Comment 2 for bug 1578919

Crash appears to be in snapping. Error message:

inkscape: /usr/include/boost/optional/optional.hpp:1005: boost::optional<T>::reference_type boost::optional<T>::get() [with T = Geom::Rect; boost::optional<T>::reference_type = Geom::Rect&]: Assertion `this->is_initialized()' failed.

#0 0x00007fffeeb59a28 in raise () at /lib64/libc.so.6
#1 0x00007fffeeb5b62a in abort () at /lib64/libc.so.6
#2 0x00007fffeeb52227 in __assert_fail_base () at /lib64/libc.so.6
#3 0x00007fffeeb522d2 in () at /lib64/libc.so.6
#4 0x0000000000eb9bb2 in Geom::Sweeper<Geom::PathIntersectionSweepSet>::process() (this=<optimized out>) at /usr/include/boost/optional/optional.hpp:1005
#5 0x0000000000eb9bb2 in Geom::Sweeper<Geom::PathIntersectionSweepSet>::process() (this=<optimized out>) at /usr/include/boost/optional/optional.hpp:1022
#6 0x0000000000eb9bb2 in Geom::Sweeper<Geom::PathIntersectionSweepSet>::process() (ii=..., this=<optimized out>) at 2geom/pathvector.cpp:179
#7 0x0000000000eb9bb2 in Geom::Sweeper<Geom::PathIntersectionSweepSet>::process() (this=this@entry=0x7fffffffced0) at ./2geom/sweeper.h:115
#8 0x0000000000eb8676 in Geom::PathVector::intersect(Geom::PathVector const&, double) const (this=this@entry=0x7fffffffd050, other=..., precision=precision@entry=9.9999999999999995e-07)
    at 2geom/pathvector.cpp:228
#9 0x000000000074f738 in Inkscape::ObjectSnapper::_snapPathsConstrained(IntermSnapResults&, Inkscape::SnapCandidatePoint const&, Inkscape::Snapper::SnapConstraint const&, Geom::Point const&) const (this=this@entry=0x4765030, isr=..., p=..., c=..., p_proj_on_constraint=...) at object-snapper.cpp:647
#10 0x00000000007503dd in Inkscape::ObjectSnapper::constrainedSnap(IntermSnapResults&, Inkscape::SnapCandidatePoint const&, Geom::OptRect const&, Inkscape::Snapper::SnapConstraint const&, std::vector<SPItem const*, std::allocator<SPItem const*> > const*, std::vector<Inkscape::SnapCandidatePoint, std::allocator<Inkscape::SnapCandidatePoint> >*) const (this=0x4765030, isr=..., p=..., bbox_to_snap=..., c=..., it=0x47652a8, unselected_nodes=0x0) at object-snapper.cpp:734
#11 0x00000000007939da in SnapManager::multipleConstrainedSnaps(Inkscape::SnapCandidatePoint const&, std::vector<Inkscape::Snapper::SnapConstraint, std::allocator<Inkscape::Snapper::SnapConstraint> > const&, bool, Geom::OptRect const&) const (this=this@entry=0x4765018, p=..., constraints=std::vector of length 2, capacity 2 = {...}, dont_snap=dont_snap@entry=false, bbox_to_snap=...) at snap.cpp:344
#12 0x0000000000794cc4 in SnapManager::constrainedAngularSnap(Inkscape::SnapCandidatePoint const&, boost::optional<Geom::Point> const&, Geom::Point const&, unsigned int) const (this=this@entry=0x4765018, p=..., p_ref=..., o=..., snaps=snaps@entry=12) at snap.cpp:378
#13 0x0000000000cdc836 in Inkscape::UI::Tools::spdc_endpoint_snap_rotation(Inkscape::UI::Tools::ToolBase const*, Geom::Point&, Geom::Point const&, unsigned int) (ec=<optimized out>, p=..., o=..., state=<optimized out>) at ui/tools/freehand-base.cpp:586
#14 0x0000000000cfbecf in Inkscape::UI::Tools::PenTool::_endpointSnap(Geom::Point&, unsigned int) const (this=<optimized out>, p=..., state=<optimized out>) at ui/tools/pen-tool.cpp:270
#15 0x0000000000cfd86e in Inkscape::UI::Tools::PenTool::_handleMotionNotify(_GdkEventMotion const&) (this=0x34e92f0, mevent=...) at ui/tools/pen-tool.cpp:632
#16 0x0000000000cfde75 in Inkscape::UI::Tools::PenTool::root_handler(_GdkEvent*) (this=0x34e92f0, event=0x4ac8c80) at ui/tools/pen-tool.cpp:340
#17 0x0000000000d17fba in Inkscape::UI::Tools::sp_event_context_virtual_root_handler(Inkscape::UI::Tools::ToolBase*, _GdkEvent*) (event_context=event_context@entry=0x34e92f0, event=0x4ac8c80)
    at ui/tools/tool-base.cpp:1000
#18 0x0000000000d18059 in Inkscape::UI::Tools::sp_event_context_virtual_item_handler(Inkscape::UI::Tools::ToolBase*, SPItem*, _GdkEvent*) (event_context=event_context@entry=0x34e92f0, item=<optimized out>, event=<optimized out>) at ui/tools/tool-base.cpp:1050
#19 0x0000000000d1819e in Inkscape::UI::Tools::sp_event_context_snap_watchdog_callback(void*) (data=0x58c7ef0) at ui/tools/tool-base.cpp:1356
#20 0x00007fffefd128b3 in g_timeout_dispatch () at /lib64/libglib-2.0.so.0
#21 0x00007fffefd11e5a in g_main_context_dispatch () at /lib64/libglib-2.0.so.0
#22 0x00007fffefd121f0 in g_main_context_iterate.isra () at /lib64/libglib-2.0.so.0
#23 0x00007fffefd12512 in g_main_loop_run () at /lib64/libglib-2.0.so.0
#24 0x00007ffff4ae8e57 in gtk_main () at /lib64/libgtk-x11-2.0.so.0
#25 0x00000000006c9afd in sp_main_gui(int, char const**) (argc=1, argv=0x7fffffffdfd8) at main.cpp:1144
#26 0x00007fffeeb45580 in __libc_start_main () at /lib64/libc.so.6
#27 0x00000000006c6179 in _start ()