name : confusing_elif.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 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 ConfusingConsecutiveElifChecker(BaseChecker): """Checks if "elif" is used right after an indented block that finishes with "if" or "elif" itself. """ name = "confusing_elif" msgs = { "R5601": ( "Consecutive elif with differing indentation level, consider creating a function to separate the inner" " elif", "confusing-consecutive-elif", "Used when an elif statement follows right after an indented block which itself ends with if or elif. " "It may not be ovious if the elif statement was willingly or mistakenly unindented. " "Extracting the indented if statement into a separate function might avoid confusion and prevent " "errors.", ) } @only_required_for_messages("confusing-consecutive-elif") def visit_if(self, node: nodes.If) -> None: body_ends_with_if = isinstance( node.body[-1], nodes.If ) and self._has_no_else_clause(node.body[-1]) if node.has_elif_block() and body_ends_with_if: self.add_message("confusing-consecutive-elif", node=node.orelse[0]) @staticmethod def _has_no_else_clause(node: nodes.If) -> bool: orelse = node.orelse while orelse and isinstance(orelse[0], nodes.If): orelse = orelse[0].orelse if not orelse or isinstance(orelse[0], nodes.If): return True return False def register(linter: PyLinter) -> None: linter.register_checker(ConfusingConsecutiveElifChecker(linter))