bug#74666: 31.0.50; Regression in replace-match with empty-adjacent groups

[Eli Zaretskii <eliz@gnu.org>]

> Cc: 74666@debbugs.gnu.org
> Date: Mon, 16 Dec 2024 22:18:57 -0500
> From:  Stefan Monnier via "Bug reports for GNU Emacs,
>  the Swiss army knife of text editors" <bug-gnu-emacs@gnu.org>
> 
> > In this case, the match data is set with `set-match-data' using
> > calculated ranges.
> 
> I guess we can take this as good thing: it means complexifying the
> regexp code would be wasted.  🙂
> 
> > Since this used to work I think it's reasonable to consider it a regression.
> 
> I was not trying to say it's not a regression.  Just pouting because the
> old behavior was just a lucky accident and recovering it without losing
> the other improvement isn't completely straightforward.
> 
> > I've since committed a workaround to evil-numbers [1], although I'd suspect
> > this would impact others.
> 
> [ And the workaround relies on another lucky accident: the "easiest"
>   fix for the problem would break your workaround. 🙁  ]

What should we do with this bug report?