When drinking a potion, witches are given an attribute modifier that affects generic.movementSpeed with a value of -0.25 and an Operation of 0. As Witches' default value for generic.movementSpeed is 0.25, this effectively sets their generic.movementSpeed to 0. However, if a Witch is summoned with a custom generic.movementSpeed value over 0.25, it will be able to move while drinking a potion. If the custom value is under 0.25, then the witch will be able to move whilst under a slowness effect with amplifier 7 or greater, as 7 gives -105% movement speed. At negative movement speeds, that will become a positive movement speed.
The fix for these strange cases is to just make the attribute modifier for drinking potions be -1 with Operation 2, as this will set the witch's generic.movementSpeed attribute to 0, even if it has drunk a speed potion.
Steps To Reproduce: (from @unknown)
Run the command
/summon witch ~ ~ ~ {Attributes:[{Name:"generic.movement_speed",Base: 1.0d}]}Shoot the witch with a Flame bow.
Observe how the witch still moves while drinking a Fire Resistance potion.
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Why are you asking me? Why are you making me go check something that takes all of 2 seconds instead of doing it yourself while you're already here? Why are you sidelining this issue until I eventually find time to check my email?
YES, it is still an issue in 1.13.2. This is the kind of bug that requires a very intentional fix anyways, so I would be very surprised if it was accidentally fixed without being marked as fixed in a snapshot/pre-release.
Can confirm in 1.17.1. To reproduce:
1. Run the command
/summon witch ~ ~ ~ {Attributes:[{Name:"generic.movement_speed",Base: 1.0d}]}2. Shoot the witch with a Flame bow.
3. ❌ Observe how the witch still moves while drinking a Fire Resistance potion.
I can confirm this behavior in 1.18.1.
Here's a code analysis of this issue. The following is based on a decompiled version of Minecraft 1.18.1 using MCP-Reborn.
Code Analysis:
net.minecraft.world.entity.monster.Witch.java
public class Witch extends Raider implements RangedAttackMob {
...
private static final AttributeModifier SPEED_MODIFIER_DRINKING = new AttributeModifier(SPEED_MODIFIER_DRINKING_UUID, "Drinking speed penalty", -0.25D, AttributeModifier.Operation.ADDITION);
...If we look at the above class, we can see that when witches drink potions, their movement speed modifier is -0.25D.
Is this an issue on 1.12.2?