I'm using pylsp (python-language-server). My reason being a process of elimination. I also use mypy for type-checking, so even without considering the danger of allowing MS to entrench itself into my tooling, it didn't make much sense to use a tool built around pyright.
The ruff-lsp seems to only do the things that ruff is good at: linting, code formatting, auto-fix of certain issues, and I wanted more.
Since I saw that pylsp uses Jedi under the hood, and offered a mypy plugin, I felt that pylsp offer a superset of the features that the Jedi LSP has. In the end I'm happy with pylsp, and never tried Jedi LSP.
However: with the mypy plugin for pylsp, the memory usage kept growing to ridiculous amounts and getting killed, so I ended up disabling it. I had a look in their bug tracker Instead, I'm using flymake that triggers mypy on save, and that seems to work well. (I have a few changes on top of com4/flymake-mypy.el, because it leaves behind plenty of temporary files.)
That offers me:
- jump to definition (using Jedi under the hood)
- rename symbol (and then Jedi goes and rename uses of that symbol)
- smart completion (eg. offers only variables in scope, or after a
.
only the instance members, etc.) - short documentation on hover
- squiggly lines for errors found by flake8 or mypy
- and a few more that I don't really notice
One thing I struggled with: where do you install the LSP? Using pipx for a user installation, or in a per-project venv? I did the latter, which works for me because I work on a small number of projects. That also means that mypy finds all the relevant third-party libraries in that venv. I wrote a bit of elisp that allow emacs to find the right mypy binary to check code.
On Linux, by default they're not. getcpu(2) says: