bug#7952: 24.0.50; crash in find_interval

[Romain Francoise <romain@orebokech.com>]

Hi Eli,

Thanks for your help.

Eli Zaretskii <eliz@gnu.org> writes:

> Can you show the value of relative_position and of TOTAL_LENGTH
> (tree)?

As you can see from the backtrace in my original report, tree is
NULL when `find_interval' is called, so TOTAL_LENGTH(tree) is 0.

(gdb) f 5
#5  0x00000000006612b8 in find_interval (tree=0x0, position=1626800)
    at intervals.c:635
635         abort ();                   /* Paranoia */
(gdb) p relative_position
$1 = 1626799
(gdb) p tree
$2 = (INTERVAL) 0x0
(gdb) p position
$3 = 1626800
(gdb)

> Perhaps I didn't move around enough -- does it take you a lot?

It's usually enough to do M-> and M-v, but sometimes it takes a
little more moving around to get it to crash (but it never takes
more than a few seconds).