# 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
"""Ellipsis checker for Python code."""
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
if TYPE_CHECKING:
from pylint.lint import PyLinter
class EllipsisChecker(BaseChecker):
name = "unnecessary_ellipsis"
msgs = {
"W2301": (
"Unnecessary ellipsis constant",
"unnecessary-ellipsis",
"Used when the ellipsis constant is encountered and can be avoided. "
"A line of code consisting of an ellipsis is unnecessary if "
"there is a docstring on the preceding line or if there is a "
"statement in the same scope.",
)
}
@only_required_for_messages("unnecessary-ellipsis")
def visit_const(self, node: nodes.Const) -> None:
"""Check if the ellipsis constant is used unnecessarily.
Emits a warning when:
- A line consisting of an ellipsis is preceded by a docstring.
- A statement exists in the same scope as the ellipsis.
For example: A function consisting of an ellipsis followed by a
return statement on the next line.
"""
if (
node.pytype() == "builtins.Ellipsis"
and isinstance(node.parent, nodes.Expr)
and (
(
isinstance(node.parent.parent, (nodes.ClassDef, nodes.FunctionDef))
and node.parent.parent.doc_node
)
or len(node.parent.parent.body) > 1
)
):
self.add_message("unnecessary-ellipsis", node=node)
def register(linter: PyLinter) -> None:
linter.register_checker(EllipsisChecker(linter))
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