bug#1806: dired-pop-to-buffer in wrong place

[martin rudalics]

> Like Dired and Proced, VC shrinks the window to fit the buffer in
> `log-edit-show-files', so it could use `with-temp-buffer-window' too
> if it will retain the original behavior in the affected commands.

Maybe.  But when a buffer already exists, `with-temp-buffer-window' is
not suitable since it erases its contents.

> There is no need to combine specifiers and no need to add
> `temp-buffer-resize-regexps'.  In your current implementation
> it's perfectly possible to use the following call in `dired-mark-pop-up':
>
>      (with-temp-buffer-window
>       buffer
>       (cons 'display-buffer-below-selected
>             '((fit-window-to-buffer . t)))
>            ...
>
> and to add the following code to `display-buffer-below-selected'
> (copied and adapted from `dired-pop-to-buffer'):
>
> (defun display-buffer-below-selected (buffer alist)
>   "Try displaying BUFFER in a window below the selected window.
> This either splits the selected window or reuses the window below
> the selected one."
>   (let (window)
>     (or (and (not (frame-parameter nil 'unsplittable))
>         (setq window (window--try-to-split-window (selected-window)))
>         (window--display-buffer
>          buffer window 'window display-buffer-mark-dedicated))
>    (and (setq window (window-in-direction 'below))
>         (not (window-dedicated-p window))
>         (window--display-buffer
>          buffer window 'reuse display-buffer-mark-dedicated)))
>     ;; See Bug#12281.
>     (set-window-start window (point-min))
>     ;; If fit-window-to-buffer is t, make its window fit its contents.
>     (when (cdr (assq 'fit-window-to-buffer alist))
>       ;; Try to not delete window when we want to display less than
>       ;; `window-min-height' lines.
>       (fit-window-to-buffer window nil 1))
>     window))

How would we handle the case where `window--try-to-split-window' fails
for the selected window and some other window (like the frame's bottom
window) gets split?

>> Too many people don't like to automatically fit windows to
>> their buffers.  They must be able to turn that off.
>
> With the fixes above, users will be able to turn that off by customizing
> `display-buffer-alist' to the following value (this should be done via the
> Customization UI, but `setq' is used below for testing purposes):
>
> (setq display-buffer-alist '(("Marked Files" .
>                               (display-buffer-below-selected
>                                (fit-window-to-buffer . nil)))))

And how would they handle the frame bottom window case sketched above?

martin