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

[Eli Zaretskii <eliz@gnu.org>]

> Cc: craven@gmx.net, 46397@debbugs.gnu.org, Matt Armstrong <gmatta@gmail.com>
> From: Paul Eggert <eggert@cs.ucla.edu>
> Date: Wed, 10 Feb 2021 11:23:46 -0800
> 
> --- a/src/filelock.c
> +++ b/src/filelock.c
> @@ -532,7 +532,7 @@ current_lock_owner (lock_info_type *owner, char *lfname)
>    /* If nonexistent lock file, all is well; otherwise, got strange error. */
>    lfinfolen = read_lock_data (lfname, owner->user);
>    if (lfinfolen < 0)
> -    return errno == ENOENT ? 0 : errno;
> +    return errno == ENOENT || errno == ENOTDIR ? 0 : errno;

As I said, I don't think this is TRT.  Why should we silently ignore
ENOTDIR? couldn't it mean some kind of malicious attack on the user's
account, or some other trouble?

We should not ignore these errors, we should ask the user what to do
about them.  The user can tell us the error can be ignored, but we
should not decide that without asking.