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from dataclasses import dataclass
from mypy.nodes import DelStmt, IndexExpr, NameExpr, SliceExpr, Var
from refurb.error import Error
@dataclass
class ErrorInfo(Error):
"""
The `del` statement is commonly used for popping single elements from dicts
and lists, though a slice can be used to remove a range of elements
instead. When removing all elements via a slice, use the faster and more
succinct `.clear()` method instead.
Bad:
```
names = {"key": "value"}
nums = [1, 2, 3]
del names[:]
del nums[:]
```
Good:
```
names = {"key": "value"}
nums = [1, 2, 3]
names.clear()
nums.clear()
```
"""
name = "no-del"
code = 131
categories = ("builtin", "readability")
msg: str = "Replace `del x[:]` with `x.clear()`"
def check(node: DelStmt, errors: list[Error]) -> None:
match node:
case DelStmt(expr=IndexExpr(base=NameExpr(node=Var(type=ty)), index=index)) if str(
ty
).startswith(("builtins.dict[", "builtins.list[")):
match index:
case SliceExpr(begin_index=None, end_index=None):
errors.append(ErrorInfo.from_node(node))
|
