Intro:

First seen on the BlameJared Discord, a user of CraftTweaker was seeing an NPE triggered by a script. On tracking it down, it came back to a pair of non-existent items.

Issue Description:

CraftTweaker will crash with a NullPointerError if a non-existent item is referenced in a call to recipes.remove()

What happens:

At line 618 of crafttwaker.mc1120.recipes.MCRecipeManager there are insufficient checks for stack validity, leading to an attempt to dereference a Null Pointer in a called method at line 630 of the same file.

This triggers a classic Java Null Pointer Exception and crash.

What you expected to happen:

Safeguards to ignore the null/nonexistent item and continue processing, with a log-message recording the issue.

Script used (Please Pastebin or gist your script, posting an unpasted or ungist'd script will automatically close this issue):

Any reference to a nonexistent item, such as recipes.remove(<projecte:rm_furnace_lit>);

crafttweaker.log file (Please Pastebin or gist your file, posting an unpasted or ungist'd file will automatically close this issue):

Unavailable at this time

Affected Versions (Do not use "latest"):

• Minecraft: 1.12.0
• Forge: 14.23.5.2837
• Crafttweaker: 4.1.18
• Using a server: Not for a confirmation test, should still apply
• If yes, does the client have the exact same scripts?

Your most recent log file where the issue was present:

pastebin link here

If you provide an invalid Item BH, then /ct syntax will already tell you that you have errors in your script.
It is true that we might have to add a check there but generally, you shouldn't even try to run your scripts if they error on you beforehand.

yeah, person that showed up on Discord doesn't seem to have done that and couldn't even get into the game because of the crash... Found it by actually trying a /give of the items in the block they'd managed to track the issue down to.