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Minecraft version: 1.12.2 [change as necessary]
Wizardry version: 4.3.1 [change as necessary]
Environment: Client Side when updating lighting and chunks

Issue details: When I right click to throw one of these bomb projectiles, it does not spawn, and Vanilla Fix shoots out the following crash log.

Other mods involved: Thoroughly tested, is an actual issue with Wizardry itself.

Link to crash report (if applicable):
crash-2020-11-19_13.16.31-server.txt

There is no client crash log. It only shows a server side crash.

And I swear I remember this lighting "animation" effect when the bomb explodes. But I guess that was some weird dream I had...

You could try turning off dynamic lights for entities in Optifine and see if that makes a difference. Other than that, please try removing mods one by one until the issue disappears, so I can narrow down which mod is causing the problem.

Did you try either of these? They will help me to narrow down the cause of the problem.

I've tested this and it does not happen in my installation with any of the throwables. Same version, singleplayer world, survival or creative. Can you confirm that this happens with no other mods installed? Even when crash reports look like they only involve one mod, it doesn't mean others weren't involved.

JEI...Optifine...

I can confirm yet again, that at least with Wizardry and Optifine installed, it crashes.

This is probably due to the fact you are forcing the bomb to add light to chunks. can you add a configuration to disable this custom lighting code so optifine behaves with it?

This is probably due to the fact you are forcing the bomb to add light to chunks. can you add a configuration to disable this custom lighting code so optifine behaves with it?

I am doing no such thing. Besides, the original crash you posted is server-side. Please post the new crash so I can check it is the same.

I don't know how much you know about Java, but here's a technical explanation of what's going on:

The crash is happening because the thrower is somehow null in vanilla's method for aiming the entity. However, if you follow the call stack back up you'll see that if it was null in my code, it would have crashed there before it ever got to vanilla code. The only possible explanation is that another mod has used ASM to mess with the vanilla method EntityThrowable#shoot and set the thrower to null before it gets aimed. Why any mod would do that is beyond me, but as usual Optifine is a suspect.

You could try turning off dynamic lights for entities in Optifine and see if that makes a difference. Other than that, please try removing mods one by one until the issue disappears, so I can narrow down which mod is causing the problem.