bug#33870: 27.0.50; xref-goto-xref not configurable

[martin rudalics]

> The semantics is that they do what the default actions do
> plus something specific.  Maybe then move the default part
> from their body to some other fallback layer?  Then just use e.g.
> display-buffer-at-bottom, without the -maybe part.
> Or maybe use an alist for that, something like
>
>    ((maybe-try . default-actions))

I would never have written these "maybe" function in the first place.
They need more code lines then they spare.  So I have no real opinion.

>> (3) justify why the remaining 'display-buffer--maybe-' functions are
>> not public.
>
> I don't see any justification.

As we know all buffer display action functions are "maybe" functions
so people might ask why some of them include that word explicitly.

>> Also note that 'display-buffer' resizes a window iff that window is
>> new or always has shown the buffer to display before.
>>
>> There's one thing about 'display-buffer-at-bottom' that stupefies me:
>> Here
>>
>>             (let (split-width-threshold)
>>               (setq window (window--try-to-split-window bottom-window 
alist)))
>>
>> we bind ‘split-width-threshold’ so we can split the bottom window into
>> two side by side windows.  I recently found a branch of mine where I
>> bind 'split-height-threshold' to nil instead and now cannot remember
>> what we really wanted - split that window horizontally or vertically.
>> Can you?  In either case feel free to change that to what you consider
>> the more appropriate binding - maybe even binding both.
>
> It seems this code has no effect, it's never used.  Could you suggest
> such window configuration to test that would call it?

A single window frame where the buffer is not displayed runs this
part.

> There is another problem: in two small vertically split windows
> 'display-buffer-at-bottom' sometimes displays the buffer in the
> upper window.

From judging the code I'd say this is impossible.  But with Emacs
nothing is impossible.

martin