W605 fix is unsafe

[Jinzhe Zeng]

Before fix:

print("\
test\.")

The original output:

$ python test_w605.py
test\.

Fix it:

$ ruff check test_w605.py --select W605 --fix --isolated
Found 1 error (1 fixed, 0 remaining).

The file becomes

print(r"\
test\.") 

Run it again:

$ python test_w605.py 
\
test\.

The output changes. So the fix is unsafe.

[Charlie Marsh]

I'm sorry, I don't understand the difference between the two snippets. I something being obscured by GitHub's formatting?

[Jinzhe Zeng]

Sorry I made a mistake, I fixed it.

In short, the first backslash (\) gives different outputs with the raw string and the regular string.

>>> "\
... "
''
>>> r"\
... "
'\\\n'

[Zanie Blue]

Is this an unsafe fix or is this just a bug that we should fix?

[Jinzhe Zeng]

Is this an unsafe fix or is this just a bug that we should fix?

I think it is a bug that should be fixed, and due to this bug, the current fix is unsafe.

[Charlie Marsh]

Let's fix the bug rather than changing the safety.