On my snapshot world, I built a sugar cane farm controlled with redstone. I got a bit suspicious when nothing went into the hoppers or the chest, but let it slide. Over and over the sugar cane would grow and get pushed by the pistons but not drop anything, so I switched to survival and tried breaking it by hand and it didn't drop anything. DOES NOT CRASH!!!
Environment
OS: Windows 7 Home Premium
Java: 1.7.0_09
Playing: Singleplayer and LAN server
Players: 1 and 2
World Type: Classic Flat
Gamemode: Creative and Survival
Cheats: On
Version: 13w03a
Duplicate of MC-7622.