bug#70900: 30.0.50; tramp complains "File error: Cannot remove lock file for /ssh:..." on every save when remote-file-name-inhibit-locks is non-nil

[Eli Zaretskii <eliz@gnu.org>]

> Cc: 70900@debbugs.gnu.org
> Date: Mon, 13 May 2024 07:56:29 +0200
> From:  Michael Albinus via "Bug reports for GNU Emacs,
>  the Swiss army knife of text editors" <bug-gnu-emacs@gnu.org>
> 
> Dmitry Gutov <dmitry@gutov.dev> writes:
> 
> Hi Dmitry,
> 
> > 1. (setq remote-file-name-inhibit-locks t)
> > 2. Open some file remotely, lightly edit and save it.
> > 3. See this message in the Messages buffer.
> 
> The description of remote-file-name-inhibit-locks says "Whether to
> create file locks for remote files.". And this is what Tramp
> does. Nothing said about checking/removing of lock files.
> 
> If we want to suppress these actions as well, we shall agree about, and
> change the doc. Eli?

I think making the failure to remove be silent in this case is enough.
If the user sets this variable to t, they are not interested in
failures to remove lock files, even if it's for reasons other than
"file does not exist".

IOW, it's okay to try to remove lock files, but if that fails, Emacs
should not display any error messages.

> > It would also make sense to switch it on by default - it has a
> > noticeable effect on performance.
> 
> No. File locks are an essential part of Emacs. Disabling them has the
> potential to damage something (see above), so it shall be decided by the user.

Agreed.