# 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))
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