bug#65666: Lockfiles break package-vc-install-from-checkout

[Eli Zaretskii]

> From: Joseph Turner <joseph@breatheoutbreathe.in>
> Cc: Eli Zaretskii <eliz@gnu.org>, 65666@debbugs.gnu.org, adam.porter@47ap.net
> Date: Fri, 01 Sep 2023 16:43:27 -0700
> 
> 
> Philip Kaludercic <philipk@posteo.net> writes:
> 
> > LGTM, but I wonder if there is a better way to detect lockfiles
> > specifically?  If not, I can imagine that just using `file-exists-p'
> > would a too broad check, in the sense that it could make it difficult to
> > find other issues?
> 
> We could use a regex like
> 
> (unless (string-match-p (rx string-start ".#") file))

Or make the REGEXP argument to directory-files-recursively more
specific, to reject lock files.

But yes, the use of file-exists-p is not TRT, IMO.