Expected: Calling BlockMultipart::getPickBlock in a manner identical to vanilla produces the same result as if the block were picked.
Observed: Client crashes.
Known Workarounds: Crash is only known to occur in interactions with specific mods, so removing either FMP or the mod it's interacting with is sufficient to stop the problem.
The reduceMOP function in BlockMultipart blindly assumes that the MovingObjectPosition is an ExtendedMOP. This is a bad assumption.
We got word of the problem originally over here: https://github.com/elytra/FruitPhone/issues/13
Expected: Calling BlockMultipart::getPickBlock in a manner identical to vanilla produces the same result as if the block were picked.
Observed: Client crashes.
Known Workarounds: Crash is only known to occur in interactions with specific mods, so removing either FMP or the mod it's interacting with is sufficient to stop the problem.