Re: selected-frame and selected-window

[Eli Zaretskii <eliz@gnu.org>]

> From: Stefan Monnier <monnier@iro.umontreal.ca>
> Cc: emacs-devel@gnu.org
> Date: Sat, 08 Dec 2012 18:51:40 -0500
> 
> >> > This is assertion violation in redisplay_internal, here:
> >> >       eassert (EQ (XFRAME (selected_frame)->selected_window,
> >> >                    selected_window));
> >> > This crash is probably of the kind you reported in the past, related
> >> > to the selected-frame/selected-window issues.
> >> I'm not sure is that assertion is actually right.
> > Well, "bzr annotate" says you added it ;-)
> > Should we just go ahead and remove it?  Inaccurate assertions are a
> > maintenance headache, to say nothing of user aggravation.
> 
> The rest of my message mentioned reasons why the equality is
> sometimes broken.

Yes, I know.  But a broken assertion is a candidate for removal, IMO.

> Now, I tend to consider that those cases should be considered bugs,
> because IIRC there are cases where we do rely on this equality.

If you or someone else can describe those cases, we could use that
knowledge to modify the assertion or fix the bugs which violate it.

> More specifically, I added such easserts in an effort to track the
> origin of an error.

We are evidently unable to do that in a long time.  All we do is cause
user aggravation and add to maintenance load.

> But to fix these bugs we need to figure out how to handle the "mode-line
> :eval" case.

Do you have any practical suggestions for that?