Re: Proposed removal of struct frame->select_mini_window_flag.

[Eli Zaretskii <eliz@gnu.org>]

> Date: Wed, 18 May 2022 17:03:13 +0000
> Cc: emacs-devel@gnu.org
> From: Alan Mackenzie <acm@muc.de>
> 
> >   sf->select_mini_window_flag = MINI_WINDOW_P (XWINDOW (sf->selected_window));
> 
> >   selected_frame = frame;
> 
> >   move_minibuffers_onto_frame (sf, for_deletion);
> 
> >   if (f->select_mini_window_flag
> >       && !NILP (Fminibufferp (XWINDOW (f->minibuffer_window)->contents, Qt)))
> >     f->selected_window = f->minibuffer_window;
> 
> Yes, I saw it.
> 
> > How will this logic work without that flag?
> 
> There is no logic which uses it.

How do you mean "no logic"?  I mean this logic, right there:

  if (f->select_mini_window_flag
      && !NILP (Fminibufferp (XWINDOW (f->minibuffer_window)->contents, Qt)))
    f->selected_window = f->minibuffer_window;


> These lines in frame.c set the flag in
> sf (the old frame), and test it in f (the new frame).  It is intended to
> be a durable flag saying whether or not the mini-window in a non-selected
> frame is to be selected at the next do_switch_frame () into it.  This
> might make sense if there were something setting f->selected_window without
> going through the proper functions.

The code above does just that, does it not?  It directly sets
f->selected_window.

> What we do have is the setting of the flag unconditionally to false in
> select_window (window.c), with no attempt being made to save and restore
> the current value.  Considering that Fselect_window can be called from
> gui_consider_frame_title (xdisp.c) during a redisplay (with the current
> bug fix), this means the flag can be initialised to false asynchronously
> at any time.

What do you mean by "asynchronously"?  gui_consider_frame_title is not
called asynchronously, at least under my interpretation of that term.