[MC-8471] Blocks cannot be placed on a block you are next to

The bug

Sometimes blocks cannot be placed on a block you directly standing next to. When you place them they appear for a short moment (client-side) but directly afterwards disappear.

How to reproduce

Dig a 1 block deep hole
Move up against any side or corner of the hole
Attempt to place a repeater or comparator on the block you moved towards
→ The repeater will appear and disappear immediately, as if the server thinks you are occupying the space and cannot place a block.

If you cannot reproduce the bug, try sprinting against the block.

Cause

The cause seems to be that the server thinks the player is intersecting with the collision box of the block to be placed while the client thinks he is not.

For example

To check: box[13.0, 4.0, 8.0 -> 14.0, 4.875, 9.0]

Client player: box[14.0, 4.0, 8.080747030085668 -> 14.600000023841854, 5.799999952316284, 8.680747053927526]
Server player: box[13.999999999999998, 4.0, 8.085848427457286 -> 14.600000023841856, 5.799999952316284, 8.685848451299144]

However, it is interesting that the server let the client move inside the block in the first place.

Code analysis

Based on 1.11.2 decompiled using MCP 9.35 rc1

~~Removed part~~
The reason why the method net.minecraft.network.NetHandlerPlayServer.processPlayer(CPacketPlayer) did not prevent the movement then is because it contracts the player bounding box by 0.0625. Removing this might solve the problem as well, but could result in the player being teleported back when running with the speed effect against a wall or similar.

Edit: Code analysis was partwise wrong. The actual reason is not quite clear.

Linked issues

is duplicated by 10

MC-12029 Jumping and placing Redstone repeater will cause repeater to disapear and be lost forever. Resolved

MC-18208 placing repeaters in creative Resolved

MC-48517 Can't place blocks in certain places Resolved

MC-49097 carpets Resolved

MC-52888 Standing in certain locations prevents nearby block placement Resolved

5 more links

relates to 1

MC-2208 Blocks with special placement can be placed inside player / entity Resolved

Comments 46

Tails 2013-01-26T23:17:08Z

Unable to reproduce. Please provide screenshots.

Kevin Reid 2013-01-26T23:26:09Z

Now I can't reproduce it either, having restarted. Sorry for the noise!

DicoTheRedstoner 2013-01-27T00:49:04Z

I've also experienced this issue, actually
( a lot )

Jesper the End 2013-02-15T19:52:16Z

it's uploading: http://youtu.be/eJWHE-nIivQ

Kevin Reid 2013-02-16T01:50:27Z

I agree that the behavior in the above video is similar to what I experienced when I made this report.

36 more comments

Jesper the End 2013-03-08T22:29:06Z

Can you please reopen this ticket? The prove is in the video.

Tails 2013-03-08T23:30:00Z

Reopened.

Jesper the End 2013-03-09T09:46:38Z

thanks ;P

Anon Ymus 2013-03-09T12:56:49Z

I cannot reproduce in 1.5. Resolving as fixed.

kumasasa 2014-02-23T22:44:39Z

Reopened due to MC-48517

Jesper the End 2014-02-23T23:59:34Z

why is this reopened all of a sudden?

kumasasa 2014-02-24T05:57:21Z

Jesper the End :

[Mod] Kumasasa added a comment - Yesterday 11:44 PM
Reopened due to MC-48517

Itouch2 2014-02-28T14:32:27Z

Confirmed for 1.7.4, 1.7.5 and 1.8 snapshots

Arjan de Vries 2014-07-17T22:23:31Z

More like repeaters, comparators and all other blocks. I think this bug is too major to be hidden away like this. Reproduceable in all snapshots. If you're lucky.

Jesper the End 2014-07-17T22:56:42Z

not being able to place certain blocks is not too much of a problem for me, but this also affects selectors. when you do /execute @a[x,y,z,0] inside a block, it will still detect the player, even though the coordinates are inside a block. And that kinda bugs me

Arjan de Vries 2014-07-23T10:34:46Z

It's not really a problem, but it looks really crappy, as it happens quite frequently when you are an intensive MC builder. Could a mod please update the title based on some closed duplicates? And also update the version to snapshot 29b?

Arjan de Vries 2014-07-23T10:37:55Z

https://www.youtube.com/watch?v=TKVL1R5C-Nw

Here, I uploaded this to prove it affects all blocks

Jesper the End 2014-07-23T12:37:11Z

Well for me it doesn't just look crappy, it's also a problem for me since my redstone breaks because of this bug

Darin Triplett 2014-08-08T03:25:24Z

Confirmed in...well I've seen this since as long as I can remember playing (1.4.x?) Repeaters (and Comparators since they were introduced) have always been glitchy to place. This happens for me with Repeaters and Comparators when laying out complex redstone and appears to be different than MC-58153, which I notice when building in general. The more I think about it, This seems to have been around for awhile and I've only recently tried to reproduce and report it since my 1.8 snapshot LP. With the new launcher, I will have to go back and attempt to reproduce MC-8471 and MC-58153 in previous version.

Jesper the End 2014-08-09T06:47:46Z

confirmed for 14w32d

galaxy_2alex 2014-10-25T10:04:20Z

Cannot Confirm in 1.8.1 Pre3 on Singleplayer. Was not able to test Multiplayer.

Arjan de Vries 2014-10-27T00:02:11Z

This issue still exists in 1.8.1 pre-3 and still affects ALL BLOCKS.

Why the title is still only alluding to repeaters and comparators is beyond me. I posted a video on july 23rd in this thread. Here it is again:

https://www.youtube.com/watch?v=TKVL1R5C-Nw

Arjan de Vries 2014-10-27T00:15:04Z

https://www.youtube.com/watch?v=77dkxtap-l0&list=UUek3flso2pgg_QoptI57pJw

Heres proof that it still happens in 1.8.1 pre-3...

Jeremy 2014-11-01T11:00:06Z

Cannot reproduce in 1.8.1 pre-3. The video shown by Arjan might have been an upside down side stair oriented perpendicular to the player. That (and the accompanying 1/4 block quarter stair hitbox issue) can create a situation like the one shown in the video.

Arjan de Vries 2014-11-01T19:49:19Z

It's not always reproducable. If it isn't, try playing walking a few minutes and try again. It has nothing to do with orientation of stairs. It happens with blocks, and lately I also experienced it when placing ladders while climbing. I can reproduce, whenever I want, although sometimes I need to play for a few minutes.

Marno 2014-11-04T06:38:40Z

Here is an image sequence (note the timestamps of the screenshots) to try and show this happening with oak wood. Also had it happen to a comparator earlier.

Was standing on a ladder when trying to place the block, it would disappear and when I right-click again it appears back in the hot-bar.

Someone 3x7 2015-02-20T00:56:36Z

I originally posted this to MC-58153 before finding this much older issue. This is very easy to recreate. When placing a block at foot level in front of you while crouched it occurs at exactly 7/10ths of the block your in(in the direction your facing). Although does require some movement. Facing east while standing on 0.7 64 0.5 hold shift and tap forward and back keeping near X 0.7 while trying to place block at 1 65 0. Of coarse its easier in creative where can instantly destroy the block when it does get placed. These steps work anywhere, I just felt east in a positive chunk was easier to explain. East in a negative chunk would be at -0.3 instead, etc

Edit: release version 1.8.2

a 2015-06-24T20:52:26Z

I can't reproduce this consistently, though I have had it occur in 1.8.7 on LAN. I was laying half slabs on the bottom half of the block, in the air, and I was sneaking over the edge to lay them in a row, and the block would flash for an instant and then disappear again if I was holding the arrow keys off the edge, OR if I was still moving a tiny bit. If I slowed down to a sure stop each and every time, the block would never flash and it would place properly.

Moon Heroin 2015-08-05T16:31:28Z

This still happens in 15w32a. But only at certain places in a map and/or in certain directions. Happens in both creative and survival. This can ruin the ladder in main hand, a block in other hand climbing trick. Please fix.

ziggurism 2016-02-02T15:34:41Z

Came here from MC-44773. Can confirm this bug in 16w04a.

ziggurism 2016-02-03T17:55:35Z

Confirmed for 16w05a.

ziggurism 2016-02-04T18:26:01Z

Confirmed for 16w05b.

ziggurism 2016-02-17T18:16:50Z

Confirm for 1.9-pre1

ziggurism 2016-02-19T00:40:27Z

Confirm for 1.9-pre2

ziggurism 2016-02-24T19:27:43Z

Confirm for 1.9-pre3