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# 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
# Copyright (c) https://github.com/PyCQA/astroid/blob/main/CONTRIBUTORS.txt
"""Transform utilities (filters and decorator)."""
from __future__ import annotations
import typing
from collections.abc import Iterator
import wrapt
from astroid.exceptions import InferenceOverwriteError, UseInferenceDefault
from astroid.nodes import NodeNG
from astroid.typing import InferenceResult, InferFn
_cache: dict[tuple[InferFn, NodeNG], list[InferenceResult] | None] = {}
def clear_inference_tip_cache() -> None:
"""Clear the inference tips cache."""
_cache.clear()
@wrapt.decorator
def _inference_tip_cached(
func: InferFn, instance: None, args: typing.Any, kwargs: typing.Any
) -> Iterator[InferenceResult]:
"""Cache decorator used for inference tips."""
node = args[0]
try:
result = _cache[func, node]
# If through recursion we end up trying to infer the same
# func + node we raise here.
if result is None:
raise UseInferenceDefault()
except KeyError:
_cache[func, node] = None
result = _cache[func, node] = list(func(*args, **kwargs))
assert result
return iter(result)
def inference_tip(infer_function: InferFn, raise_on_overwrite: bool = False) -> InferFn:
"""Given an instance specific inference function, return a function to be
given to AstroidManager().register_transform to set this inference function.
:param bool raise_on_overwrite: Raise an `InferenceOverwriteError`
if the inference tip will overwrite another. Used for debugging
Typical usage
.. sourcecode:: python
AstroidManager().register_transform(Call, inference_tip(infer_named_tuple),
predicate)
.. Note::
Using an inference tip will override
any previously set inference tip for the given
node. Use a predicate in the transform to prevent
excess overwrites.
"""
def transform(node: NodeNG, infer_function: InferFn = infer_function) -> NodeNG:
if (
raise_on_overwrite
and node._explicit_inference is not None
and node._explicit_inference is not infer_function
):
raise InferenceOverwriteError(
"Inference already set to {existing_inference}. "
"Trying to overwrite with {new_inference} for {node}".format(
existing_inference=infer_function,
new_inference=node._explicit_inference,
node=node,
)
)
# pylint: disable=no-value-for-parameter
node._explicit_inference = _inference_tip_cached(infer_function)
return node
return transform
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