Crash caused by null stack in BottomlessItemHandler

[cakeGit]

Describe the Bug

Related to #1036, and I think this is now causing an issue with saving on trains for creative crates,

Since the item is null but the save code iterates over it anyways, and this causes a crash here:

So it should be fine to just add a check for stack being null and the crash will be avoided

Reproduction Steps

1.Build a train
2.Put a creative crate on the train
3.Open the pause menu to trigger a save or close the game

Expected Result

Not to crash

Screenshots and Videos

Note that this is from a development environment, but the issue still happens outside
latest.log
crash-2024-08-01_23.21.16-server.txt

Crash Report or Log

https://github.com/user-attachments/files/16462392/crash-2024-08-01_23.21.16-server.txt

Operating System

Windows 11

Mod Version

0.5.1f

Minecraft Version

1.20.1

Other Mods

No response

Additional Context

No response

[TropheusJ]

Can't reproduce.
The stack should never ever be null, something else is wrong.
More debugging would be appreciated.

[cakeGit]

Ive gone back onto a backup of the world with the same everything and now i cant reproduce either :/
Ill look out for it in the future but it may have just been a fluke or some other issue at the same time.
My only thought is if its a missing mapping causing the item to become null after the tag has been read, but with testing this doesent work either, thanks for your time though,