F821 Undefined name code position incorrect in f-strings

[nikolaik]

When trying to ignore F821 in some cases, like importing variables using star imports, I can't when the variable is used in an f-string. The line and column position seems to be off. Is that used to match the noqa comments?

# a.py:
some_string = 'to increase the line count'

A = f'{B}'  # noqa: F821
A = B  # noqa: F821

$ ruff a.py
a.py:1:2: F821 Undefined name `B`

Found 1 error(s).

[charliermarsh]

Yeah this looks like an issue in the parser -- the positions on the sub-expressions seem to be relative to the parent f-string. Thanks.

[charliermarsh]

(This is a blocker for 0.1.0.)

[charliermarsh]

#244 modifies the reporter to use the location of the start of the f-string. It's probably the best we can do without fixing this in the parse itself (which is a bit more involved). With this change, it'll at least be clear where you should put the noqa, and the location is a lot more reasonable (at the line on which the f-string starts, instead of at the top of the file).

[nikolaik]

Thank you @charliermarsh ! This works and is the last piece missing to allow us to use ruff one of our projects ❤️

[charliermarsh]

Np! If you hit any issues, don't hesitate to reach out!