/opt/imh-python/lib/python3.9/site-packages/pylint/checkers
Edit: /opt/imh-python/lib/python3.9/site-packages/pylint/checkers/nested_min_max.py (5583B)
# 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 nested min/max functions."""
from __future__ import annotations
import copy
from typing import TYPE_CHECKING
from astroid import nodes, objects
from astroid.const import Context
from pylint.checkers import BaseChecker
from pylint.checkers.utils import only_required_for_messages, safe_infer
from pylint.interfaces import INFERENCE
if TYPE_CHECKING:
from pylint.lint import PyLinter
DICT_TYPES = (
objects.DictValues,
objects.DictKeys,
objects.DictItems,
nodes.node_classes.Dict,
)
class NestedMinMaxChecker(BaseChecker):
"""Multiple nested min/max calls on the same line will raise multiple messages.
This behaviour is intended as it would slow down the checker to check
for nested call with minimal benefits.
"""
FUNC_NAMES = ("builtins.min", "builtins.max")
name = "nested_min_max"
msgs = {
"W3301": (
"Do not use nested call of '%s'; it's possible to do '%s' instead",
"nested-min-max",
"Nested calls ``min(1, min(2, 3))`` can be rewritten as ``min(1, 2, 3)``.",
)
}
@classmethod
def is_min_max_call(cls, node: nodes.NodeNG) -> bool:
if not isinstance(node, nodes.Call):
return False
inferred = safe_infer(node.func)
return (
isinstance(inferred, nodes.FunctionDef)
and inferred.qname() in cls.FUNC_NAMES
)
@classmethod
def get_redundant_calls(cls, node: nodes.Call) -> list[nodes.Call]:
return [
arg
for arg in node.args
if (
cls.is_min_max_call(arg)
and arg.func.name == node.func.name
# Nesting is useful for finding the maximum in a matrix.
# Allow: max(max([[1, 2, 3], [4, 5, 6]]))
# Meaning, redundant call only if parent max call has more than 1 arg.
and len(arg.parent.args) > 1
)
]
@only_required_for_messages("nested-min-max")
def visit_call(self, node: nodes.Call) -> None:
if not self.is_min_max_call(node):
return
redundant_calls = self.get_redundant_calls(node)
if not redundant_calls:
return
fixed_node = copy.copy(node)
while len(redundant_calls) > 0:
for i, arg in enumerate(fixed_node.args):
# Exclude any calls with generator expressions as there is no
# clear better suggestion for them.
if isinstance(arg, nodes.Call) and any(
isinstance(a, nodes.GeneratorExp) for a in arg.args
):
return
if arg in redundant_calls:
fixed_node.args = (
fixed_node.args[:i] + arg.args + fixed_node.args[i + 1 :]
)
break
redundant_calls = self.get_redundant_calls(fixed_node)
for idx, arg in enumerate(fixed_node.args):
if not isinstance(arg, nodes.Const):
if self._is_splattable_expression(arg):
splat_node = nodes.Starred(
ctx=Context.Load,
lineno=arg.lineno,
col_offset=0,
parent=nodes.NodeNG(
lineno=None,
col_offset=None,
end_lineno=None,
end_col_offset=None,
parent=None,
),
end_lineno=0,
end_col_offset=0,
)
splat_node.value = arg
fixed_node.args = (
fixed_node.args[:idx]
+ [splat_node]
+ fixed_node.args[idx + 1 : idx]
)
self.add_message(
"nested-min-max",
node=node,
args=(node.func.name, fixed_node.as_string()),
confidence=INFERENCE,
)
def _is_splattable_expression(self, arg: nodes.NodeNG) -> bool:
"""Returns true if expression under min/max could be converted to splat
expression.
"""
# Support sequence addition (operator __add__)
if isinstance(arg, nodes.BinOp) and arg.op == "+":
return self._is_splattable_expression(
arg.left
) and self._is_splattable_expression(arg.right)
# Support dict merge (operator __or__)
if isinstance(arg, nodes.BinOp) and arg.op == "|":
return self._is_splattable_expression(
arg.left
) and self._is_splattable_expression(arg.right)
inferred = safe_infer(arg)
if inferred and inferred.pytype() in {"builtins.list", "builtins.tuple"}:
return True
if isinstance(
inferred or arg,
(
nodes.List,
nodes.Tuple,
nodes.Set,
nodes.ListComp,
nodes.DictComp,
*DICT_TYPES,
),
):
return True
return False
def register(linter: PyLinter) -> None:
linter.register_checker(NestedMinMaxChecker(linter))