I coded some custom loot tables for mobs in 1.11.2 to allow for the drop of their spawn eggs. Jumped over to 1.12 and I get a new error that does not allow for mob identification in the following line:
Original code: "tag":"{EntityTag:{id:minecraft:creeper}}"}
It gives the following error:
Expected '}' but got ':' at: {EntityTag:{id:minecraft:<--[HERE]
Attached is my .json file for a creeper to drop it's spawn egg along with it's mob head, but this error happens to all altered loot tables regarding the drop of mob eggs.
This is intended (see http://minecraft.gamepedia.com/1.12, section NBT format): Just put quotes around the id