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from dataclasses import dataclass
from mypy.nodes import (
ArgKind,
Argument,
Block,
CallExpr,
DictExpr,
Expression,
LambdaExpr,
ListExpr,
NameExpr,
RefExpr,
ReturnStmt,
TupleExpr,
)
from refurb.checks.common import stringify
from refurb.error import Error
@dataclass
class ErrorInfo(Error):
"""
Don't use a lambda if it is just forwarding its arguments to a
function verbatim:
Bad:
```
predicate = lambda x: bool(x)
some_func(lambda x, y: print(x, y))
```
Good:
```
predicate = bool
some_func(print)
```
"""
name = "use-func-name"
code = 111
categories = ("readability",)
def get_lambda_arg_names(args: list[Argument]) -> list[str]:
return [arg.variable.name for arg in args]
def get_func_arg_names(args: list[Expression]) -> list[str | None]:
return [arg.name if isinstance(arg, NameExpr) else None for arg in args]
def check(node: LambdaExpr, errors: list[Error]) -> None:
match node:
case LambdaExpr(
arguments=lambda_args,
body=Block(
body=[
ReturnStmt(expr=CallExpr(callee=RefExpr() as ref) as func),
]
),
) if (
get_lambda_arg_names(lambda_args) == get_func_arg_names(func.args)
and all(kind == ArgKind.ARG_POS for kind in func.arg_kinds)
):
func_name = stringify(ref)
arg_names = get_lambda_arg_names(lambda_args)
arg_names = ", ".join(arg_names) if arg_names else ""
_lambda = f"lambda {arg_names}" if arg_names else "lambda"
errors.append(
ErrorInfo.from_node(
node,
f"Replace `{_lambda}: {func_name}({arg_names})` with `{func_name}`", # noqa: E501
)
)
case LambdaExpr(
arguments=[],
body=Block(
body=[
ReturnStmt(
expr=ListExpr(items=[]) | DictExpr(items=[]) | TupleExpr(items=[]) as expr,
)
],
),
):
if isinstance(expr, ListExpr):
old = "[]"
new = "list"
elif isinstance(expr, DictExpr):
old = "{}"
new = "dict"
else:
old = "()"
new = "tuple"
errors.append(
ErrorInfo.from_node(
node,
f"Replace `lambda: {old}` with `{new}`",
)
)
|
