Blocks with hardness set to 0 never really break, and doesn't drop.

[jimmikaelkael]

All blocks with a value of 0 as Hardness never breaks on the server, it breaks on client side but not on server. As a result all drops never get dropped.

I can take a few examples:

• Tall grass never drops seeds
• Pumpkin and melon stems never drop seeds.
• Torches never drop.

[turt2live]

According to #629, DiggingHandler.handle doesn't call DiggingMessage.FINISH_DIGGING for these blocks.