[MC-156022] Mobs' pathfinding breaks when on waterlogged top slabs

The bug

Entities have difficultly pathfinding when standing on waterlogged top slabs.

Similarly to MC-136318, the mobs will stop moving and spin when on top of a waterlogged block. In 1.14.4 Pre-Release 2, the pathfinding was fixed for most waterlogged blocks. However, the pathfinding is still bugged if the block is the top half of a waterlogged slab.

How to reproduce

Run the following command:

/fill ~10 ~-1 ~10 ~-10 ~-1 ~-10 minecraft:cut_copper_slab[waterlogged=true,type=top]

Summon a cow on top of the cut copper slabs
Attack the cow

Observed behavior

The cow does not panic; it has difficulty pathfinding while on waterlogged top slabs.

Expected behavior

The cow would panic; Entities would not have difficultly pathfinding while on waterlogged top slabs.

Linked issues

is duplicated by 8

MC-158278 Skeletons and Creepers' behavior on waterlogged top slabs Resolved

MC-158419 Mob AI Bugs out on Waterlogged Upside-down Half-Slabs Resolved

MC-158837 Chickens spin in circles when on slabs Resolved

MC-160266 wandering trader spinns on slab blocks Resolved

MC-161091 Villager spinning in solo too Resolved

3 more links

relates to 1

MC-157645 Mobs cannot pathfind properly on bottom slabs, farmland, dirt paths, and other blocks without a solid top face Open

Attachments

MC-156022.mp4

Comments 22

Jon1337 2019-08-27T12:16:01Z

Confirmed for 19w34a

Jon1337 2019-09-19T20:30:56Z

Affects 19w38b

Frostbite 2019-10-18T22:21:09Z

Affects 19w42a

Jon1337 2020-03-21T13:06:01Z

Affects 20w12a

Pelle Reinke 2020-03-26T12:22:20Z

Affects 20w13a.

12 more comments

Jon1337 2020-03-27T14:06:29Z

Affects 20w13b

Pelle Reinke 2020-04-20T19:05:04Z

still present in 20w16a

Pelle Reinke 2020-04-20T19:14:52Z

If there's carpet on top of the waterlogged halfslap, it completely stops the mobs pathfinding and they will stand completely still.

Pelle Reinke 2020-05-13T18:36:44Z

I'm not able to reproduce this any longer in snapshot 20w20a.

[Mod] LateLag 2020-10-01T17:35:14Z

Can someone else confirm that it's no longer occurring?

Sam Carlberg 2020-12-07T02:07:59Z

I still see this on 1.16.4. It also seems to prevent villagers from breeding or using a work block

Hostile mob pathfinding: https://www.youtube.com/watch?v=UweKHv-XSn8

Avoma 2020-12-20T17:55:12Z

Sam Carlberg

In that video, you were using Optifine, therefore making your statement invalid. I can confirm that this issue no longer occurs in 20w51a. Mobs have no trouble pathfinding over waterlogged upper slabs.

[Mod] LateLag 2021-02-16T10:47:21Z

Can confirm that some part of it still occurs. They can move just fine, but they might start spinning randomly.

Avoma 2021-06-18T13:13:07Z

Can confirm in 1.17.

Avoma 2021-07-20T09:11:11Z

Can confirm in 1.17.1.

Avoma 2021-11-20T14:58:14Z

Here are some steps on how to go about reproducing this. I've also attached a video demonstrating this issue.

[media]

The Bug:

Entities have difficultly pathfinding when standing on waterlogged top slabs.

Steps to Reproduce:

Summon some waterlogged top slabs beneath you.

/fill ~10 ~-1 ~10 ~-10 ~-1 ~-10 minecraft:cut_copper_slab[waterlogged=true,type=top]

Summon a cow on top of the slabs.
Attack the cow and watch its behavior closely.
Take note as to whether or not the cow panics upon being attacked.

Observed Behavior:

Entities have difficultly pathfinding when standing on waterlogged top slabs.

Expected Behavior:

Entities would not have difficultly pathfinding when standing on waterlogged top slabs.

Avoma 2021-12-20T16:39:04Z

Can confirm in 1.18.1.

Avoma 2022-03-31T16:01:30Z

Can confirm in 1.18.2.

TiredRedstoner 2023-02-04T02:19:37Z

I can confirm in 23w05a

Jon1337 2023-08-09T18:51:15Z

In 23w32a

There's also an issue with hostile mob pathfinding to a player who is standing on waterlogged top slabs, where they take an unnecessarily long path to them instead of a direct one

himazinn_Japan 2024-11-12T12:32:56Z

Can confirm in 24w45a.

Minecraft386882 2024-11-19T12:38:08Z

Confirmed in 1.21.3