100% CPU usage and freeze in project with thousands of files

[Jeiwan]

What did you expect to happen?

Doom Emacs doesn't freeze when working with Golang.

What actually happened?

When I open a Golang project, Doom Emacs freezes consuming 100% of CPU. I don't need to do anything, just open a Golang file. This lasts very long so I eventually had to kill it because it's unusable.
This whole project was programmed in Doom Emacs and everything had been ok until I updated Doom and Emacs a couple of days ago (I had an old version of Doom, maybe more than 6 months old).

This is a fresh install: Emacs 27.2, latest Doom. The only changes in init.el are uncommented go and lsp modules. There are no logs or error messages.

Describe your attempts to resolve the issue

It looks like it's indexing my project and its dependencies for autocompletion (I guess). The fact that it's Emacs that uses 100% CPU, not gopls, makes me think that.

The issue doesn't happen when go and lsp packages are not installed.

Steps to reproduce

1. brew install --cask emacs
2. git clone --depth 1 https://github.com/hlissner/doom-emacs ~/.emacs.d
3. ~/.emacs.d/bin/doom install
4. Open Emacs, edit init.el, uncomment go and lsp modules.
5. Run ~/.emacs.d/bin/doom sync and doom/reload.
6. Open a big Golang project or a project that uses a heavy dependency.

System Information

https://pastebin.com/rimY6Bre

[Jeiwan]

I debugged it a little bit more:

1. I left it running for several hours and it hadn't unfrozen.
2. The issue happens only when go-mode is installed with LSP support.
3. The issue happens only in one project. Other projects are ok.
4. It starts hanging a few seconds after LSP is initialized (a message is printed).
5. Reverting either lsp or go modes to older commits didn't help.
6. This doesn't happen in VSCode, even though it also uses LSP.

[Jeiwan]

Added this to config.el:

(setq lsp-go-gopls-server-args '("-logfile" "/Users/jeiwan/.tmp/gopls.log" "-vv" "-debug" ":8080"))

The log file is empty and there's nothing interesting on the debug server.

[Jeiwan]

Alright, I found the cause. That project has 170+ thousand files (not related to Go). When Emacs opens it, it starts analyzing them or maybe caching or maybe indexing – and this is when it hangs.

I installed Doom at commit 42d5da8. When I opened the project, it showed me this message:

There are 173301 files in folder ... so watching the repo may slow Emacs down. Do you want to watch all files in ... ? (y or n)

When choosing n it works without issues, when choosing y it hangs.

At commit 79c1fce, everything works without any issues and it doesn't ask about watching files.

It seems that a module was added that scans/analyzes/watches all files in a project and it just cannot handle so many files. If so, the question is: how to ignore those files? (They're ignored in .gitignore)

[jeetelongname]

What is the value of lsp-enable-file-watchers? back when I used to write go thats what caused the issue and it should be set to nil if not then you can set it to nil in go mode with this snippet

(setq-hook! 'go-mode-hook
     lsp-enable-file-watchers nil)

[Jeiwan]

@jeetelongname Thanks for pointing this out! However, I do need the watchers, so I simply added the cache folder to ignored ones:

(with-eval-after-load 'lsp-mode
  (add-to-list 'lsp-file-watch-ignored-directories "[/\\\\]cache\\'"))