is there a way to let ruff check --watch honor the --format=json option?

[haolian9]

hi folks! I found that ruff check --format=json --watch foo.py keep outputing text format messages rather than the asked format, json. do you think it's a valid use-case? also since the output json contains \n, would it be a problem in this use-case?

[charliermarsh]

It's not supported right now but I suppose we could support it. What's the use-case? Do you just prefer to have JSON output in your terminal? Or are you trying to pipe to another tool?

[haolian9]

hi, i was planning to get ruff and neovim married: a) spawn a ruff process along the side of neovim, b) keep reading from its stdout/stderr, c) parse the output as diagnostics, d) feed into nvim's diagnostic.

the things i concerned about in the above plan:

• cheap&fast: the ruff binary is about 14M on my linux machine, so a long-lived process --watch is good to have, yet I find no way to add new file to ruff's watching list.
• easy parsing: there is &errorformat in nvim, but it's so complicated that i dont want to use it. and json is prefered over plain text which is structual, though it has a overhead on (de)serializing.

there is a ruff-ls already, it requires python and several packages to run, i personally dont like that; but it made me want a C API from ruff, so that I can use it with luajit's FFI.

i'm not sure if what would the plan be resulted as: a new nvim plugin to use ruff or integrating it into nvim-null-ls or efm-server or something else.

it's just a random thought, thank you for taking time on it!