bug#18133: Suppressing asynchronous command output

[Eli Zaretskii <eliz@gnu.org>]

> Date: Sat, 24 Dec 2016 17:33:01 +0100
> From: martin rudalics <rudalics@gmx.at>
> CC: rrt@sc3d.org, 18133@debbugs.gnu.org
> 
>  > I'm not talking about any code that would change the default value.
>  > I'm talking about showing the users a non-default value, for them to
>  > select if they want to, that would produce the effect desired here.
>  >
>  > IOW, when the user clicks "Value menu", I would like them to see a
>  > value which makes async shell buffers behave like Reuben wants.
>  > That's all.
> 
> If that's all, just add ‘display-buffer-no-window’ to
> ‘display-buffer--action-function-custom-type’ as I suggested before.
> (BTW Juri should have done that when he added that function.)  But
> Reuben replied
> 
>    It would be nice if the user only had to change one thing to enable hiding
>    the async output buffer until there is output. If we only added the
>    function to display-buffer--action-function-custom-type, the user still has
>    to manually add the right buffer name pattern and the action to
>    display-buffer-alist.

Yes, I meant to add a value that would handle "*Async Shell Output*"
buffer like described above.

>  > We are not talking about any applications, at least I wasn't.  I was
>  > talking about providing another possible value, that'd be easy to
>  > select without writing any Lisp, and which, when selected, will cause
>  > the async shell output buffer be displayed only when there's some
>  > material in it.
> 
> And how should ‘display-buffer’ know whether "there's some material" in
> that buffer?

That's up to Reuben, I thought he had this figured out already.