bug#65904: 29.1.50; autorevert can't revert files in a symlink directory

[Eli Zaretskii]

> From: Zhang Haijun <ccsmile2008@outlook.com>
> Date: Wed, 13 Sep 2023 03:55:15 +0000
> 
> 
> It works in Emacs 26/27, But it doesn't work in Emacs 29.
> 
> 0. emacs -Q
> 1. use the following code to open an existing file in a symlink directory
> (progn
>   (setq auto-revert-use-notify t
>             auto-revert-interval 3)
>   (global-auto-revert-mode 1)
>   (setq find-file-hook (delq 'vc-refresh-state find-file-hook))
>   (find-file "~/symlink_dir/test.txt"))
> 
> 2. modify the test file in external program and save
> 3. emacs doesn't autorevert the file

AFAICT, we don't support autoreverting symlinks, since Dec 2013, so it
sounds strange that you say it worked in Emacs 27.

The relevant discussion is here:

  https://lists.gnu.org/archive/html/emacs-devel/2013-12/msg00282.html

The reason for this non-support seems to be performance.

I hope Michael (CC'ed) will be able to tell more about this.

A workaround is to set auto-revert-use-notify to nil.