bug#26980: 25.2; Freeze & redisplay_internal & macOS

[Robert Vojta]

> * 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)

9: file = 'xdisp.c', line = 17288, exact_match = 0, locations = 1, resolved = 
1, hit count = 225
    Breakpoint commands:
      p w->mode_line_height
      p (w->desired_matrix->rows + w->desired_matrix->nrows - 1)->height
      process continue

Never ending loop where CURRENT_MODE_LINE_HEIGHT(w) returns 21 and 
DESIRED_MODE_LINE_HEIGHT(w) returns 20.

(lldb)  p w->mode_line_height
(int) $587 = 21
(lldb)  p (w->desired_matrix->rows + w->desired_matrix->nrows - 1)->height
(int) $588 = 20
(lldb)  process continue
Process 75132 resuming
Command #3 'process continue' continued the target.
(lldb)  p w->mode_line_height
(int) $589 = 21
(lldb)  p (w->desired_matrix->rows + w->desired_matrix->nrows - 1)->height
(int) $590 = 20
(lldb)  process continue
Process 75132 resuming
Command #3 'process continue' continued the target.
(lldb)  p w->mode_line_height
(int) $591 = 21
(lldb)  p (w->desired_matrix->rows + w->desired_matrix->nrows - 1)->height
(int) $592 = 20
(lldb)  process continue
Process 75132 resuming
Command #3 'process continue' continued the target.
(lldb)  p w->mode_line_height
(int) $593 = 21
…

R.