Allow toggling "watch_gitdir" or dynamically changing watch interval

[mars90226]

Is your feature request related to a problem? Please describe.
I work for the project that consisted of many small git repos. Usually I open each neovim instance for each git repo and switch between them. I would like to avoid or lower the CPU usage of gitsigns.nvim "watch_gitdir" in background neovim instances.

Describe the solution you'd like
A command to toggle "watch_gitdir" or change "watch_gitdir" interval.

Describe alternatives you've considered
Automatically disable "watch_gitdir" in background neovim instances.

Additional context
I've tried to implement this in my config by trying to change directory to non-git directory on FocusLost and changing back on FocusGained. But the debounced update_cwd_head function seems not called when triggered this way.

[lewis6991]

Can't you just disable config.watch_gitdir?

I'm really not interested in adding a dynamic. Having a poll object for each open buffer shouldn't use much CPU.

[mars90226]

Well, the watcher does create many epoll_pwait()s on my machine and raise the load averages quite a lot if I open many neovim instances. Maybe I just raise the interval to 60 seconds to workaround this. Thanks anyway!

[lewis6991]

Are you talking about the cwd_watcher or the gitdir watcher? The gitdir_watcher can be disabled.

[mars90226]

Oops, I think I may traced the wrong code 😅 I tried to reduce the epoll_pwait() numbers and grepped new_fs_poll() to find out. I found that gitsigns.nvim cwd_watcher is using the new_fs_poll() and think it's the culprit. But it's actually the gitdir_watcher that cause all the epoll_pwait()?

[mars90226]

I know I can disable watch_gitdir with enable = false. But I want to enable it when I'm actually using the neovim (it's in the foreground).

[lewis6991]

There are a few improvements we can make:

• Use fs_events instead of polling. I've started this in feat(watcher): move from libuv poll to file event watcher #660
• Share watchers across buffers apart from the same repository. Currently, each buffer gets its own watcher.
• Stop the watchers when nvim is backgrounded. Or better: stop watchers after the first trigger when nvim is backgrouned since any subsequent callbacks aren't doing anything useful.

I've raised #823 to track this. I don't plan on working on this soon, so PR's would be welcome if you're feeling up to it.

[mars90226]

Thanks! I'm not familiar with libuv, but I can try stopping watchers when nvim is backgrounded when I have free time.