Rendering chars lags behind typing when open large rust repository

[rafaeljacov]

I cloned the uv repo and after rust-analyzer loaded, typing characters shows significant delay in rendering. I tried this with neovim and doom emacs, and rendering characters does not show lag when typing

[RoloEdits]

Can you provide a more concrete chain of steps? What file? Was it all files? What version of helix? What OS? And in the future, please use the issue template, if at all possible. It may seem annoying, but it really does help get past the initial queries 😄.

[rafaeljacov]

@RoloEdits ok I tried it again and it was strange. It only lags on a specific file. which is uv/crates/uv-cli/lib.rs

I'm using helix 25.07.1 inside NixOs unstable and am not using any config for helix

[RoloEdits]

Thanks! I was able to reproduce:

Seems like its the tree-sitter-rust parsing. This can be confirmed by switching the language to text: :lang text. Given the circumstances, my guess is that its related to parsing the attribute macros. Its the only thing in great number, outside of the norm. I went through an commented out sections, and as I was doing so, the lag progressively improved, rather than one thing being commented out and instantly recovering the performance loss. Grammar version is up to latest master already, so have to wait till this is fixed.

I remember talk about better incremental/chunking parsing or asynchronous parsing, but cant find the issue this would have been mentioned. But this would improve the situation when actually interacting with the document.

Some other related issues: #3072 #4139 #4513 #14945

[rafaeljacov]

If it is a tree-sitter-rust problem though how is it that neovim opening the same file does not lag?

[RoloEdits]

Probably: neovim/neovim#31631 neovim/neovim#32000 neovim/neovim#31827 neovim/neovim#24647 etc.

zed use the same grammar. If you tried it, it might also not show, as I'm pretty sure they implement highlighting in a way that it wont block the UI when its re-parsing the file.

@the-mikedavis might know more on this.