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

[zhanghj <ccsmile2008@outlook.com>]

How does it work in Emacs 26/27? Why don't you let it keep the old behavior?

I just tried again with the following test code(with 
auto-revert-interval be a big value). There was a long delay(about 30s) 
before the first reverting. But the following ones were instant.

(progn
   (setq auto-revert-use-notify t
         auto-revert-interval 30)
   (global-auto-revert-mode 1)
   (setq find-file-hook (delq 'vc-refresh-state find-file-hook))
   (find-file "~/symlink_dir/abc.txt"))


On 9/13/23 21:33, Michael Albinus wrote:
> Eli Zaretskii <eliz@gnu.org> writes:
>
> Hi,
>
>>> 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.
> Yes, we don't support autorevert of files in a symlinked directory via
> file notifications. There are other bugs with the same topic, see
> bug#16113, bug#18883 and bug#64061. I'll merge this bug with the other
> ones.
>
>> A workaround is to set auto-revert-use-notify to nil.
> Yep.
>
> Best regards, Michael.