[MC-98727] Server: Entering a boat/minecart/horse while going upwards from jumping causes a kick for flying

The bug

So on a multiplayer server, if you jump off the ground and then right click on a ridable entity like for example a horse before landing you will get kicked from the server for flying too long and in the server log you will see a message such as:

[17:54:58] [Server thread/WARN]: Jobe was kicked for floating too long!

Code analysis

Based on 1.11.2 decompiled using MCP 9.35 rc1

The server does not reset the field net.minecraft.network.NetHandlerPlayServer.floating when a player starts riding an entity even though it is tracking floating with the field net.minecraft.network.NetHandlerPlayServer.vehicleFloating there and because the floating field can only be set to false by the part of the method net.minecraft.network.NetHandlerPlayServer.processPlayer(CPacketPlayer) which runs if the player is not riding an entity the value remains true.

Attachments

crash-2016-03-02_21.15.33-client.txt

Comments 27

Yottazoid 2016-07-24T00:59:22Z

Can confirm in 1.10.2

Jeuv 2016-12-20T21:49:04Z

Haven't been able to reproduce for a few weeks; possibly fixed in 1.11.

Uriel Salischiker 2016-12-20T21:49:48Z

Can you check in 1.11.1?

Jeuv 2016-12-20T21:58:49Z

Same deal, this might have been spigot related all along.

Edit: not true

Yottazoid 2016-12-20T22:39:32Z

I was able to reproduce on a vanilla 1.11.1 server if I was to mount after falling back down after jumping.
It only does it in survival mode and didn't matter if I was OP or not.

17 more comments

Uriel Salischiker 2016-12-20T22:42:23Z

Also the crash log you provided is for a manually triggered crash

Jeuv 2016-12-21T16:54:07Z

The crash log is to prove it was a vanilla client & server.

marcono1234 2017-05-08T09:10:47Z

Set the gamemode to "None" because it should affect Survival and Adventure mode

Kevin He 2017-08-13T20:56:31Z

I can't reproduce it using boat in 1.12.1. But it can still be reproduced by riding minecarts/horses/llamas.

If you can't reproduce it, make sure the server has allow-flight=false in its server.properties file so it will kick out players in survival/adventure mode for floating longer than 5 secs.

ipyronic 2017-08-14T00:12:18Z

I can reproduce this practically every time I try. Simply jump, wait a fraction of a second, and then ride the entity before you start falling down again. Latest versions tested: Vanilla 1.12.1, Spigot 1.12.1

Must be on a multiplayer server (not singleplayer) with allow-flight off and you must be in survival/adventure mode (not creative). It doesn't matter if you are OP or not.

Happens when riding any entity (even ones which normally can't be ridden such as armor stands). I first discovered this bug while riding armor stands using a chair plugin on a spigot server.

In response to Kaiwen He's comment: It still happens to me for boats in vanilla 1.12.1.
In response to Yottazoid's comment: I cannot get it to happen while I am falling down, only when going up D:

Matthew Beeching 2017-10-26T16:47:01Z

I have also been able to reproduce this using a bed in 1.12.2. It is definitely still present. So simply needs you to perform an action whilst jumping that doesn't count as landing from the jump leading the server to believe you are still in the air.

genandnic 2017-12-24T23:23:54Z

Confirmed for 1.12.2. This bug is especially problematic, seeing this can cause false accusations of cheating.

Asteraoth 2018-09-04T00:52:00Z

Can confirm.

user-2a4c8 2019-03-23T17:47:43Z

19w12b

user-2a4c8 2019-03-29T18:31:08Z

This happens with beds too. Same bug? 19w13b.

ZeNico13 2019-05-13T17:07:51Z

Still in 1.14.1 Release

Matthew Beeching 2019-05-13T19:10:20Z

Can confirm in 1.14.1. Was riding a horse, got off for a moment, jumped as I was getting on, kicked from server.

Brendan George 2019-05-14T01:52:27Z

Can Also confirm in 1.14.1

ZeNico13 2019-05-17T19:17:37Z

Still in 1.14.2 Pre-Release 1 and 1.14.2 Pre-Release 2

Loek van Vucht 2020-06-19T09:55:51Z

Does this bug apply to striders as well? If so, MC-190266 is more common.

Jax6563 2020-09-05T01:52:02Z

still in 1.16.2

Avoma 2021-04-13T18:36:57Z

Can confirm in 21w14a.

user-d1c12 2021-06-12T08:21:44Z

Flying hack doesn't kick players.

Yottazoid 2021-06-12T08:52:23Z

Can confirm in 1.17 release.

Marty McFly 2021-10-12T19:22:18Z

Affects 21w40a

Matthew Beeching 2021-12-04T23:11:17Z

Confirmed in 1.18, despite this bug being confirmed as early as 1.9 (likely earlier too), really disappointing that after all these years it still hasn't been fixed.

Avoma 2021-12-31T17:31:28Z

Can confirm in 1.18.1.