Invalid fix for UP025 when implicitly concatenated with f-string

[dhruvmanila]

Note that this is unrelated to the new f-string changes.

If a unicode string is implicitly concatenated with a f-string, then the fix removes the first character of the string instead of the prefix:

u"foo" f"{bar}"

The fix:

$ pipx run "ruff==0.0.291" check --select=UP  ~/playground/ruff/fstring.py --ecosystem-ci
/Users/dhruv/playground/ruff/fstring.py:1:3: UP025 [*] Remove unicode literals from strings
ℹ Fix
1   |-u"foo" f"{bar}"
  1 |+u"oo" f"{bar}"

Found 1 error.
[*] 1 potentially fixable with the --fix option.

This is because the "foo" string is part of the outer f-string expression and the range of the string constant is within the quotes.

[harupy]

@dhruvmanila Can I work on this?

[dhruvmanila]

I would recommend to wait for this a bit as we could change the AST representation for an implicit string concatenation node which then would make this easier to solve.

[harupy]

@dhruvmanila Sounds good!