git for-each-ref crashes for %(body) with tags

Hi,

see gdb trace below.   Unfortunately, I don't have a repo that I can
readily share to demonstrate this.

(gdb) r for-each-ref --format '%(body)' refs/tags
..

Breakpoint 1, grab_sub_body_contents (val=<value optimized out>,
deref=0, obj=<value optimized out>, buf=0x8146ad0, sz=161)
    at builtin-for-each-ref.c:494
494                             v->s = xstrdup(bodypos);
(gdb) p bodypos
$10 = 0x0

(gdb) n
496                             v->s = xstrdup(subpos);
(gdb) n

Program received signal SIGSEGV, Segmentation fault.
0x4d9ff013 in strlen () from /lib/tls/i686/cmov/libc.so.6

-- 
Han-Wen Nienhuys - hanwen@xs4all.nl - http://www.xs4all.nl/~hanwen