bug#8865: 24.0.50; `display-buffer' does not respect `pop-up-frames'

[Drew Adams]

> >> > My question was about replacing such a test.  The common 
> >> > denominator of the intentions behind using such tests is
> >> > what all of those tests do (have in common): distinguish
> >> > nil `pop-up-frames' from non-nil.  Nothing more.
> >> If that's all you want to do, then "(if pop-up-frames" is 
> >> (trivially) the only answer.
> 
> > Well, yes, in Emacs 20-23.  But if `pop-up-frames' is being 
> > deprecated then what is the _replacement_ for such a test,
> > going forward?
> 
> If your point is to test pop-up-frames, then by all means do that.

No, why do you keep saying that?

My point _in Emacs 20-23_ was to test `pop-up-frames'.  I'm looking to do for
Emacs 24+ whatever is appropriate, to get the same or very similar behavior.

My point is _not_ to test `pop-up-frames' in Emacs 24+, but to test whatever is
now recommended instead of `pop-up-frames', in order to get the same/similar
behavior as before.

Don't you have the same problem in the Emacs sources?  There are plenty of tests
of `pop-up-frames' there.  How will you be replacing them?

I have only two such tests in my code.  I'm trying to learn what to do in their
stead.  You say in effect "don't test `pop-up-frames' anymore", and my question
is OK, what do I test instead to get the same effect?

> And if it disappears, then change your code so it doesn't signal
> an error.  As long as you don't give me the intention behind the
> check, there is no better answer.

The intention (in Emacs < 24) was to key the code's behavior off of
`pop-up-frames' as specified by the user, in order to DTRT based on the
intention about `display-buffer' and separate frames that the user communicated
via `pop-up-frames'.

For Emacs 24+ the intention is to key the behavior off of the new variable that
replaces `pop-up-frames', whatever it is.  I realize that there is no simple
variable that corresponds to `pop-up-frames'.  I'm asking about whatever is
equivalent (as much as possible) and can be similarly tested - presumably some
part of `display-buffer-alist'.  What is an equivalent test, for `d-b-a'?