name : dict_init_mutate.py # Licensed under the GPL: https://www.gnu.org/licenses/old-licenses/gpl-2.0.html # For details: https://github.com/PyCQA/pylint/blob/main/LICENSE # Copyright (c) https://github.com/PyCQA/pylint/blob/main/CONTRIBUTORS.txt """Check for use of dictionary mutation after initialization.""" from __future__ import annotations from typing import TYPE_CHECKING from astroid import nodes from pylint.checkers import BaseChecker from pylint.checkers.utils import only_required_for_messages from pylint.interfaces import HIGH if TYPE_CHECKING: from pylint.lint.pylinter import PyLinter class DictInitMutateChecker(BaseChecker): name = "dict-init-mutate" msgs = { "C3401": ( "Declare all known key/values when initializing the dictionary.", "dict-init-mutate", "Dictionaries can be initialized with a single statement " "using dictionary literal syntax.", ) } @only_required_for_messages("dict-init-mutate") def visit_assign(self, node: nodes.Assign) -> None: """ Detect dictionary mutation immediately after initialization. At this time, detecting nested mutation is not supported. """ if not isinstance(node.value, nodes.Dict): return dict_name = node.targets[0] if len(node.targets) != 1 or not isinstance(dict_name, nodes.AssignName): return first_sibling = node.next_sibling() if ( not first_sibling or not isinstance(first_sibling, nodes.Assign) or len(first_sibling.targets) != 1 ): return sibling_target = first_sibling.targets[0] if not isinstance(sibling_target, nodes.Subscript): return sibling_name = sibling_target.value if not isinstance(sibling_name, nodes.Name): return if sibling_name.name == dict_name.name: self.add_message("dict-init-mutate", node=node, confidence=HIGH) def register(linter: PyLinter) -> None: linter.register_checker(DictInitMutateChecker(linter))