Affects Version/s: Minecraft 13w37a, Minecraft 13w37b, Minecraft 13w38b, Minecraft 13w38c, Minecraft 13w39a, Minecraft 13w41b, Minecraft 13w42a, Minecraft 13w42b, Minecraft 13w43a, Minecraft 1.7
Fix Version/s: Minecraft 1.7.1
When the game encounters an unrecognized or "invalid" item ID, it reacts by crashing and often deleting the chunk which contained the item. Invalid item IDs can be created in a number of ways, including breaking lit redstone lamps with a Silk Touch enchantment, or loading a world from a version where these IDs are considered valid.
Steps to Reproduce:
1. Place a redstone lamp, and power it.
2. In survival, break the lamp with a Silk Touch tool.
3. Observe that the game crashes, and when you reload the world, the chunk will be regenerated (all player-made structures removed, and all mined ores respawned).
Alternate Steps to Reproduce:
1. Load up a world in Minecraft 1.6.2.
2. Type "/give @p 75" (you must have Cheats enabled)
3. Observe that you are given an unlit redstone torch. It seems to work perfectly fine as an item when held, placed in a chest, mounted in an item frame, or placed as a block. No crashes occur.
4. Place the torch in a chest, and save/exit the world.
5. Load the world in 13w37a.
6. Observe that the entire chunk containing the chest has been refreshed.