| 123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172737475767778798081828384858687888990919293949596979899100101102103104105106107108109110111112113114115116117118119120121122123124125126127128129130131132133134135136137138139140141142143144145146147148149150151152153154155156157158159160161162 |
- # Licensed under the GPL: https://www.gnu.org/licenses/old-licenses/gpl-2.0.html
- # For details: https://github.com/pylint-dev/pylint/blob/main/LICENSE
- # Copyright (c) https://github.com/pylint-dev/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))
|