Inkscape trunk crashes if a 'Pattern-along-path' LPE is applied to a path with a horizontal (straight) line segment (it makes no difference whether the horizontal segment is at the beginning, end or somewhere in-between other (slanted or curved) line segments of the path.
Steps to reproduce:
1) launch trunk (default new prefs, default new doc)
2) switch to the pen tool, select shape 'Ellipse'
3) draw a path with at least one horizontal straight line segment
--> Inkscape crashes as soon as the path is finished (e.g. with RMB click):
Program received signal EXC_BAD_ACCESS, Could not access memory.
Reason: KERN_INVALID_ADDRESS at address: 0x0000000000000000
0x000000010038865b in Geom::SBasis::operator[] (this=0x1180bfb70, i=0) at sbasis.h:79
79 return d[i];
Steps to reproduce:
1) launch trunk (default new prefs, default new doc)
2) switch to the star tool, draw a triangle (3 corners),
use 'Ctrl' so that base line is horizontal (drag vertically)
3) apply 'Pattern along Path' path effect
--> crash
First encountered with Inkscape 0.91+devel r14281 on OS X 10.7.5.
Based on tests with archived builds:
- not reproduced with 0.91+devel rev 14224,
- reproduced with 0.91+devel rev 14228;
this crash is likely related to the recent 2geom update in r14226:
https://bazaar.launchpad.net/~inkscape.dev/inkscape/trunk/revision/14226
Possibly related comment: Bug #1473317 comment 5
reproduced using the attached demo file. This was made using the first method above, pen tool with shape 'Ellipse'. Upon loading the file I get the attached backtrace.
Program received signal SIGSEGV, Segmentation fault.
0x00432832 in Geom::force_
(gdb) bt
#0 0x00432832 in Geom::force_
#1 0x00feb7cf in _Unwind_
at ../../.
#2 0x00000001 in ?? ()
#3 0x0023e1a8 in ?? ()