bug#20020: 25.0.50; `info-display-manual' should reuse existing window where buffer is displayed

[Lars Ingebrigtsen <larsi@gnus.org>]

Drew Adams <drew.adams@oracle.com> writes:

> In my case, Info buffers (*info* and *info<N>*) are in dedicated
> windows.  I expect `info-display-manual' to select such an existing
> window.  That is, if the Calc manual is already displayed in an Info
> buffer and I use `M-x info-display-manual' from some other buffer, I
> expect the existing window showing that manual to be selected (and its
> frame raised and focused, if necessary).
>
> Instead, `info-display-manual' displays the manual in the same window
> where I invoke it, resulting in two windows (and frames in my case)
> showing the same Info manual.

Makes sense.  I've now done this in Emacs 27, but while writing the
code, it struck me that there has to be a ready-made function for this
somewhere already.  I had a peek through the plethora of
switch-to/pop-to functions, but I didn't find anything that did exactly
this...

Does anybody know?  In short: If there's a window that has the buffer,
then that window should be selected, and its frame popped to the top
(and given focus).  If not, it should work like `switch-to-buffer'.

-- 
(domestic pets only, the antidote for overdose, milk.)
   bloggy blog: http://lars.ingebrigtsen.no