guarded_eval(code, context()) == expected
 
 
 @pytest.mark.parametrize(
     "code,expected",
     [
         ["2 > 1", True],
         ["2 < 1", False],
         ["2 <= 1", False],
         ["2 <= 2", True],
         ["1 >= 2", False],
         ["2 >= 2", True],
         ["2 == 2", True],
         ["1 == 2", False],
         ["1 != 2", True],
         ["1 != 1", False],
         ["1 < 4 < 3", False],
         ["(1 < 4) < 3", True],
         ["4 > 3 > 2 > 1", True],
         ["4 > 3 > 2 > 9", False],
         ["1 < 2 < 3 < 4", True],
         ["9 < 2 < 3 < 4", False],
         ["1 < 2 > 1 > 0 > -1 < 1", True],
         ["1 in [1] in [[1]]", True],
         ["1 in [1] in [[2]]", False],
         ["1 in [1]", True],
         ["0 in [1]", False],
         ["1 not in [1]", False],
         ["0 not in [1]", True],
         ["True is True", True],
         ["False is False", True],
         ["True is False", False],
+        ["True is not True", False],
+        ["False is not True", True],
     ],
 )
-def test_comparisons(code, expected):
-    context = limited()
-    assert guarded_eval(code, context) == expected
[e-mail]("context", LIMITED_OR_HIGHER)
+def test_evaluates_comparisons(code, expected, context):
+    assert guarded_eval(code, context()) == expected
+
+
+def test_guards_comparisons():
+    class GoodEq(int):
+        pass
+
+    class BadEq(int):
+        def __eq__(self, other):
+            assert False
+
+    context = limited(bad=BadEq(1), good=GoodEq(1))
+
+    with pytest.raises(GuardRejection):
+        guarded_eval("bad == 1", context)
+
+    with pytest.raises(GuardRejection):
+        guarded_eval("bad != 1", context)
+
+    with pytest.raises(GuardRejection):
+        guarded_eval("1 == bad", context)
+
+    with pytest.raises(GuardRejection):
+        guarded_eval("1 != bad", context)
+
+    assert guarded_eval("good == 1", context) is True
+    assert guarded_eval("good != 1", context) is False
+    assert guarded_eval("1 == good", context) is True
+    assert guarded_eval("1 != good", context) is False
+
+
+def test_guards_unary_operations():
+    class GoodOp(int):
+        pass
+
+    class BadOpInv(int):
+        def __inv__(self, other):
+            assert False
+
+    class BadOpInverse(int):
+        def __inv__(self, other):
+            assert False
+
+    context = limited(good=GoodOp(1), bad1=BadOpInv(1), bad2=BadOpInverse(1))
+
+    with pytest.raises(GuardRejection):
+        guarded_eval("~bad1", context)
+
+    with pytest.raises(GuardRejection):
+        guarded_eval("~bad2", context)
+
+
+def test_guards_binary_operations():
+    class GoodOp(int):
+        pass
 
+    class BadOp(int):
+        def __add__(self, other):
+            assert False
 
-def test_access_builtins():
+    context = limited(good=GoodOp(1), bad=BadOp(1))
+
+    with pytest.raises(GuardRejection):
+        guarded_eval("1 + bad", context)
+
+    with pytest.raises(GuardRejection):
+        guarded_eval("bad + 1", context)
+
+    assert guarded_eval("good + 1", context) == 2
+    assert guarded_eval("1 + good", context) == 2
+
+
+def test_guards_attributes():
+    class GoodAttr(float):
+        pass
+
+    class BadAttr1(float):
+        def __getattr__(self, key):
+            assert False
+
+    class BadAttr2(float):
+        def __getattribute__(self, key):
+            assert False
+
+    context = limited(good=GoodAttr(0.5), bad1=BadAttr1(0.5), bad2=BadAttr2(0.5))
+
+    with pytest.raises(GuardRejection):
+        guarded_eval("bad1.as_integer_ratio", context)
+
+    with pytest.raises(GuardRejection):
+        guarded_eval("bad2.as_integer_ratio", context)
+
+    assert guarded_eval("good.as_integer_ratio()", context) == (1, 2)
+
+
[e-mail]("context", MINIMAL_OR_HIGHER)
+def test_access_builtins(context):
+    assert guarded_eval("round", context()) == round
+
+
+def test_access_builtins_fails():
     context = limited()
-    assert guarded_eval("round", context) == round
+    with pytest.raises(NameError):
+        guarded_eval("this_is_not_builtin", context)
+
+
+def test_rejects_forbidden():
+    context = forbidden()
+    with pytest.raises(GuardRejection):
+        guarded_eval("1", context)
+
+
+def test_guards_locals_and_globals():
+    context = EvaluationContext(
+        locals={"local_a": "a"}, globals={"global_b": "b"}, evaluation="minimal"
+    )
+
+    with pytest.raises(GuardRejection):
+        guarded_eval("local_a", context)
+
+    with pytest.raises(GuardRejection):
+        guarded_eval("global_b", context)
+
+
+def test_access_locals_and_globals():
+    context = EvaluationContext(
+        locals={"local_a": "a"}, globals={"global_b": "b"}, evaluation="limited"
+    )
+    assert guarded_eval("local_a", context) == "a"
+    assert guarded_eval("global_b", context) == "b"
+
+
[e-mail](
+    "code",
+    ["def func(): pass", "class C: pass", "x = 1", "x += 1", "del x", "import ast"],
+)
[e-mail]("context", [minimal(), limited(), unsafe()])
+def test_rejects_side_effect_syntax(code, context):
+    with pytest.raises(SyntaxError):
+        guarded_eval(code, context)
 
 
 def test_subscript():
     context = EvaluationContext(
         locals={}, globals={}, evaluation="limited", in_subscript=True
     )
     empty_slice = slice(None, None, None)
     assert guarded_eval("", context) == tuple()
     assert guarded_eval(":", context) == empty_slice
     assert guarded_eval("1:2:3", context) == slice(1, 2, 3)
     assert guarded_eval(':, "a"', context) == (empty_slice, "a")
 
 
 def test_unbind_method():
     class X(list):
         def index(self, k):
             return "CUSTOM"
 
     x = X()
     assert _unbind_method(x.index) is X.index
     assert _unbind_method([].index) is list.index
 
 
 def test_assumption_instance_attr_do_not_matter():
     """This is semi-specified in Python documentation.
 
     However, since the specification says 'not guaranted
     to work' rather than 'is forbidden to work', future
     versions could invalidate this assumptions. This test
     is meant to catch such a change if it ever comes true.
     """
 
     class T:
         def __getitem__(self, k):
             return "a"
 
         def __getattr__(self, k):
             return "a"
 
     t = T()
     t.__getitem__ = lambda f: "b"
     t.__getattr__ = lambda f: "b"
     assert t[1] == "a"
     assert t[1] == "a"
 
 
 def test_assumption_named_tuples_share_getitem():
     """Check assumption on named tuples sharing __getitem__"""
     from typing import NamedTuple
 
     class A(NamedTuple):
         pass
 
     class B(NamedTuple):
         pass
 
     assert A.__getitem__ == B.__getitem__