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

[Juri Linkov]

>> Currently the main question is where to add display-buffer-in-related-window?
>> It should be added to display-buffer-fallback-action between
>> display-buffer-in-previous-window and display-buffer-use-some-window?
>> If not, then users should add it by customizing display-buffer-base-action?
>
> Hopefully it can be merged into 'display-buffer-in-previous-window'.

This is exactly what I already use in ~/.emacs, and it works nicely.
Any chance to add something like this optionally to window.el?

(defvar-local display-buffer-previous-window nil)

(add-to-list 'display-buffer-alist
             '((category . compilation)
               display-buffer-in-previous-window
               (previous-window . display-buffer-previous-window)))

(define-advice compile-goto-error (:around (ofun &rest args) previous-window)
  (let ((buffer (current-buffer)))
    (apply ofun args)
    (with-current-buffer buffer
      (setq-local display-buffer-previous-window (selected-window)))))

The main problem is where to set this buffer-local variable
(I think better to use the buffer-local variable instead
of the window parameter since visiting results from rgrep
is a property of the buffer, not the window).
Instead of the advice like above, 'display-buffer-previous-window'
should be set in every buffer displayed by 'display-buffer'.
Isn't setting this variable in all buffers too excessive?
But I see no other way because the user might want to
force displaying the results in the same rgrep window, then
display-buffer-in-previous-window should reuse the same window.