[1.21.4] Regression in the effects of modded fluids on entity movement.

[bconlon1]

Minecraft Version: 1.21.4

NeoForge Version: 21.4.50-beta

Logs: N/A; Code:

• https://github.com/The-Aether-Team/The-Aether-II/blob/1.21.4-develop/src/main/java/com/aetherteam/aetherii/block/AetherIIFluidTypes.java
• https://github.com/The-Aether-Team/The-Aether-II/blob/1.21.4-develop/src/main/java/com/aetherteam/aetherii/block/fluid/AcidFluid.java

Steps to Reproduce:

1. Create and register a custom fluid that does not incorporate any custom movement effects.
2. Jump into the fluid.
3. Notice the player will sink to the bottom immediately and their movement will behave as if they aren't in any fluid; except they are prevented from jumping notably.

java_K9RkEHHrMs.mp4

Description of issue:
It seems like there's been a regression in custom fluid behavior between 1.21.1 and 1.21.4. I believe the difference is in that this patch code from 1.21.1 moved to the LivingEntity#travelInFluid method in 1.21.4, but a patch has not been added here to LivingEntity#travel before the new travelInFluid method is called:

[luxtracon]

Can confirm the same behaviour for Neo 21.3.58

[sciwhiz12]

Confirmed on 21.4.76-beta, using the test fluid (new_fluid_test:test_fluid) which exhibits no custom movement property. Falling into the fluid and walking in it acts as if the fluid isn't there, but jumping is prevented.

[sciwhiz12]

Oh. The test fluid does have movement behavior, but because of the missing patch that prevents travelInFluid from being called when in a custom fluid type, the game never does the fluid movement.

Re-adding the patch to LivingEntity#travel as suggested in the issue description--inserting this.isInFluidType(fluidstate) to the OR conditional for water and lava--fixes the issue, and restores the proper fluid movement.

[neoforged-releases]

🚀 This issue has been resolved in NeoForge version 21.4.77-beta, as part of #1922.