bug#7348: 23.2.50; Emacs crashes on fast window resize with scrollbars on under OSX

[YAMAMOTO Mitsuharu]

>>>>> On Sat, 6 Nov 2010 21:20:03 +0000, Jakub Turski <yacoob@gmail.com> said:

> Method to replicate:
> 1/ Compile recent OSX Emacs from 'emacs-23' branch
> 2/ Launch 'emacs -Q'
> 3/ Press: C-x 2
> 4/ Move your mouse to the corner of the frame, grab it, drag up,
> rescaling the vertically to minimum size

I tried this recipe with the *GTK+ build* compiled with
--enable-checking on Mac OS X 10.6.4, and I got the following
assertion failure:

.../src/xdisp.c:11515: Emacs fatal error: assertion failed: BUFFERP(w->buffer)

11511     /* If showing the region, and mark has changed, we must redisplay
11512        the whole window.  The assignment to this_line_start_pos prevents
11513        the optimization directly below this if-statement.  */
11514     if (((!NILP (Vtransient_mark_mode)
11515           && !NILP (XBUFFER (w->buffer)->mark_active))
11516          != !NILP (w->region_showing))
11517         || (!NILP (w->region_showing)
11518             && !EQ (w->region_showing,

The value of w->buffer was nil when the assertion failure occurred.

                                     YAMAMOTO Mitsuharu
                                mituharu@math.s.chiba-u.ac.jp