Subject: bug#33258: inhibit-select-window

From: martin rudalics <[email-masked]>
Date: Mon, 05 Nov 2018 10:34:17 +0100

> Many commands use pop-to-buffer to display a buffer and
 > select its window by default.
 >
 > Sometimes it's not desirable to select the displayed window.
 >
 > One of the many examples is 'C-x v =' (vc-diff) where
 > the need is only to look at the diffs, but not to operate
 > on the *vc-diff* buffer in its window.

Is this particular behavior caused by the

       ;; Display the buffer, but at the end because it can change point.
       (pop-to-buffer (current-buffer))

in 'vc-diff-internal'?

 > Currently there is no configurable way for the user
 > to override the default window selection.
 >
 > I propose a new alist entry to support such feature.
 > An example of usage in user's customization:
 >
 >    (push '("\\*vc-diff\\*" nil
 >            (inhibit-select-window . t))
 >          display-buffer-alist)
 >
 > then pop-to-buffer could check for the alist entry
 > 'inhibit-select-window' and to not select the window
 > if it's non-nil.

I understand what you want but I doubt we can put that into practice.
While not selecting the window might not be a great issue, not making
its buffer current is.  We would have to check each and every call of
'pop-to-buffer' as to whether subsequent code relies on the fact that
it made the buffer current.  This is not fathomable IMO.

One could argue that 'display-buffer' may fail to produce a window and
so the buffer would not be made current in that case either but as we
know it is really hard to make 'display-buffer' fail.

 > OTOH, when a command uses display-buffer that doesn't select a window,
 > then the same alist entry with a different value or a new entry e.g.
 > '(select-window . t)' could be used to force selecting the window.
 > This could be implemented by using the same code from pop-to-buffer
 > and adding it to display-buffer functions.

This would be possible.  Such an entry would have to be called
something like 'force-select-window' and could be applied by both
users and programs for one soberingly simple reason: A Lisp program
can never rely upon 'display-buffer' to _not_ select the chosen window
- popping up a new frame may implicitly select the window at any time.

martin