bug#47366: 27.1; Tags search (regexp): FAILS

[Eli Zaretskii <eliz@gnu.org>]

> Cc: 47366@debbugs.gnu.org
> From: Lars Ingebrigtsen <larsi@gnus.org>
> Date: Mon, 27 Jun 2022 10:24:33 +0200
> 
> "Bob Floyd" <bobfloyd@comcast.net> writes:
> 
> > When I do a “tags-search FooFoo” sometimes the search stops in a
> > buffer at the wrong line. FooFoo is indeed in the buffer, but can be
> > many lines away from where emacs stopped. If I “kill-buffer” (C-x k)
> > and restart the “tags-search” then emacs stops at the correct line
> > where FooFoo is. I think this happens when I do a “tags-search”, make
> > edits in the buffer, then “save-some-buffers” (C-x s) followed by a
> > 2nd “tags-search” that then fails.
> >
> > It appears maybe that the regex compiler isn’t run after the edits?
> >
> > Sorry I can’t provide an exact sequence of commands for you to see it,
> > it doesn’t happen always (maybe it doesn’t even stop in the buffer and
> > I don’t notice), but perhaps you can recognize the issue.
> 
> (I'm going through old bug reports that unfortunately weren't resolved
> at the time.)
> 
> I tried reproducing this in Emacs 29, but was unable to.  But I'm not
> sure I'm testing the right thing.

It is not clear from the recipe whether the OP re-runs etags to
regenerate the TAGS file after making significant changes top the
source files.  If etags is not re-run, the TAGS file could be outdated
more than the slack we allow, and then the problem description would
make sense.