_mapnik_shield_symbolizer.rb:141: [BUG] Segmentation fault
ruby 1.8.7 (2010-01-10 patchlevel 249) [universal-darwin11.0]
Thread 0 Crashed:: Dispatch queue: com.apple.main-thread
0 libsystem_kernel.dylib 0x00007fff8a07082a __kill + 10
1 libsystem_c.dylib 0x00007fff88f5da9c abort + 177
2 libruby.1.dylib 0x0000000101df3649 rb_bug + 316
3 libruby.1.dylib 0x0000000101e5ad8c 0x101de0000 + 503180
4 libsystem_c.dylib 0x00007fff88fbecfa _sigtramp + 26
5 libmapnik.dylib 0x000000010264acb5 mapnik::to_expression_string(boost::variant<mapnik::value, mapnik::attribute, boost::recursive_wrapper<mapnik::binary_node<mapnik::tags::plus> >, boost::recursive_wrapper<mapnik::binary_node<mapnik::tags::minus> >, boost::recursive_wrapper<mapnik::binary_node<mapnik::tags::mult> >, boost::recursive_wrapper<mapnik::binary_node<mapnik::tags::div> >, boost::recursive_wrapper<mapnik::binary_node<mapnik::tags::mod> >, boost::recursive_wrapper<mapnik::binary_node<mapnik::tags::less> >, boost::recursive_wrapper<mapnik::binary_node<mapnik::tags::less_equal> >, boost::recursive_wrapper<mapnik::binary_node<mapnik::tags::greater> >, boost::recursive_wrapper<mapnik::binary_node<mapnik::tags::greater_equal> >, boost::recursive_wrapper<mapnik::binary_node<mapnik::tags::equal_to> >, boost::recursive_wrapper<mapnik::binary_node<mapnik::tags::not_equal_to> >, boost::recursive_wrapper<mapnik::unary_node<mapnik::tags::logical_not> >, boost::recursive_wrapper<mapnik::binary_node<mapnik::tags::logical_and> >, boost::recursive_wrapper<mapnik::binary_node<mapnik::tags::logical_or> >, boost::recursive_wrapper<mapnik::regex_match_node>, boost::recursive_wrapper<mapnik::regex_replace_node>, boost::detail::variant::void_, boost::detail::variant::void_> const&) + 37
6 ruby_mapnik.bundle 0x00000001021d7114 (anonymous namespace)::expr_node_to_string_(boost::shared_ptr<boost::variant<mapnik::value, mapnik::attribute, boost::recursive_wrapper<mapnik::binary_node<mapnik::tags::plus> >, boost::recursive_wrapper<mapnik::binary_node<mapnik::tags::minus> >, boost::recursive_wrapper<mapnik::binary_node<mapnik::tags::mult> >, boost::recursive_wrapper<mapnik::binary_node<mapnik::tags::div> >, boost::recursive_wrapper<mapnik::binary_node<mapnik::tags::mod> >, boost::recursive_wrapper<mapnik::binary_node<mapnik::tags::less> >, boost::recursive_wrapper<mapnik::binary_node<mapnik::tags::less_equal> >, boost::recursive_wrapper<mapnik::binary_node<mapnik::tags::greater> >, boost::recursive_wrapper<mapnik::binary_node<mapnik::tags::greater_equal> >, boost::recursive_wrapper<mapnik::binary_node<mapnik::tags::equal_to> >, boost::recursive_wrapper<mapnik::binary_node<mapnik::tags::not_equal_to> >, boost::recursive_wrapper<mapnik::unary_node<mapnik::tags::logical_not> >, boost::recursive_wrapper<mapnik::binary_node<mapnik::tags::logical_and> >, boost::recursive_wrapper<mapnik::binary_node<mapnik::tags::logical_or> >, boost::recursive_wrapper<mapnik::regex_match_node>, boost::recursive_wrapper<mapnik::regex_replace_node>, boost::detail::variant::void_, boost::detail::variant::void_> >) + 20 (_mapnik_expression.rb.cpp:45)
7 ruby_mapnik.bundle 0x00000001021d976d Rice::detail::Auto_Function_Wrapper<std::string (*)(boost::shared_ptr<boost::variant<mapnik::value, mapnik::attribute, boost::recursive_wrapper<mapnik::binary_node<mapnik::tags::plus> >, boost::recursive_wrapper<mapnik::binary_node<mapnik::tags::minus> >, boost::recursive_wrapper<mapnik::binary_node<mapnik::tags::mult> >, boost::recursive_wrapper<mapnik::binary_node<mapnik::tags::div> >, boost::recursive_wrapper<mapnik::binary_node<mapnik::tags::mod> >, boost::recursive_wrapper<mapnik::binary_node<mapnik::tags::less> >, boost::recursive_wrapper<mapnik::binary_node<mapnik::tags::less_equal> >, boost::recursive_wrapper<mapnik::binary_node<mapnik::tags::greater> >, boost::recursive_wrapper<mapnik::binary_node<mapnik::tags::greater_equal> >, boost::recursive_wrapper<mapnik::binary_node<mapnik::tags::equal_to> >, boost::recursive_wrapper<mapnik::binary_node<mapnik::tags::not_equal_to> >, boost::recursive_wrapper<mapnik::unary_node<mapnik::tags::logical_not> >, boost::recursive_wrapper<mapnik::binary_node<mapnik::tags::logical_and> >, boost::recursive_wrapper<mapnik::binary_node<mapnik::tags::logical_or> >, boost::recursive_wrapper<mapnik::regex_match_node>, boost::recursive_wrapper<mapnik::regex_replace_node>, boost::detail::variant::void_, boost::detail::variant::void_> >), std::string, boost::shared_ptr<boost::variant<mapnik::value, mapnik::attribute, boost::recursive_wrapper<mapnik::binary_node<mapnik::tags::plus> >, boost::recursive_wrapper<mapnik::binary_node<mapnik::tags::minus> >, boost::recursive_wrapper<mapnik::binary_node<mapnik::tags::mult> >, boost::recursive_wrapper<mapnik::binary_node<mapnik::tags::div> >, boost::recursive_wrapper<mapnik::binary_node<mapnik::tags::mod> >, boost::recursive_wrapper<mapnik::binary_node<mapnik::tags::less> >, boost::recursive_wrapper<mapnik::binary_node<mapnik::tags::less_equal> >, boost::recursive_wrapper<mapnik::binary_node<mapnik::tags::greater> >, boost::recursive_wrapper<mapnik::binary_node<mapnik::tags::greater_equal> >, boost::recursive_wrapper<mapnik::binary_node<mapnik::tags::equal_to> >, boost::recursive_wrapper<mapnik::binary_node<mapnik::tags::not_equal_to> >, boost::recursive_wrapper<mapnik::unary_node<mapnik::tags::logical_not> >, boost::recursive_wrapper<mapnik::binary_node<mapnik::tags::logical_and> >, boost::recursive_wrapper<mapnik::binary_node<mapnik::tags::logical_or> >, boost::recursive_wrapper<mapnik::regex_match_node>, boost::recursive_wrapper<mapnik::regex_replace_node>, boost::detail::variant::void_, boost::detail::variant::void_> >, void, void, void, void, void, void, void, void, void, void, void, void, void, void, void>::call(int, unsigned long*, unsigned long) + 365 (basic_string.h:279)