bug#66669: 30.0.50; [EGLOT] Emacs freezes when server sends a ton of progress notifications

[Yuan Fu]

X-Debbugs-CC: joaotavora@gmail.com

I use rust’s language server (rust-analyzer) with eglot. And whenever I turn 
eglot on for a project, Emacs freezes for a good 30 seconds, busy updating the 
eglot progress indicator, before I can do anything. I think the reason is that 
the rust language server sends a ton of progress notifications, which 
completely blocks Emacs before it’s done.

Setting eglot-report-progress to nil doesn’t help me, presumably because eglot 
still needs to process the notifications.

I wonder if we can only take a sample of the progress notifications, and ignore 
the majority, so that Emacs is free to respond to user input?

In the same vain, I wonder if we can instruct Emacs to filter out some messages 
from the server at process filter level and never call into lisp for these 
messages, such that some particularly noisy servers (eg, 
typescript-language-server) won’t slow down Emacs a perceivable amount?

I attached the events log during the start up of eglot in my rust project. As 
you can see, it sends a dozen notifications per second.

Yuan

indexing-events.log
Description: Binary data