bug#39822: 27.0.90; Cannot set *Completions* buffer height using display-buffer-alist

[Juri Linkov]

>> Here is a complete list of commands that use
>> with-displayed-buffer-window:
>>
>> - dired-mark-pop-up
>> - minibuffer-completion-help
>> - save-buffers-kill-emacs
>>
>> What they all have in common is that they have some post-processing
>> in the displayed buffer.  I wonder why there are no more such commands
>> that need to do such post-processing?  Maybe they use some simpler
>> solution that could be used here as well?
>>
>> For example, hack-local-variables-confirm uses just
>>
>>    (pop-to-buffer "*Local Variables*" '(display-buffer--maybe-at-bottom))
>
> IIUC it neither runs the hooks for temporary buffers nor does it obey
> 'temp-buffer-resize-mode'.

I don't know why it should run hooks and 'temp-buffer-resize-mode'.
Why other clients of display-buffer don't need these hooks?

>> and nothing more, without hassles of with-displayed-buffer-window.
>> And still it fits the window nicely into the buffer height.
>
> How comes?

Maybe this means it's possible to avoid using with-displayed-buffer-window?

>> Why the above 3 commands couldn't do the same by abandoning
>> with-displayed-buffer-window?
>
> It depends on how much of the stuff in 'temp-buffer-window-setup' and
> 'temp-buffer-window-show' they really need.

Maybe they need none of these?