bug#44611: Prefix arg for xref-goto-xref

[Eli Zaretskii]

> Cc: joaotavora@gmail.com, 44611@debbugs.gnu.org
> From: Dmitry Gutov <dgutov@yandex.ru>
> Date: Thu, 24 Dec 2020 23:38:52 +0200
> 
> On 24.12.2020 05:36, Eli Zaretskii wrote:
> 
> > Why does project-find-regexp need to use Xref for displaying the hits?
> > why not use Grep-like display we use in *grep* buffers?
> 
> These days the default Xref buffer is pretty much Grep-like. Certainly 
> much closer to grep-mode than it had been in the first versions. That 
> old UI was a lot more completion-like in its behavior.
> 
> This happened gradually, after we have addressed feedback from you and 
> other users, so that xref-find-references and project-find-regexp behave 
>   more in a fashion that you would expect from it. And those 
> expectations were surely informed by Grep and other built-in modes.

Then why do we need to have 2 separate modes?  Are there any plans for
replacing grep-mode with xref-mode in all the commands that use the
former?  Do we also want to replace compilation-mode with xref-mode?

If the plan is to make such replacements, that could be a good idea,
and we can discuss the roadmap towards that goal.  Such a roadmap
should include a transition plan that will help people migrate as
painlessly as possible, including the key bindings and the somewhat
different looks.  And perhaps _then_ we will have a good enough reason
we don't have now to rebind xref-mode's TAB in Emacs 28.

I didn't see any discussions to that effect, and in any case such
discussions need to be on emacs-devel, not here.  If the intent is
indeed to make such a migration, let's announce the plan, and let's
define the roadmap which we want to follow.  It's a significant
change, and we should be careful in how we do it.