bug#18136: 24.4.50; crash in redisplay when calling load-theme

[martin rudalics]

>> (gdb) xbacktrace al (C function)" (0xbbeea0)
>> "redisplay_internal (C function)" (0xbbeea0)
>> (gdb) bt
>> #0  terminate_due_to_signal (sig=sig@entry=6, 
backtrace_limit=backtrace_limit@entry=40) at emacs.c:359
>> #1  0x00000000004fe2e3 in emacs_abort () at sysdep.c:2198
>> #2  0x00000000004a81c1 in cmcheckmagic (tty=0x13d82a0) at cm.c:120
>> #3  0x0000000000418225 in update_frame_line (f=f@entry=0xc0ab08, vpos=50) at 
dispnew.c:4839
>
> Martin, this is because of this change in the call to
> change_frame_size by init_display:
>
>    @@ -6171,7 +6069,8 @@ init_display (void)
>         t->display_info.tty->top_frame = selected_frame;
>         change_frame_size (XFRAME (selected_frame),
>                      FrameCols (t->display_info.tty),
>    -                       FrameRows (t->display_info.tty), 0, 0, 1, 0);
>    +                       FrameRows (t->display_info.tty)
>    +                      - FRAME_MENU_BAR_LINES (f), 0, 0, 1, 0);
>
> change_frame_size_1 then calls adjust_frame_size with the value one
> less than the terminal height, and adjust_frame_size plugs that value
> into FrameRows:
>
>        if ((FRAME_TERMCAP_P (f) && !pretend) || FRAME_MSDOS_P (f))
>    FrameRows (FRAME_TTY (f)) = new_lines;
>
> This lies to Emacs about the terminal height, and cmcheckmagic catches
> that.
>
> I don't understand why you subtract FRAME_MENU_BAR_LINES, that sounds
> wrong at least for TTY frames.  (We could add that back inside
> adjust_frame_size, but it's IMO a bad idea to spread this non-trivial
> logic between 2 functions.)

All functions like change_frame_size or adjust_frame_size now expect the
frame's text height as argument and menu and tool bars should not be
part of it.  I was expecting some breakage of this approach for TTY
frames because I didn't fully understand the logic of how frames get
assigned sizes.  Probably this assignment

      if ((FRAME_TERMCAP_P (f) && !pretend) || FRAME_MSDOS_P (f))
        FrameCols (FRAME_TTY (f)) = new_cols;

is completely misplaced and should be either removed or inhibited when
called from change_frame_size_1, that is when INHIBIT equals 5.  Can you
tell me what this assignment is for?

martin