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from dataclasses import dataclass
from mypy.nodes import CallExpr, MemberExpr, NameExpr, StrExpr, Var
from refurb.error import Error
@dataclass
class ErrorInfo(Error):
"""
In some situations the `.lstrip()`, `.rstrip()` and `.strip()` string
methods can be written more succinctly: `strip()` is the same thing as
calling both `lstrip()` and `rstrip()` together, and all the strip
functions take an iterable argument of the characters to strip, meaning
you don't need to call strip methods multiple times with different
arguments, you can just concatenate them and call it once.
Bad:
```
name = input().lstrip().rstrip()
num = " -123".lstrip(" ").lstrip("-")
```
Good:
```
name = input().strip()
num = " -123".lstrip(" -")
```
"""
name = "simplify-strip"
code = 159
categories = ("readability", "string")
STRIP_FUNCS = ("lstrip", "rstrip", "strip")
def check(node: CallExpr, errors: list[Error]) -> None:
match node:
case CallExpr(
callee=MemberExpr(
expr=CallExpr(
callee=MemberExpr(expr=expr, name=lhs_func),
args=lhs_args,
),
name=rhs_func,
),
args=rhs_args,
) if rhs_func in STRIP_FUNCS and lhs_func in STRIP_FUNCS:
match expr:
case StrExpr():
pass
case NameExpr(node=Var(type=ty)) if str(ty) == "builtins.str":
pass
case _:
return
exprs: list[str]
match lhs_args, rhs_args:
case [], []:
lhs_arg = rhs_arg = ""
if lhs_func == rhs_func:
exprs = [f"{lhs_func}()"]
else:
exprs = ["strip()"]
case (
[StrExpr(value=lhs_arg)],
[StrExpr(value=rhs_arg)],
):
if lhs_func == rhs_func:
combined = "".join(sorted(set(lhs_arg + rhs_arg)))
exprs = [f"{lhs_func}({combined!r})"]
elif lhs_arg == rhs_arg:
exprs = [f"strip({lhs_arg!r})"]
else:
return
lhs_arg = repr(lhs_arg)
rhs_arg = repr(rhs_arg)
case _:
return
lhs = f"{lhs_func}({lhs_arg})"
rhs = f"{rhs_func}({rhs_arg})"
new = f"x.{'.'.join(exprs)}"
errors.append(ErrorInfo.from_node(node, f"Replace `x.{lhs}.{rhs}` with `{new}`"))
|
