Improving Eglot performance

Yesterday I started to rewrite the mataroa-cli tool for the millionth time. This time I chose Rust to do it for three reasons:

1. I like its type system¹, even though I don’t really like the borrow checker
2. I can statically compile to multiple architectures, nice for a CLI tool
3. The toolchain is really good, the LSP and Cargo are a blessing

While writing the initial portion of the code, I noticed a mild input lag every time I added a new crate. Weird, I’m not writing a lot of code and it’s not my computer that is lagging. After a few minutes searching for the root cause, I discovered that Eglot prettifies the LSP’s JSON RPC output. You can read more on the GNU Emacs bug report #65760.

The solution is quite simple:

(use-package eglot
  :config
  (advice-add 'jsonrpc--log-event :override #'ignore))