intellij-lsp VS eglot

The alternatives I see are: Comrade plugin and IntelliJ LSP. But I was never able to give this a go yet.

I haven't tested your extension, but I'm always glad to see these kinds of contributions to the ecosystem. If you want to increase the utility of your code, you might consider distributing your extension and your language server separately. Then users of other editors can use your server as well (e.g. Neovim, Emacs, JetBrains IDEs). Many extension developers decouple language server and VSCode extension. See for example the repositories for the Kotlin extension and server and the Java extension and server.

IDEA has a language-server plugin: https://github.com/gtache/intellij-lsp

Recently I stumbled upon this issue:

https://github.com/joaotavora/eglot/discussions/1127

I don't know enough about emacs and LSP to see the full picture, but it seems that both eglot's and corfu's maintainers, assumably very competent programmers, can't find a solution for this.

I only skimmed the thread. My understanding is that LSP dumps a long list of completion candidates at once and they can't decide a cache strategy that works well with existing code...?

It could be. There are unfixed issues with eglot and corfu, and sadly not a lot of willingness to investigate.

Eglot errors when I add new Python code blocks. The error disappears when I reconnect the language server, but the same happens again when I add a new code block. My "workaround" now is that before I start working on the .qmd file, I just add a bunch of Python code blocks (for which I also have a function) and then reconnect the language server again. This way I can start working for a while until I need to add more code blocks again.

This discussion has helped with some performance issues: https://github.com/joaotavora/eglot/discussions/993.

I guess eglot doesn't support it yet: https://github.com/joaotavora/eglot/pull/839

This is not by pure chance, João is the developer of the Eglot LSP client and the breadcrumbs from LSP-mode had been requested as a feature, but as far as I remember João thought rightfully that this could be an independent package, see https://github.com/joaotavora/eglot/discussions/988

A substantial section of the community is using corfu instead of company, but I wouldn't say company is out of date by any means. In emacs 29 eglot will be a built in, which might act as a replacement for lsp-mode depending on what functionality you need.

I am currently running emacs 29 (built from emacs-29 branch) which – according to https://github.com/joaotavora/eglot – should contain the latest eglot.

Yep. You can use flymake or flycheck for that in combination with eglot or lsp-mode.

See https://github.com/joaotavora/eglot#diagnostics

(I have reported this (that is, ElDoc missing docs for callable things at point, when Eglot is enabled) as an issue recently: First on GitHub-discussions https://github.com/joaotavora/eglot/discussions/1200, then on Debbugs https://debbugs.gnu.org/cgi/bugreport.cgi?bug=62687. But the threads are very long, so I don't recommend reading them.)