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from dataclasses import dataclass
from mypy.nodes import (
Block,
CallExpr,
ExpressionStmt,
MemberExpr,
MypyFile,
NameExpr,
Statement,
Var,
)
from refurb.checks.common import check_block_like
from refurb.error import Error
@dataclass
class ErrorInfo(Error):
"""
When appending multiple values to a list, you can use the `.extend()`
method to add an iterable to the end of an existing list. This way, you
don't have to call `.append()` on every element:
Bad:
```
nums = [1, 2, 3]
nums.append(4)
nums.append(5)
nums.append(6)
```
Good:
```
nums = [1, 2, 3]
nums.extend((4, 5, 6))
```
"""
name = "use-list-extend"
code = 113
msg: str = "Use `x.extend(...)` instead of repeatedly calling `x.append()`"
categories = ("list",)
@dataclass
class Last:
name: str = ""
line: int = 0
column: int = 0
did_error: bool = False
def check(node: Block | MypyFile, errors: list[Error]) -> None:
check_block_like(check_stmts, node, errors)
def check_stmts(stmts: list[Statement], errors: list[Error]) -> None:
last = Last()
for stmt in stmts:
match stmt:
case ExpressionStmt(
expr=CallExpr(
callee=MemberExpr(
expr=NameExpr(name=name, node=Var(type=ty)),
name="append",
),
)
) if str(ty).startswith("builtins.list["):
if not last.did_error and name == last.name:
errors.append(ErrorInfo(last.line, last.column))
last.did_error = True
last.name = name
last.line = stmt.line
last.column = stmt.column
case _:
last = Last()
|
