bug#48249: 28.0.50; Regression: emacs confused about window configuration due to ido-mode and/or winner-mode

[Alan Mackenzie]

Hello, Gregory.

On Fri, May 07, 2021 at 12:02:14 +0000, Gregory Heytings wrote:

> >
> > diff --git a/lisp/winner.el b/lisp/winner.el
> > index f30fa6cf5c..a60ef44662 100644
> > --- a/lisp/winner.el
> > +++ b/lisp/winner.el
> > @@ -212,7 +212,7 @@ winner-set-conf
> >          (minisize (window-height miniwin)))
> >     (cl-letf (((window-buffer miniwin))
> >               ((window-point  miniwin)))
> > -      (set-window-configuration winconf))
> > +      (set-window-configuration winconf nil t))
> >     (cond
> >      ((window-live-p chosen) (select-window chosen))
> >      ((window-minibuffer-p) (other-window 1)))
> >

> This cannot be the right way to fix the bug.  That line was last changed 
> more than 20 years ago (commit 2a92dc2540 by RMS).

I agree it isn't the best way to fix the bug, because that fix isn't
robust enough.  But it's hopefully good enough to relieve the irritation
of the original poster for a short while, while I work on something
better.  It's also good enough to check whether the cause of the bug has
actually been found.  That the source line was last changed so long ago
is neither here nor there.

> Or does that mean that from now on each occurrence of 
> 'set-window-configuration' (there are 98 occurrences in the Emacs core 
> only) should take an additional dont-set-miniwindow t argument to avoid 
> that bug?

That is the problem.  Some of these calls might need the extra argument,
most of them won't.  Such a requirement would be a poor abstraction,
since the typical caller of set-window-configuration shouldn't have to
worry about such details.

By the way, thanks for the service you're providing of identifying bugs
connected with the recent minibuffer changes.  It's appreciated!

-- 
Alan Mackenzie (Nuremberg, Germany).