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

[Eli Zaretskii]

> From: Juri Linkov <juri@linkov.net>
> Cc: dgutov@yandex.ru,  joaotavora@gmail.com,  44611@debbugs.gnu.org
> Date: Sun, 20 Dec 2020 10:39:25 +0200
> 
> >> Therefore, I propose this patch that binds TAB and S-TAB to command
> >> that behave like compilation-next-error and compilation-previous-error:
> >
> > This is an incompatible behavior change, no?  If so, I'm not sure we
> > can simply make it.
> 
> This is what we have the section "Incompatible Editing Changes" in etc/NEWS 
> for.

The fact that the section exists doesn't mean we can make incompatible
changes whenever we feel like.  This key binding existed since Emacs
26.1, so changing it would definitely surprise someone.

> And since the new keybinding have no disastrous effect, it would safer
> for the users to adapt to the new keybinding.

What disastrous effects?  AFAICT, TAB buries the XREF buffer, which is
not a disaster.

More generally, I think it's wrong to try to make XREF buffers behave
like *Grep* buffers.  They are different beasts, I think we
established this long ago, when Xref was added to Emacs (I think I
even made a comment regarding the difference, and Dmitry responded to
the effect that this was intended).  *XREF* and *Grep* look
differently and behave differently, and it's impossible to make them
be similar enough.

So I'm against this change, certainly if it's unconditionally changes
the key binding.