Respect `--output-format` with `--watch`

[sathishvj]

Question

The ruff linter for python in watch mode does not show code details and position of error.

If I run "ruff check .", if there is a code error, it shows me the code where the issue is.

If I run "ruff check --watch .", it does not show me code details.

Version

No response

[MeGaGiGaGon]

Please give more information on the ruff version you are using (run ruff version), the files/folder you are trying to watch, and the configuration you are using. Testing locally it works fine on ruff 0.12.4 (ee2759b 2025-07-17) (running uvx ruff check --watch . --isolated), so more details are needed. Info about your operating system may also be useful.

[sathishvj]

ruff 0.12.4
MacOs Sequoia 15.5
BASH_VERSION = 5.2.37(1)-release
I don't have a ruff.toml locally

I installed ruff with homebrew. I also ran it as you did with "uvx ruff".
The output is still minimal.

The folder I am watching is the current folder with a bunch of python files.

[MeGaGiGaGon]

👍 . Sadly I can't test it since I'm on windows, but hopefully someone else with a mac can. Can you send the output of uvx ruff check --watch . --isolated -v, since there might be something useful there?

[sathishvj]

[11:01:51 AM] Starting linter in watch mode...
[2025-07-25][11:01:51][ruff_workspace::resolver][DEBUG] Included path via include: "/main.py"
[2025-07-25][11:01:51][ruff::diagnostics][DEBUG] Checking: //main.py
/main.py:344:3: SyntaxError: Expected an expression

There are lots of other files that are listed too, but I believe this would be the relevant logs.

Thank you.

[MeGaGiGaGon]

Ah I see, I misunderstood the problem. I assumed it was that the file paths weren't appearing, instead of wanting the full output format.

As far as I'm aware, currently --watch only supports that singular output format, and trying to set other ones with --output-format has no effect.

[sathishvj]

Oh. My apologies for not being clearer in the original issue message - I shouldn't have wasted your time like that and I shall do better next time. Yet, thank you for your responses.

For others here, my workaround is to use a file watcher like fswatch/watchman/watchexec to watch for file changes and then execute ruff.

To the ruff team, it would be good to have a flag to enable detailed output with code snippet even in --watch mode, like so:

main.py:344:3: SyntaxError: Expected an expression
342 |     app.run(host='0.0.0.0', port=int(os.environ.get('PORT', 8080)), debug=True)
343 |
344 | x-
    |   ^

[MichaReiser]

@ntBre another diagnostic related improvement

[ntBre]

@sathishvj I'll reopen this if it's okay with you. I think it makes sense to support more output formats in watch mode as you said.