[Dot] dot crash using rank

[GadgetSteve]

Ported Issue from Mantis
Original ID: 1226
Reported By: Mathieu Virbel

SEVERITY: CRITICAL
Submitted: 2007-12-28 10:31:58

OS: X86-LINUX-UBUNTU GUSTY

VERSION: 2.12

DESCRIPTION

I've a crash using rank=same with a subgraph (not include in rank).

I've used this line :
dot -v -Tpng test.dot > test.png

Here is the output :

The plugin configuration file:
/usr/lib/graphviz/config3
was successfully loaded.
render : canon cmap cmapx dia dot fig gd gd2 gif gtk hpgl imap ismap jpeg jpg mif mp pcl pdf pic plain plain-ext png ps ps2 svg svgz vrml vtx wbmp xdot xlib
layout : circo dot fdp neato nop nop1 nop2 twopi
textlayout : textlayout
device : xlib
loadimage : 2ps gif2fig gif2gd gif2ps gif2svg gif2vrml jpeg2fig jpeg2gd jpeg2ps jpeg2svg jpeg2vrml png2cairo png2fig png2gd png2ps png2svg png2vrml ps2ps
dot: fontname "Times-Roman" resolved to "Nimbus Roman No9 L, regular"
network simplex: 2 nodes 1 edges 0 iter 0.00 sec
Warning: C was already in a rankset, ignored in cluster G
network simplex: 3 nodes 2 edges 0 iter 0.00 sec
Erreur de segmentation (core dumped)

And the gdb trace :

0xb78c6fd6 in build_skeleton () from /usr/lib/graphviz/libgvplugin_dot_layout.so.3
(gdb) bt
#0 0xb78c6fd6 in build_skeleton () from /usr/lib/graphviz/libgvplugin_dot_layout.so.3
#1 0xb78c654a in class2 () from /usr/lib/graphviz/libgvplugin_dot_layout.so.3
#2 0xb78ce7df in dot_mincross () from /usr/lib/graphviz/libgvplugin_dot_layout.so.3
#3 0xb78cbd3e in dot_layout () from /usr/lib/graphviz/libgvplugin_dot_layout.so.3
#4 0xb7eb50ea in gvLayoutJobs () from /usr/lib/libgvc.so.3
#5 0x08048982 in ?? ()
#6 0x0804b7c8 in ?? ()
#7 0x08055100 in ?? ()
#8 0xbfdacd44 in ?? ()
#9 0x00000000 in ?? ()

## STEPS TO REPRODUCE

digraph G {
A -> C;

subgraph cluster_0 {
    F -> C;
}

{rank=same; A C}

}