I wrote a command who should give me an item, then Minecraft crashed. Now I can't open the world anymore.

Put the summary of the bug you're having here

What I expected to happen was that the command gives me an item with special attributes
Describe what you thought should happen here

What actually happened was that Minecraft crashed
Describe what happened here

Steps to Reproduce:
1. Put a step by step guide on how to trigger the bug here
2. ...
3. ...