Seg Fault in #load about msgpack-ruby

[casperisfine]

Thanks, I'm able to repro and I'll dig into this.

[casperisfine]

Ok, so the bug is here:

frame #3: 0x0000000101cf190c msgpack.bundle`object_complete_ext(uk=0x0000600003e15200, ext_type=0, str=8) at unpacker.c:180:43
   177 	static inline int object_complete_ext(msgpack_unpacker_t* uk, int ext_type, VALUE str)
   178 	{
   179 	    if (uk->optimized_symbol_ext_type && ext_type == uk->symbol_ext_type) {
-> 180 	        return object_complete_symbol(uk, rb_str_intern(str));
   181 	    }
   182 	
   183 	    int ext_flags;

str=8 means str is nil. I think there is a logic bug because extension strings can be nil and we don't deal with that.

[casperisfine]

Test case reduced to:

require 'msgpack'
codec = MessagePack::Factory.new
type_attributes = {
  code: 0,
  packer: Symbol.method_defined?(:name) ? :name.to_proc : :to_s.to_proc,
  unpacker: :to_sym.to_proc,
  optimized_symbols_parsing: true,
}
codec.register_type(
  type_attributes.fetch(:code),
  Symbol,
  type_attributes
)

pp codec.load(codec.dump(:"")) # This should give the seg fault.