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- # Copyright (c) 2016-2018 Claudiu Popa <pcmanticore@gmail.com>
- # Copyright (c) 2021 Pierre Sassoulas <pierre.sassoulas@gmail.com>
- # Copyright (c) 2021 Marc Mueller <30130371+cdce8p@users.noreply.github.com>
- # Licensed under the LGPL: https://www.gnu.org/licenses/old-licenses/lgpl-2.1.en.html
- # For details: https://github.com/PyCQA/astroid/blob/main/LICENSE
- """Contains logic for retrieving special methods.
- This implementation does not rely on the dot attribute access
- logic, found in ``.getattr()``. The difference between these two
- is that the dunder methods are looked with the type slots
- (you can find more about these here
- http://lucumr.pocoo.org/2014/8/16/the-python-i-would-like-to-see/)
- As such, the lookup for the special methods is actually simpler than
- the dot attribute access.
- """
- import itertools
- import astroid
- from astroid.exceptions import AttributeInferenceError
- def _lookup_in_mro(node, name):
- attrs = node.locals.get(name, [])
- nodes = itertools.chain.from_iterable(
- ancestor.locals.get(name, []) for ancestor in node.ancestors(recurs=True)
- )
- values = list(itertools.chain(attrs, nodes))
- if not values:
- raise AttributeInferenceError(attribute=name, target=node)
- return values
- def lookup(node, name):
- """Lookup the given special method name in the given *node*
- If the special method was found, then a list of attributes
- will be returned. Otherwise, `astroid.AttributeInferenceError`
- is going to be raised.
- """
- if isinstance(
- node, (astroid.List, astroid.Tuple, astroid.Const, astroid.Dict, astroid.Set)
- ):
- return _builtin_lookup(node, name)
- if isinstance(node, astroid.Instance):
- return _lookup_in_mro(node, name)
- if isinstance(node, astroid.ClassDef):
- return _class_lookup(node, name)
- raise AttributeInferenceError(attribute=name, target=node)
- def _class_lookup(node, name):
- metaclass = node.metaclass()
- if metaclass is None:
- raise AttributeInferenceError(attribute=name, target=node)
- return _lookup_in_mro(metaclass, name)
- def _builtin_lookup(node, name):
- values = node.locals.get(name, [])
- if not values:
- raise AttributeInferenceError(attribute=name, target=node)
- return values
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