When pushing messages downtream we are not casting to the correct type

[DonAurelio]

cast_func = @cast_type ? "(#{self.class.instance_variable_get(:@bt_type)})" : '' is a dead line.

https://github.com/TApplencourt/metababel/blob/5999e715532185974ae334607c82f85a02c20a14/lib/metababel/bt2_trace_class_generator.rb#L444-L450

Possible solution

• We need to fix this to cast to @cast_type, not @bt_type.
• In addition, we need to add the special case for struct to const char * (string).

[DonAurelio]

Okay, I just realized that we can't cast to the @cast_type in get_setter since the user could cast to a non-babeltrace type, then we won't be able to set the field. We just need to remove the dead line.

[TApplencourt]

Yes, push message are more complicated. In theory, we should have the cast_type as input, and the cast to bt_type when calling the function. For struct -> string , we should do the memcopy trick