Spongeapi: StateMatcher can't be created without any traits

[Katrix]

BlockState.StateMatcher doesn't check if the traits for the StateMatcher is empty. Found this while writing a config serializer and deserializer for StateMatcher.

The fix should be trivial.
https://github.com/SpongePowered/SpongeAPI/blob/a4aaeec0007ebd9c3570e41382454e81f875e0a1/src/main/java/org/spongepowered/api/block/BlockState.java#L289

[Minecrell]

For me it looks like the actual problem is that it is creating the array with one element less than required, it should just create the array using this.traits.size().

[Katrix]

Guess I looked too long at it :P. Would it also be an idea to expose the inner fields in the matcher to allow for easier serialization (have to use reflection at the moment)?

[Minecrell]

You can open an issue about that. If anything, we could consider making it DataSerializable since that is how we expose serialization.