bug#47894: 28.0.50; isearch does not work if enable-recursive-minibuffers is on and some input method is set.

[Gregory Heytings]

> > > For users (eq (current-buffer) (window-buffer)) _should_ be invariant. 
> > > When and if an application temporarily violates that invariant, it 
> > > should reestablish it before the user can see it.  So if an 
> > > application calls `display-buffer' in a state where the invariant does 
> > > not hold, it should handle that case including the complication that 
> > > `display-buffer' might have selected another window.  And it goes 
> > > without saying that a display buffer action should never violate that 
> > > invariant.
> >
> > I see.  So in this case the bug was elsewhere as I thought, it's 
> > display-buffer-select which was wrong (as you said it should have used 
> > pop-to-buffer) and not the code I added in isearch-post-command-hook. 
> > Anyway using (window-buffer (selected-window)) should not harm, and is 
> > an extra safety against display buffer actions doing something weird.
>
> As this bug report indicates, automatically exiting isearch does more 
> harm.

I guess it's a matter of interpretation here.  In this bug report isearch 
was automatically exited by error, because isearch-post-command-hook is 
executed inside the minibuffer (I'm not sure it should be).

On the contrary, what Zhiwei Chen asked is what the patch does: exit 
isearch when point has moved to another window at the request of the user.

> So rather than forcibly exit isearch, we could select the original 
> window back, in the same vein as isearch-back-into-window in the same 
> hook moves point back to the old window boundaries:

That would be the opposite of what Zhiwei Chen asked (twice), but I won't 
fight for him.