Projectiles shot at a Nether Portal appear behind it before disappearing to The Nether

So how exactly do arrows duplicate? Shot arrows go through portals - intended feature.

Yeah, it only duplicates through the portal from a dispenser.

Yeah, it only duplicates through the portal from a dispenser.

Cannot reproduce, I activate 2 dispensers at the same time, which shoot 2 arrows at the same time and go into the portal at the same time and if I follow I get 2 arrows on the other side.

It only reproduce in the real world for about 2 seconds then vanishes.Did you see it come at you?

I see, but this is pure graphical. Small lag while the arrows are loaded into the nether. You neither can pick up those arrows nor do they hurt you.

Oh lol so it just a really small graphic glitch and that's all?

From my tests indeed.

Ok thank you for notifying me.

Cameron, if you don't want to publicly show your email adress , you should better edit your comments in this ticket - and when replying via email at least remove the quoted part...

Is this still a concern in the current Minecraft version? If so, please update the affected versions in order to best aid Mojang ensuring bugs are still valid in the latest releases/pre-releases.

Still in 1.7.2. The arrows only appear behind the portal for a split second though.

Confirmed for

• 14w30c

• 14w31a

• Minecraft 1.8-pre 1

Confirmed for

• 15w37a

Note to tests in recent versions: Due to another bug, arrows don't get teleported at all. It's still possible to test this bug by standing near the portal while shooting. About 2-3 blocks distance is the limit.

It seems that in 16w32a, arrows get "stuck" on the portal as if it's a solid block. Then they disappear and get teleported.

Confirmed for 1.13.1.

In 1.16 Pre-release 2, arrows and tridents go through the portal, without teleporting - as if it was air.

Can confirm in 20w51a.

Can confirm in 21w05b.

I can confirm in 21w07a.

Can confirm in 21w42a.

This is why it happens:

In Minecraft 1.16.1 and earlier versions, thrown projects checks if the OUTLINE shapes of blocks, to find potential collisions and chances to be teleported ("hit" a nether_portal block, for example)(See ThrowableProjectile.tick()). A portal has its non-empty OUTLINE shapes though it has no collision box which can stop regular entity movement, so thrown projectiles can always detect if it can be teleported no matter how high their velocity is.

But in 1.16.2-pre1, something was changed. The  OUTLINE shape get no longer used in collision checks, instead, the COLLIDER shape has been used since then (See ThrowableProjectile.tick() &  ProjectileUtil.getHitResult()). However, portals has empty COLLIDER shapes, so the teleporting check became dead code. And entities only stays in some seperated points, thus if the velocity of a thrown projectile entity is greater than 1 bloch per tick, it may pass through the portal if it failed to be teleported in the Entity.handleNetherPortal() method.

Suggestions to solve it:

The change may be intended to fix MC-73844, simply changing it back is not a good idea. But a addional ray trace may be introduced when the speed of the entity is higher than 1 block pre tick, just like what falling_blocks of concrete powder do.