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Editing: for_any_all.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 for loops that only check for a condition.""" from __future__ import annotations from typing import TYPE_CHECKING from astroid import nodes from pylint.checkers import BaseChecker from pylint.checkers.utils import ( assigned_bool, only_required_for_messages, returns_bool, ) from pylint.interfaces import HIGH if TYPE_CHECKING: from pylint.lint.pylinter import PyLinter class ConsiderUsingAnyOrAllChecker(BaseChecker): name = "consider-using-any-or-all" msgs = { "C0501": ( "`for` loop could be `%s`", "consider-using-any-or-all", "A for loop that checks for a condition and return a bool can be replaced with any or all.", ) } @only_required_for_messages("consider-using-any-or-all") def visit_for(self, node: nodes.For) -> None: if len(node.body) != 1: # Only If node with no Else return if not isinstance(node.body[0], nodes.If): return if_children = list(node.body[0].get_children()) if any(isinstance(child, nodes.If) for child in if_children): # an if node within the if-children indicates an elif clause, # suggesting complex logic. return node_after_loop = node.next_sibling() if self._assigned_reassigned_returned(node, if_children, node_after_loop): final_return_bool = node_after_loop.value.name suggested_string = self._build_suggested_string(node, final_return_bool) self.add_message( "consider-using-any-or-all", node=node, args=suggested_string, confidence=HIGH, ) return if self._if_statement_returns_bool(if_children, node_after_loop): final_return_bool = node_after_loop.value.value suggested_string = self._build_suggested_string(node, final_return_bool) self.add_message( "consider-using-any-or-all", node=node, args=suggested_string, confidence=HIGH, ) return @staticmethod def _if_statement_returns_bool( if_children: list[nodes.NodeNG], node_after_loop: nodes.NodeNG ) -> bool: """Detect for-loop, if-statement, return pattern: Ex: def any_uneven(items): for item in items: if not item % 2 == 0: return True return False """ if not len(if_children) == 2: # The If node has only a comparison and return return False if not returns_bool(if_children[1]): return False # Check for terminating boolean return right after the loop return returns_bool(node_after_loop) @staticmethod def _assigned_reassigned_returned( node: nodes.For, if_children: list[nodes.NodeNG], node_after_loop: nodes.NodeNG ) -> bool: """Detect boolean-assign, for-loop, re-assign, return pattern: Ex: def check_lines(lines, max_chars): long_line = False for line in lines: if len(line) > max_chars: long_line = True # no elif / else statement return long_line """ node_before_loop = node.previous_sibling() if not assigned_bool(node_before_loop): # node before loop isn't assigning to boolean return False assign_children = [x for x in if_children if isinstance(x, nodes.Assign)] if not assign_children: # if-nodes inside loop aren't assignments return False # We only care for the first assign node of the if-children. Otherwise it breaks the pattern. first_target = assign_children[0].targets[0] target_before_loop = node_before_loop.targets[0] if not ( isinstance(first_target, nodes.AssignName) and isinstance(target_before_loop, nodes.AssignName) ): return False node_before_loop_name = node_before_loop.targets[0].name return ( first_target.name == node_before_loop_name and isinstance(node_after_loop, nodes.Return) and isinstance(node_after_loop.value, nodes.Name) and node_after_loop.value.name == node_before_loop_name ) @staticmethod def _build_suggested_string(node: nodes.For, final_return_bool: bool) -> str: """When a nodes.For node can be rewritten as an any/all statement, return a suggestion for that statement. 'final_return_bool' is the boolean literal returned after the for loop if all conditions fail. """ loop_var = node.target.as_string() loop_iter = node.iter.as_string() test_node = next(node.body[0].get_children()) if isinstance(test_node, nodes.UnaryOp) and test_node.op == "not": # The condition is negated. Advance the node to the operand and modify the suggestion test_node = test_node.operand suggested_function = "all" if final_return_bool else "not all" else: suggested_function = "not any" if final_return_bool else "any" test = test_node.as_string() return f"{suggested_function}({test} for {loop_var} in {loop_iter})" def register(linter: PyLinter) -> None: linter.register_checker(ConsiderUsingAnyOrAllChecker(linter))
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