ruff does not send linting hints via the lsp server to vim-ale

[Onturenio]

Hi, I have a doubt that is rather a configuration issue. I do not think it is a bug, but I'm puzzled and I was wondering if anyone could help to debug the issue.

In a nutshell, the problem is as the title says. I have installed python-lsp-server together with python-lsp-ruff. I'm using as client the ALE plugin of Vim (I do not think this is itself important, but I say it to give the complete background).

Now, I setup ALE to get linting hits from pylsp

let g:ale_linters = {'python': ['pylsp']}
let g:ale_fixers = {'python': ['ruff_format']}a

I have also disabled anything but ruff for linting:

let g:ale_python_pylsp_config = {
\   'pylsp': {
\       'plugins': {
\           'ruff': { 'enabled': v:true },
\           "flake8": { "enabled": v:false },
\           "pycodestyle": { "enabled": v:false },
\           "pyflakes": { "enabled": v:false },
\           }
\       }
\}

I'm running Vim from an environment where both pylsp and ruff are reachable.

> pip list | grep -e lsp -e ruff
python-lsp-jsonrpc    1.1.2
python-lsp-ruff       1.2.0
python-lsp-server     1.12.2
ruff                  0.14.1

However, when I type "wrong python code", I get no linting whatsoever. The output of ALEInfo seems correct:

(executable check - success) pylsp
(started) ['/usr/bin/bash', '-c', 'cd ''/etc/ecmwf/nfs/dh1_home_b/sp4e/gSR      EPS'' && ''pylsp''']

To make things even more confusing, I have been able to setup this exactly equal in my laptop and it does work as expected, with pylsp serving correct linting hints from running ruff in the background.

What could be causing the miscommunication in this machine? How can I test intermediate steps to assert what is the missing link?

EDIT: there are a few more pieces of information that might be relevant but I'm not sure how to interpret:

• if I select ruff as linting (besides pylsp), I get correct hints from ruff. This is,

let g:ale_linters = {'python': ['pylsp', 'ruff']}

• the other LSP features such as going to definitions or finding references, do work
• I'm pretty sure that fixing the code did work yesterday, but I'm right now making tests and now it does NOT work. I'm not sure why or what exactly I have changed

Thank you!

PS: I apologise if this is not the right forum to ask. I believe python-lsp-server is the core issue, but perhaps ALE or even ruff is the problem. If you think this might be the case, I'm sorry and I'll move my question somewhere else.