[MC-108313] Ocelots and wolves jump off cliffs while chasing other mobs

The bug

When ocelots chase chickens or when wolves chase skeletons or sheep they jump towards their target without testing if they can land where they are jumping to.

Reproduction steps

Build the setup as shown in the attachment below:

[media]

(2 blocks with 3 blocks of air in between)
Summon a chicken or sheep on the diamond block, and an ocelot or a wolf on the emerald block.
❌ Sometimes the ocelot or wolf jumps into the gap between the blocks

The reason

The following is based on a decompiled version of Minecraft 1.10 using MCP 9.30.

This happens probably because the method net.minecraft.entity.ai.EntityAILeapAtTarget.shouldExecute() does not test if at the position where the mob is supposed to leap to is a block.

Linked issues

relates to 2

MC-178930 Piglins and Piglin Brutes can sometimes fall off an edge Open

MC-77732 Rabbits willingly take fall damage from 3 high blocks Reopened

Attachments

MC-108313.mp4

Comments 21

Ignacio Carvallo 2016-10-06T01:01:53Z

I think that works ok, is not a bug

marcono1234 2016-10-06T11:52:16Z

Edit: Commented on wrong ticked, thanks @unknown

SunCat 2016-10-06T13:25:14Z

@unknown, you commented on the wrong ticket.

marcono1234 2016-10-06T13:34:41Z

Thank you, that was the analysis for MC-99603

carpet0928 2018-09-26T23:13:26Z

Still present in 1.13.1.

11 more comments

carpet0928 2018-10-19T10:04:55Z

Confirmed for 1.13.2-pre2.

Lightning_11 2019-09-09T12:57:05Z

I think that this might be more a feature than a bug. Those mobs might be getting really angry and not blindly chasing prey without regard for their own safety. However, I think there should be a few blocks that would slow them down. For example, they shouldn't jump into lava or portals, no matter how angry they might be. Those things are so obvious that you shouldn't be able to jump into them just because you weren't looking where you where going.