bug#70949: display-buffer-choose-some-window

[martin rudalics via "Bug reports for GNU Emacs, the Swiss army knife of text editors" <bug-gnu-emacs@gnu.org>]

 >> In that latter case, 'vc-diff' could pass an extra optional argument to
 >> 'vc-diff-internal', telling it that it has to call 'pop-to-buffer' with
 >> a 'display-buffer-in-previous-window' action and a 'previous-window'
 >> alist entry whose value is 'vc-diff'.  That's all 'vc-diff' can do.
 >
 > This doesn't look like a nice design to require changing the signatures
 > of vc functions.

We don't have to.  But then we can forget the idea of identifying the
first in a sequence of related operations.

 > I think such design looks overly complicated.  I hoped for something
 > much simpler by adding just a few lines to window.el.

We have to make up our minds on what we want.  I think the primary aim
is to display a series of related buffers in one and the same window.
Where and when do we want that?  So far we discussed two functions -
'vc-diff' and 'compile-goto-error'.  I think that at the very least we
have to encompass all flavors of 'next-error' as well.

Then we can look into how the clients of 'display-buffer' can support
it.  Finally, we can decide how many lines of code we have to change in
window.el.

martin