Subject: bug#63967: 28.2; switch-to-buffer in normal window fails if minibuffer window is active

From: Stefan Monnier <[email-masked]>
Date: Sat, 10 Jun 2023 11:49:43 -0400

Hi Alan,

Could you explain why/when we need to call `Fset_frame_selected_window`
in the code below:

>   static void
>   minibuffer_unwind (void)
>   {
>     struct frame *f;
>     struct window *w;
>     Lisp_Object window;
>     Lisp_Object entry;
>
>     if (NILP (exp_MB_frame)) return; /* "Can't happen." */
>     f = XFRAME (exp_MB_frame);
>     window = f->minibuffer_window;
>     w = XWINDOW (window);
>     if (FRAME_LIVE_P (f))
>       {
> 	/* minibuf_window = sf->minibuffer_window; */
> 	if (!NILP (w->prev_buffers))
> 	  {
> 	    entry = Fcar (w->prev_buffers);
> 	    w->prev_buffers = Fcdr (w->prev_buffers);
> 	    set_window_buffer (window, Fcar (entry), 0, 0);
> 	    Fset_window_start (window, Fcar (Fcdr (entry)), Qnil);
> 	    Fset_window_point (window, Fcar (Fcdr (Fcdr (entry))));
> 	    /* set-window-configuration may/will have unselected the
> 	       mini-window as the selected window.  Restore it. */
> 	    Fset_frame_selected_window (exp_MB_frame, window, Qnil);  <<<<<<<<<
> 	  }
> 	else
> 	  set_window_buffer (window, nth_minibuffer (0), 0, 0);
>       }
>   }

I understand why we do the `set_window_buffer` and set its start and
point, but I can't see why we'd need to select the mini-window:
presumably if it needed to be (re)selected that should have been handled
by the window-config save&restore, no?

        Stefan