bug#46397: 27.1; Cannot delete buffer pointing to a file in a path that includes a file

[Eli Zaretskii]

> From: Matt Armstrong <gmatta@gmail.com>
> Cc: 46397@debbugs.gnu.org, craven@gmx.net
> Date: Fri, 12 Feb 2021 15:59:40 -0800
> 
> > Nobody owns the lock _now_, but how did that come to happen?  We have
> > no idea.  It could be an indication that the user's files are under
> > attack, for example.  So silently assuming that the lock doesn't exist
> > is not necessarily TRT.
> 
> I think this portion of the discussion is on the fringe of the important
> issue.

For me, it _is_ the important issue.  This bug is just an indication
of a larger problem we have.

> Right now, 'current_lock_owner' can return arbitrary errno
> values, and if it does Emacs is in a bad situation:
> 
>  a) The user can't kill the buffer interactively.
>  b) Emacs can't exit, gets in a bad state, and must be killed.
> 
> So, definitely, we need to fix that.

So let's fix that instead of arguing, okay?

> Separately, I continue to think Paul's recent commit is fine.

I beg to differ: by solving that single aspect of a larger problem, it
makes the larger problem less urgent, and that runs high risk of
leaving it unsolved, IME.