Re: OSX FSEvents file watching support

[Eli Zaretskii]

> Date: Thu, 18 Jul 2019 08:14:33 -0700
> From: "Muir Manders" <address@hidden>
> Cc: address@hidden
> 
> lsp-mode in particular needs to watch your entire source code project for 
> file changes and then relay the file names that were created/modified/deleted 
> fo the LSP server. This is to handle when files change outside the editor, 
> like when changing branches. The LSP server registers file globs for the 
> types of files it wants to receive notifications for, which is normally just 
> the source code files and maybe some project metadata files (e.g. "**/*.go" 
> to watch Go files). The LSP spec delegates file watching to the editor 
> because file watching is hard, and in general there are fewer LSP clients 
> (editors) than LSP servers.
> 
> The current (kqueue, at least) backends must open many file descriptors to 
> watch a large directory tree. FSEvents however can do this task efficiently.

Beware: like I said earlier, I don't expect these facilities to be
scalable enough for watching large trees that get a lot of frequent
changes.  AFAIK, lsp-mode developers recommend to turn off file
notifications when there are a lot of them.