bug#71927: 29.4; ibuffer-do-isearch and ibuffer-do-isearch-regexp not prompting for input

[Eli Zaretskii <eliz@gnu.org>]

> Cc: 71927@debbugs.gnu.org
> From: Juri Linkov <juri@linkov.net>
> Date: Thu, 04 Jul 2024 09:58:18 +0300
> 
> > The commands ibuffer-do-isearch and ibuffer-do-isearch-regexp
> > do not prompt for an input search string.
> 
> They should not prompt because Isearch is interactive.
> But the problem is that they exit Isearch immediately.
> I tried to Edebug ibuffer-do-isearch, but this is
> not possible.

So did I, with the same results.

I also see that this didn't work at least as far back as Emacs 25,
maybe never.

The function ibuffer-do-isearch was added by you, and was never
changed before.  I guess it somehow violates the protocol of
define-ibuffer-op or something?  Admittedly, that protocol is not
described too well in the doc string.

I have a question: ibuffer-do-isearch just calls
multi-isearch-buffers.  Does multi-isearch-buffers exit immediately,
or does it exit only when the multi-isearch is done?  If the former, I
guess this is why the problem happens.

> So we need someone who knows ibuffer internals.

I've added two people who might be able to help.