Paper: TnT player cannon not working on creative (working on survival)

[SimonGhoul]

What behaviour is expected:

place TNT and just go flying

What behaviour is observed:

There's no effect, the tnt doesn't even push me anywhere.

Steps/models to reproduce:

Make the tnt canon on creative with obsidian and redstone, a fence on the middle. Surround yourself on Tnt. Be on creative. Explode

Plugin list:

Server restorer https://www.spigotmc.org/resources/serverrestorer.48853/
WorldBorder
AutoRestart

Paper build number:

Paper-149
MC 1.14.4

Anything else:

Do you want my yml files? I did some edits found here https://www.spigotmc.org/threads/guide-server-optimization%E2%9A%A1.283181/ (and maybe some found here by accident, because I found it first https://www.spigotmc.org/threads/guide-optimizing-spigot-remove-lag-fix-tps-improve-performance.21726/). I did try disabling optimize explosions and no effect

Also, dream about cheese, for luck

[MiniDigger]

Can you provide a screenshot of the Cannon so the team can try to reproduce?

[SimonGhoul]

Sorry I was not notified. I also realized people don't call it a tnt cannon, it's actually a tnt player canon

I took screenshots and made a video

https://streamable.com/pucrn 3 minutes long, I try to do it in survival and creative (the video is being uploaded at the time I made this comment) edit: rip video, 3 month inactivity, should had done youtube

[SimonGhoul]

yo @MiniDigger you getting notified?
I don't get how github doesn't notify me, I am guessing this is a thing for everybody

[MiniDigger]

yes I am getting notified, but I can't help you. I was just making sure that the team has enough information to help you.

[SimonGhoul]

@MiniDigger alright I understand

[SimonGhoul]

Bump?

[Prof-Bloodstone]

Can confirm it doesn't happen on freshly built 1.16.1 Spigot git-Spigot-9639cf7-4b9bc9d, but does happen on Paper 1.16.1 build 138.

There was a similar issue in Spigot https://hub.spigotmc.org/jira/browse/SPIGOT-5258, which got since fixed: https://hub.spigotmc.org/stash/projects/SPIGOT/repos/craftbukkit/diff/nms-patches/EntityHuman.patch?until=b2bcde89d9267709f81fda53afa7cd3d7204c7b6

In Paper it looks like EntityPlayer.damageEntity method is not called at all for creative players for some reason - unfortunately wasn't able to find the root cause yet.

[Chew]

Looks like it is, unless I'm bad at reading:

https://github.com/PaperMC/Paper/blob/master/Spigot-Server-Patches/0033-Disable-explosion-knockback.patch#L18

I suppose the bug is by default it's false but still not working?

[Prof-Bloodstone]

This is not the patch that causes it. Completely removing this patch doesn't fix the issue.

The only patch I was expecting was the Cancelable entity death event, since it appears to be the only one messing with it directly, but removing it didn't fix the issue either.

[Prof-Bloodstone]

The problematic change is https://github.com/PaperMC/Paper/blob/master/Spigot-Server-Patches/0031-Fix-lag-from-explosions-processing-dead-entities.patch#L16 . Removing this patch fixed the issue.

This is caused by IEntitySelector.canAITarget().test(entity), where canAITarget() is:

!(entity instanceof EntityHuman) || !entity.isSpectator() && !((EntityHuman) entity).isCreative();

I don't see the reason this check is required, though there might be some important reason why - if you know it, I'd love to hear it. Working on a fix for it.

[SimonGhoul]

Thank you guys for working on this