94 lines
3.4 KiB
Python
94 lines
3.4 KiB
Python
|
# 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
|
||
|
|
||
|
from __future__ import annotations
|
||
|
|
||
|
from itertools import zip_longest
|
||
|
from typing import TYPE_CHECKING
|
||
|
|
||
|
from astroid import nodes
|
||
|
|
||
|
from pylint.checkers import BaseChecker
|
||
|
from pylint.interfaces import HIGH
|
||
|
|
||
|
if TYPE_CHECKING:
|
||
|
from pylint.lint import PyLinter
|
||
|
|
||
|
|
||
|
class LambdaExpressionChecker(BaseChecker):
|
||
|
"""Check for unnecessary usage of lambda expressions."""
|
||
|
|
||
|
name = "lambda-expressions"
|
||
|
msgs = {
|
||
|
"C3001": (
|
||
|
"Lambda expression assigned to a variable. "
|
||
|
'Define a function using the "def" keyword instead.',
|
||
|
"unnecessary-lambda-assignment",
|
||
|
"Used when a lambda expression is assigned to variable "
|
||
|
'rather than defining a standard function with the "def" keyword.',
|
||
|
),
|
||
|
"C3002": (
|
||
|
"Lambda expression called directly. Execute the expression inline instead.",
|
||
|
"unnecessary-direct-lambda-call",
|
||
|
"Used when a lambda expression is directly called "
|
||
|
"rather than executing its contents inline.",
|
||
|
),
|
||
|
}
|
||
|
options = ()
|
||
|
|
||
|
def visit_assign(self, node: nodes.Assign) -> None:
|
||
|
"""Check if lambda expression is assigned to a variable."""
|
||
|
if isinstance(node.targets[0], nodes.AssignName) and isinstance(
|
||
|
node.value, nodes.Lambda
|
||
|
):
|
||
|
self.add_message(
|
||
|
"unnecessary-lambda-assignment",
|
||
|
node=node.value,
|
||
|
confidence=HIGH,
|
||
|
)
|
||
|
elif isinstance(node.targets[0], nodes.Tuple) and isinstance(
|
||
|
node.value, (nodes.Tuple, nodes.List)
|
||
|
):
|
||
|
# Iterate over tuple unpacking assignment elements and
|
||
|
# see if any lambdas are assigned to a variable.
|
||
|
# N.B. We may encounter W0632 (unbalanced-tuple-unpacking)
|
||
|
# and still need to flag the lambdas that are being assigned.
|
||
|
for lhs_elem, rhs_elem in zip_longest(
|
||
|
node.targets[0].elts, node.value.elts
|
||
|
):
|
||
|
if lhs_elem is None or rhs_elem is None:
|
||
|
# unbalanced tuple unpacking. stop checking.
|
||
|
break
|
||
|
if isinstance(lhs_elem, nodes.AssignName) and isinstance(
|
||
|
rhs_elem, nodes.Lambda
|
||
|
):
|
||
|
self.add_message(
|
||
|
"unnecessary-lambda-assignment",
|
||
|
node=rhs_elem,
|
||
|
confidence=HIGH,
|
||
|
)
|
||
|
|
||
|
def visit_namedexpr(self, node: nodes.NamedExpr) -> None:
|
||
|
if isinstance(node.target, nodes.AssignName) and isinstance(
|
||
|
node.value, nodes.Lambda
|
||
|
):
|
||
|
self.add_message(
|
||
|
"unnecessary-lambda-assignment",
|
||
|
node=node.value,
|
||
|
confidence=HIGH,
|
||
|
)
|
||
|
|
||
|
def visit_call(self, node: nodes.Call) -> None:
|
||
|
"""Check if lambda expression is called directly."""
|
||
|
if isinstance(node.func, nodes.Lambda):
|
||
|
self.add_message(
|
||
|
"unnecessary-direct-lambda-call",
|
||
|
node=node,
|
||
|
confidence=HIGH,
|
||
|
)
|
||
|
|
||
|
|
||
|
def register(linter: PyLinter) -> None:
|
||
|
linter.register_checker(LambdaExpressionChecker(linter))
|