bug#26980: 25.2; Freeze & redisplay_internal & macOS

[Robert Vojta]

Hi,

found some time to continue with this issue. fonts_changed are modified here:

* thread #1, queue = 'com.apple.main-thread', stop reason = breakpoint 4.1
    frame #0: 0x0000000100092643 Emacs`redisplay_window(window=4836536885, 
just_this_one_p=false) at xdisp.c:17288
   17285              if (WINDOW_WANTS_MODELINE_P (w)
   17286                  && CURRENT_MODE_LINE_HEIGHT (w) != 
DESIRED_MODE_LINE_HEIGHT (w))
   17287                {
-> 17288                  f->fonts_changed = true;
   17289                  w->mode_line_height = -1;
   17290                  MATRIX_MODE_LINE_ROW (w->current_matrix)->height
   17291                    = DESIRED_MODE_LINE_HEIGHT (w);
(lldb)

It’s pretty hard to say why this happens, because I know nothing about Emacs 
internals. Going to focus on CURRENT_MODE_LINE_HEIGHT(w) and 
DESIRED_MODE_LINE_HEIGHT(w).

R.