Summary
With preview enabled, the fix for PERF401 can duplicate comments if they are inside an empty tuple inside the if test. playground
PS D:\python_projects> Get-Content issue.py
original = list(range(10000))
filtered = []
for i in original:
if (
# comment
):
filtered.append(i)PS D:\python_projects> uvx ruff check issue.py --select PERF --preview
issue.py:7:9: PERF401 Use a list comprehension to create a transformed list
|
5 | # comment
6 | ):
7 | filtered.append(i)
| ^^^^^^^^^^^^^^^^^^ PERF401
|
= help: Replace for loop with list comprehension
Found 1 error.
No fixes available (1 hidden fix can be enabled with the `--unsafe-fixes` option).
PS D:\python_projects> uvx ruff check issue.py --select PERF --preview --unsafe-fixes --fix --diff
--- issue.py
+++ issue.py
@@ -1,7 +1,5 @@
original = list(range(10000))
-filtered = []
-for i in original:
- if (
+# comment
+filtered = [i for i in original if (
# comment
- ):
- filtered.append(i)
+ )]
Would fix 1 error.This also applies to PERF403 playground
Version
ruff 0.12.0 (87f0feb 2025-06-17) + playground
Summary
With preview enabled, the fix for
PERF401can duplicate comments if they are inside an empty tuple inside theiftest. playgroundThis also applies to
PERF403playgroundVersion
ruff 0.12.0 (87f0feb 2025-06-17) + playground