The bug
Slimes and magma cubes do not jump higher with the Jump Boost effect, although it still reduces fall damage for Slimes.
Steps to reproduce
Spawn Slime
Run command
/effect give @e[type=slime] minecraft:jump_boost 60 10 false
Now you should see the particle effect, but the slime doesn't jump higher than normal.
For example see attached video or http://youtu.be/Upb30KUOVCM
Code analysis
Code analysis can be found in this comment.
Linked issues
is duplicated by 3
relates to 4
Attachments
Comments 40
Confirmed
Confirmed for 14w08a and 14w10c
Is this still a concern in the current Minecraft version 14w32d / Launcher version 1.5.2 or later? If so, please update the affected versions in order to best aid Mojang ensuring bugs are still valid in the latest releases/pre-releases.
Tested it in 14w34d. Slimes still don't jump higher with Jump boost effect applied.
Confirmed in 1.8-pre2 with Jump Boost II potion. Magma cubes are affected by this also.
Confirmed for 15w39c
Confirmed for 15w40a
Confirmed for 15w41b
Confirmed for 15w42a
Confirmed for 15w43a
Possibly intended (though I really hope not). Relates to MC-68331.
Also, please update the description to mention that this also occurs with Magma Cubes.
Confirmed for 15w44a
Confirmed for 1.9.2
Confirmed for 1.9.3-pre2
Confirmed for 1.12-pre2.
Confirmed for 1.12.2
Is already marked as affected.
Also Applies to education edition
versions 1.7.1 and 1.8.0
Please report that in the MCPE project. And reply back here so that it can get marked as related.
Confirmed in 19w45b.
I assume this is not a bug. Slimes and Magma cubes do not actually jump; they bounce up and down sort of like a player bouncing on a slime block.
Updated command:/effect give @e[type=slime] minecraft:jump_boost 60 10 false
Can confirm in 20w48a.
Can confirm in 20w51a.
Can confirm in 21w03a.
Can confirm in 21w05b.
Can confirm in 21w06a.
I've attached an updated video as the previous one is heavily outdated.
Can confirm in 21w07a.
Can confirm in 21w11a.
Can confirm in 21w14a.
Can confirm in 21w17a.
Can confirm in 1.17.
Can confirm in 1.17.1.
Can confirm in 1.18.1.
Can confirm in 1.18.2 and 22w11a.
Can confirm in 1.19.
Can confirm in 1.19.2.
Code analysis (Mojang mappings, 1.19.2): the code for checking the Jump Boost effect is in LivingEntity#jumpFromGround(), which slimes (and magma cubes) override in their respective classes. In Slime#jumpFromGround(), instead of
Vec3 $$0 = this.getDeltaMovement();
this.setDeltaMovement($$0.x, this.getJumpPower(), $$0.z);it should be
Vec3 $$0 = this.getDeltaMovement();
this.setDeltaMovement($$0.x, this.getJumpPower() + this.getJumpBoostPower(), $$0.z);For magma cubes, it is a bit more complicated, because I am unsure if the jump boost should be scaled with the magma cube's size or not. But it should be an analogous fix.
elvendorke
I really hope this gets fixed, I need it for my map...