bug#74361: [PATCH] New option xref-navigation-display-window-action

[martin rudalics via "Bug reports for GNU Emacs, the Swiss army knife of text editors" <bug-gnu-emacs@gnu.org>]

 > Ok.  This reminds me adding '(previous-window . WINDOW)'
 > to 'display-buffer-in-previous-window' with:
 >
 >      (when (and previous-window (symbolp previous-window)
 >                 (boundp previous-window))
 >        (setq previous-window (symbol-value previous-window)))

Where and how is or would this be used?  In the sources all I see is

		          `((previous-window . ,debugger-previous-window))))))

so I suppose the symbol value would be used in customizations only.

 >      (when (and (setq window previous-window)
 > 	       (window-live-p window)
 >
 > Probably we should support both a symbol and a value for 'some-window'
 > as well.

Where and how would this be used?

 > BTW, here is an example of using 'previous-window' with an advice on
 > 'window--display-buffer' that could be combined with 'some-window':
 >
 >    (defvar-local display-buffer-previous-window nil)
 >
 >    (add-to-list 'display-buffer-alist
 >                 '((category . xref-jump)
 >                   display-buffer-in-previous-window
 >                   (previous-window . display-buffer-previous-window)

So here 'display-buffer' would retrieve the symbol-value of whatever is
in the buffer-local value of 'display-buffer-previous-window'.  Right?

 >                   (inhibit-same-window . nil))
 >                 ;; Append to not override display-buffer-same-window
 >                 'append)
 >
 >    (define-advice xref-goto-xref (: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)))))

This relies on 'ofun' selecting a window and would not work for plain
'display-buffer'.  Right?

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

And this assumes that the current buffer is the one where to set the
variable.  Would this work with a function calling 'xref-goto-xref',
bound to a key and called interactively with an arbitrary window
selected?

martin