Logging which files were changed when running `ruff format .` ?

[thvasilo]

Hi team, thanks for the great tool.

One of the small features I appreciated with black is that it would list which files where changed when I ran the command, is it possible to have that with ruff as well?

[T-256]

There are already --check and --diff options for formatter:

> ruff format . --check
Would reformat: demo.py
Would reformat: wgpy.py
2 files would be reformatted

if you need unified command for both check and modify files in one command, then we could consider an option to do it:

> ruff format . --check --force-modify
Would reformat: demo.py
Would reformat: wgpy.py
2 files reformatted

[MichaReiser]

One of the small features I appreciated with black is that it would list which files where changed when I ran the command, is it possible to have that with ruff as well?

May I ask what you use the printed file names? Is it to better understand what the command changed? Would you expect ruff check --fix (linter) to show the names of fixed files too?

The reasons that I'm aware why we aren't printing file names today are: a) printing many names to the console may require more time than ruff linting all your files and b) can be very verbose if many files were changed.

[thvasilo]

Is it to better understand what the command changed ?

Yes that would be it. At least for smaller projects usually there's only a few files changed for each commit, with the black pre-commit hook I could see which files were changed, so if there's an option to do it with ruff I'd use it.

ruff format . --check --force-modify

Yup something like that would work.

[MichaReiser]

I must admit I never used pre-commit myself so happy to learn with you. Can you use ruff format without the check inside of your pre-commit. The step should fail if there are any modified files according to @charliermarsh's comment. Any chance that the pre-commit hook lists the changed files in the error message?

Another option that is supported today is to use --diff, but it not only prints the file name but also the diff for each file. Not sure if that's too noisy.

[Dev-iL]

May I ask what you use the printed file names?

I can share my own reasoning why I need to know which files were changed: when I have commits which modify multiple files and files have some staged as well as unstaged changes, I have no idea which parts of which files I need to stage to make ruff happy.

Therefore, if there was an "auto-stage fixes" option, I wouldn't need to know which files were changed.

[markbaird]

As another user switching over from black I would like to echo the request to show the list of files that were modified. If I commit 10 files, and I all I get is this message from Ruff:

 - files were modified by this hook 
Found 1 error (1 fixed, 0 remaining).

It is a bit disconcerting not having any indication of which file was modified.

The reasons that I'm aware why we aren't printing file names today are: a) printing many names to the console may require more time than ruff linting all your files and b) can be very verbose if many files were changed.

@MichaReiser I think it's reasonable that this should be a configuration option that is disabled by default, so people would have to opt-in to the extra output if they accept the performance hit and the extra noise. I tried using --verbose but this is way too noisy to be useful. I think something like a --info log level would be appropriate.