[Dot] 91-line input file with edge label segfaults dot 2.12 on gentoo

[GadgetSteve]

Ported Issue from Mantis
Original ID: 771
Reported By: default_357-line

SEVERITY: MAJOR
Submitted: 2007-08-30 13:09:12

OS: OTHER-LINUX-LINUX 2.6.22-KAMIKAZ

VERSION: 2.12

DESCRIPTION

The dot input causes the following error (in gdb):
Program received signal SIGSEGV, Segmentation fault.

0x00002ad9d9457fc0 in ?? () from /usr/lib64/graphviz/libgvplugin_dot_layout.so.3
(gdb) bt
#0 0x00002ad9d9457fc0 in ?? () from /usr/lib64/graphviz/libgvplugin_dot_layout.so.3
#1 0x00002ad9d94582ba in dot_concentrate () from /usr/lib64/graphviz/libgvplugin_dot_layout.so.3
#2 0x00002ad9d945f180 in dot_position () from /usr/lib64/graphviz/libgvplugin_dot_layout.so.3
#3 0x00002ad9d945a01d in dot_layout () from /usr/lib64/graphviz/libgvplugin_dot_layout.so.3
#4 0x00002ad9d6dc7b76 in gvLayoutJobs () from /usr/lib/libgvc.so.3
#5 0x0000000000400bfd in ?? ()
#6 0x00002ad9d77e9323 in __libc_start_main () from /lib/libc.so.6
#7 0x0000000000400ad9 in ?? ()
#8 0x00007fffd3e1dcc8 in ?? ()
#9 0x0000000000000000 in ?? ()

(gdb)

STEPS TO REPRODUCE

Digraph G {
graph [concentrate=true, ];
subgraph cluster_A {
"X";
}
subgraph cluster_B {
"Y";
"Z";
}
"X" -> "K" [weight=4.36794];
"Z" -> "K" [weight=1.76549, label=" "];
"Z" -> "Y"[weight=3.53098];
"Y" -> "L"[weight=2.46349];
"M" -> "L"[weight=2.71826];
"M" -> "X";
}

ADDITIONAL INFORMATION

[ryan] Regarding bug 1182, I can confirm that the given graph does also crash dot from graphviz 2.15.20070926.0438 on Mac OS X 10.4.10 Intel:

Exception: EXC_BAD_ACCESS (0x0001) Codes: KERN_PROTECTION_FAILURE (0x0002) at 0x000000d8

Thread 0:
0 libgvplugin_dot_layout.5.dylib 0x007cf08c rebuild_vlists + 374
1 libgvplugin_dot_layout.5.dylib 0x007cf5c6 dot_concentrate + 771
2 libgvplugin_dot_layout.5.dylib 0x007dd246 dot_position + 77
3 libgvplugin_dot_layout.5.dylib 0x007d0190 dot_layout + 75
4 libgvc.4.dylib 0x0006cdce gvLayoutJobs + 143
5 dot 0x00001ee3 main + 331
6 dot 0x00001c22 _start + 216
7 dot 0x00001b49 start + 41

[ellson]This bug appears to be triggered by the blank label string 'label=" "'
Remove that attribute and the SIGSEGV doesn't happen.