[Help]: Update(?) Breaks pylsp?: ModuleNotFoundError: No module named 'pylsp'

[ghost-in-the-zsh]

Hi,

I've been using nvim¹ for several months, including pylsp. Everything has been working fine, but over the weekend, I noticed that opening Python files how results in the LSP crashing with the following error message:

From :LspLog

[START][2024-07-01 17:32:01] LSP logging initiated
[ERROR][2024-07-01 17:32:01] .../vim/lsp/rpc.lua:770» "rpc"»"/home/<user>/.local/share/nvim/mason/bin/pylsp"»"stderr"» "Traceback (most recent call last):\n  File \"/home/<user>/.local/share/nvim/mason/bin/pylsp\", line 5, in <module>\n from pylsp.__main__ import main\nModuleNotFoundError: No module named 'pylsp'\n"

At most, the only thing I did last week was to run the :Mason command from inside nvim and then upgrade everything that needed upgrading (i.e. <S-u>). I don't recall seeing python-lsp-server receiving an update at the time, but I could be wrong. Other plugins seem to be working fine still, so the issue seems to be affecting pylsp only.

I'd appreciate help and/or guidance. I'm posting here first, b/c:

1. the only thing that stands out to me was using Mason to update existing plugins, and
2. I don't have steps to reproduce the problem.

For reference, I'm on Python v3.12.3 and the content of ~/.local/share/nvim/mason/bin includes:

lrwxrwxrwx 1 <user> <user> 75 May  9 17:42 pylsp -> ~/.local/share/nvim/mason/packages/python-lsp-server/venv/bin/pylsp

The sym-link is valid and does show from pylsp.__main__ import main on line 5, as noted in the error message. Checking python packages now only shows python3-lsprotocol (no more python-lsp-server?)

apt search python3-lsp\*
Sorting... Done
Full Text Search... Done
python3-lsprotocol/noble,noble 2023.0.0-1 all
  Python implementation of the Language Server Protocol

but installing it makes no difference. Searching the list of issues for pylsp and ModuleNotFoundError returns unrelated results or nothing respectively.

:checkhealth mason shows an error(?):

─────────────────────────────────────────────────────────
mason:

- ERROR No healthcheck found for "mason" plugin.

Here are the last few entries for June and today, from :MasonLog:

[INFO  Wed 26 Jun 2024 05:49:19 PM MDT] ...e/nvim/lazy/mason.nvim/lua/mason-core/installer/init.lua:245: Installation succeeded for Package(name=mypy)
[INFO  Wed 26 Jun 2024 05:49:22 PM MDT] ...e/nvim/lazy/mason.nvim/lua/mason-core/installer/init.lua:245: Installation succeeded for Package(name=ruff)
[INFO  Mon 01 Jul 2024 04:41:09 PM MDT] ...e/nvim/lazy/mason.nvim/lua/mason-core/installer/init.lua:184: Executing installer for Package(name=ruff) Package(name=ruff)
[INFO  Mon 01 Jul 2024 04:41:09 PM MDT] ...e/nvim/lazy/mason.nvim/lua/mason-core/installer/init.lua:184: Executing installer for Package(name=rust-analyzer) Package(name=rust-analyzer)
[INFO  Mon 01 Jul 2024 04:41:09 PM MDT] ...e/nvim/lazy/mason.nvim/lua/mason-core/installer/init.lua:184: Executing installer for Package(name=clang-format) Package(name=clang-format)
[INFO  Mon 01 Jul 2024 04:41:11 PM MDT] ...e/nvim/lazy/mason.nvim/lua/mason-core/installer/init.lua:245: Installation succeeded for Package(name=rust-analyzer)
[INFO  Mon 01 Jul 2024 04:41:12 PM MDT] ...e/nvim/lazy/mason.nvim/lua/mason-core/installer/init.lua:245: Installation succeeded for Package(name=clang-format)
[INFO  Mon 01 Jul 2024 04:41:13 PM MDT] ...e/nvim/lazy/mason.nvim/lua/mason-core/installer/init.lua:245: Installation succeeded for Package(name=ruff)

And what the :Mason command shows:

Thanks in advance for your help in figuring this out,
-me

Footnotes

1. Using the nvchad v2.5, to be specific. nvim itself has been at version 0.10.0 since my Ubuntu 24.04 LTS upgrade back in April. ↩

[TamaMcGlinn]

I just had this issue and fixed it by opening :Mason, selecting the (already installed) python-language-server (pylsp) and pressing 'u' for update, which seems to have reinstalled the same version.