Path Effects > Knot crashes Inkscape selecting Nodes tool

[FirasH]

- Steps to reproduce:

0) Create a new document
1) Insert a Rectangle or Circle
2) Go to: Path > Path Effects ...
3) Add "Knot" Path Effect
4) Click on the tool to edit nodes (F2)

Inkscape crashes

- System information:

Inkscape version: 0.91pre2 r13536
OS: openSUSE 13.1 (x86_64)

[su_v (suv-lp)]

Reproduced with 0.91pre2 r13536 on OS X 10.7.5.

Based on tests with archived builds:
- not reproduced with rev <= 13485
- reproduced with rev >= 13488
this regression appears to have be related to the changes in
Revision 13487: Fix for #906794, #1246550 (live effects not showing helper paths)
<http://bazaar.launchpad.net/~inkscape.dev/inkscape/trunk/revision/13487>

[su_v (suv-lp)]

Not much info in the normal backtrace ...

(inkscape:93210): glibmm-ERROR **:
unhandled exception (type std::exception) in signal handler:
what: lib2geom exception: Non-contiguous path (../../src/2geom/path.cpp:91)

Program received signal SIGTRAP, Trace/breakpoint trap.
0x00000001052300d8 in _g_log_abort ()

[su_v (suv-lp)]

Better backtrace (thx to LiamW)

[su_v (suv-lp)]

Test case:
- path self-intersecting: ok
- path not self-intersecting: crash

[Liam P. White (liampwhite)]

Fix committed in lp:inkscape r13537

[FirasH (firashanife)]

The crash is not reproducible with 0.91pre2 r13537.