bug#67687: Feature request: automatic tags management

[Eli Zaretskii <eliz@gnu.org>]

> Date: Sun, 31 Dec 2023 01:58:55 +0200
> Cc: 67687@debbugs.gnu.org, eskinjp@gmail.com
> From: Dmitry Gutov <dmitry@gutov.dev>
> 
> On 31/12/2023 01:25, Stefan Kangas wrote:
> > Dmitry Gutov <dmitry@gutov.dev> writes:
> > 
> >> On 30/12/2023 22:31, Stefan Kangas wrote:
> >>
> >>> Would it be helpful to put that explanation in the .dir-locals.el file
> >>> itself?
> >>
> >> .dir-locals.el already usually hosts per-project settings. And most
> >> users of this feature probably aren't going to read Emacs's one.
> > 
> > I was mostly thinking about us poor Emacs maintainers, but either way is
> > fine by me.
> 
> Speaking of maintainers, I'm curious if I'll ever see the day when 'make 
> tags' outputs "Use 'M-x etags-regen-mode' instead" ;-)

I don't yet see why we'd need that.  As one data point, my TAGS files
in the Emacs repository were generated in Feb 2023, and I still use
them almost every day without any visible problems.  And for Lisp
code, M-. doesn't use TAGS by default anyway.

Unlike "indexing" in other IDEs, the Emacs tags commands are well
equipped to cope with changes in sources, and don't fail
catastrophically when there are such changes, as long as functions and
variables don't move between files.  The auto-regen mode might be
needed for some projects where source files change significantly at
high pace, but not in Emacs, at least not IME.

So whether this mode should be turned on by default is something that
is yet to be seen.  Let's not hurry and make decisions in haste,
certainly not wrt the use of this as part of Emacs maintenance.