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from dataclasses import dataclass
from mypy.nodes import AssignmentStmt, Block, CallExpr, MemberExpr, NameExpr, StrExpr, WithStmt
from refurb.error import Error
@dataclass
class ErrorInfo(Error):
"""
When you just want to save the contents of a file to a variable, using a
`with` block is a bit overkill. A simpler alternative is to use pathlib's
`read_text()` function:
Bad:
```
with open(filename) as f:
contents = f.read()
```
Good:
```
contents = Path(filename).read_text()
```
"""
name = "use-pathlib-read-text-read-bytes"
code = 101
categories = ("pathlib",)
def check(node: WithStmt, errors: list[Error]) -> None:
match node:
case WithStmt(
expr=[
CallExpr(
callee=NameExpr(name="open"),
args=args,
arg_names=arg_names,
)
],
target=[NameExpr(name=with_name)],
body=Block(
body=[
AssignmentStmt(
rvalue=CallExpr(
callee=MemberExpr(expr=NameExpr(name=read_name), name="read"),
args=[],
)
)
]
),
) if with_name == read_name:
func = "read_text"
read_text_params = ""
with_params = ""
for i, name in enumerate(arg_names[1:], start=1):
if name in {None, "mode"}:
with_params = ", ..."
match args[i]:
case StrExpr(value=mode) if "b" in mode:
func = "read_bytes"
elif name in {"encoding", "errors"}:
read_text_params = "..."
with_params = ", ..."
else:
return
errors.append(
ErrorInfo.from_node(
node,
f"Replace `with open(x{with_params}) as f: y = f.read()` with `y = Path(x).{func}({read_text_params})`", # noqa: E501
)
)
|
