bug#68081: 30.0.50; derived-mode and display-buffer-alist

[martin rudalics]

> Thanks.  This is a significant change, so probably not suitable for
> the release branch.  Do you think the simple change of using the old
>
>       (if (get-buffer "*info*")
>    (pop-to-buffer "*info*")
>         (Info-directory))))
>
> is okay for installing on the release branch,

Where would we do that?  The context for that snippet has vanished long
ago and we need a buffer we can pass to 'info-setup'.

> or would you recommend
> to leave the release branch without a fix and only fix this on master?

Only fix this on master.  The warning for 'buffer-match-p' would be
needed for both - release branch and master - anyway.  Who knows how
many cases similar to this we have.

martin