bug#11541: 24.0.97; Crash when visiting file on OS X 10.7.3

[Eli Zaretskii]

> From: "C. Florian Ebeling" <florian.ebeling@gmail.com>
> Date: Thu, 31 May 2012 21:50:21 +0200
> Cc: cyd@gnu.org,
>  11541@debbugs.gnu.org
> 
> Yes, I understand. My problem is that I don't know what to look for, 
> honestly. I haven't used the NSFontDescriptor API much and I don't know the 
> first thing about Emacs internals. The slowness or tedium is not my biggest 
> worry.

The code involved in this hardly ever touches Emacs internals.  It's
simple ObjC code, at least to my naive eyes.

As the first goal, I suggest to try figuring out what happens with the
font_spec argument to ns_findfonts -- is it corrupted right at entry
to the function, or does it get corrupted later?  You should display
it, using the same commands you used for scratch_font_spec in its
caller, right at the entry to the function.  Assuming the value at
entry is OK (which would be my guess), then step through the code of
ns_findfonts, and see which line causes its corruption.

When we know where the corruption happens, we could reason about what
to try next.

TIA