Creating a custom biome world crashes the game

So I'm trying to learn how to make a custom biome. I found a few examples and tested them and they were perfectly fine. But when I created my own one and run the game with the selected biome, the game crashes. it doesn't close it self. it just doesn't respond to anything and a few seconds later the program not responding dialog pops up.

also when the game is trying to join the world the console is full of this log:

[12:47:01] [Render thread/WARN]: Received invalid biome id: -1

The log file, datapack, world is included in the attachments.

I'm not sure if this is a bug or not but someone told me when the game crashes it's always a bug.