| # Licensed under the LGPL: https://www.gnu.org/licenses/old-licenses/lgpl-2.1.en.html |
| # For details: https://github.com/pylint-dev/astroid/blob/main/LICENSE |
| # Copyright (c) https://github.com/pylint-dev/astroid/blob/main/CONTRIBUTORS.txt |
| |
| """Transform utilities (filters and decorator).""" |
| |
| from __future__ import annotations |
| |
| from collections import OrderedDict |
| from collections.abc import Generator |
| from typing import Any, TypeVar |
| |
| from astroid.context import InferenceContext |
| from astroid.exceptions import InferenceOverwriteError, UseInferenceDefault |
| from astroid.nodes import NodeNG |
| from astroid.typing import ( |
| InferenceResult, |
| InferFn, |
| TransformFn, |
| ) |
| |
| _cache: OrderedDict[ |
| tuple[InferFn[Any], NodeNG, InferenceContext | None], list[InferenceResult] |
| ] = OrderedDict() |
| |
| _CURRENTLY_INFERRING: set[tuple[InferFn[Any], NodeNG]] = set() |
| |
| _NodesT = TypeVar("_NodesT", bound=NodeNG) |
| |
| |
| def clear_inference_tip_cache() -> None: |
| """Clear the inference tips cache.""" |
| _cache.clear() |
| |
| |
| def _inference_tip_cached(func: InferFn[_NodesT]) -> InferFn[_NodesT]: |
| """Cache decorator used for inference tips.""" |
| |
| def inner( |
| node: _NodesT, |
| context: InferenceContext | None = None, |
| **kwargs: Any, |
| ) -> Generator[InferenceResult, None, None]: |
| partial_cache_key = (func, node) |
| if partial_cache_key in _CURRENTLY_INFERRING: |
| # If through recursion we end up trying to infer the same |
| # func + node we raise here. |
| _CURRENTLY_INFERRING.remove(partial_cache_key) |
| raise UseInferenceDefault |
| if context is not None and context.is_empty(): |
| # Fresh, empty contexts will defeat the cache. |
| context = None |
| try: |
| yield from _cache[func, node, context] |
| return |
| except KeyError: |
| # Recursion guard with a partial cache key. |
| # Using the full key causes a recursion error on PyPy. |
| # It's a pragmatic compromise to avoid so much recursive inference |
| # with slightly different contexts while still passing the simple |
| # test cases included with this commit. |
| _CURRENTLY_INFERRING.add(partial_cache_key) |
| try: |
| # May raise UseInferenceDefault |
| result = _cache[func, node, context] = list( |
| func(node, context, **kwargs) |
| ) |
| except Exception as e: |
| # Suppress the KeyError from the cache miss. |
| raise e from None |
| finally: |
| # Remove recursion guard. |
| try: |
| _CURRENTLY_INFERRING.remove(partial_cache_key) |
| except KeyError: |
| pass # Recursion may beat us to the punch. |
| |
| if len(_cache) > 64: |
| _cache.popitem(last=False) |
| |
| # https://github.com/pylint-dev/pylint/issues/8686 |
| yield from result # pylint: disable=used-before-assignment |
| |
| return inner |
| |
| |
| def inference_tip( |
| infer_function: InferFn[_NodesT], raise_on_overwrite: bool = False |
| ) -> TransformFn[_NodesT]: |
| """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: _NodesT, infer_function: InferFn[_NodesT] = infer_function |
| ) -> _NodesT: |
| 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, |
| ) |
| ) |
| node._explicit_inference = _inference_tip_cached(infer_function) |
| return node |
| |
| return transform |