[MC-72248] Falling sand creates invisible blocks

The Bug:

Falling sand creates invisible blocks.

Steps to Reproduce:

Run the following command whilst standing on a stone block.

/summon minecraft:falling_block ~ ~-1 ~ {Time:1,Motion:[0.0,1.0,0.0],BlockState:{Name:"minecraft:stone"}}

Take note as to whether or not falling sand creates invisible blocks.

Observed Behavior:

Falling sand creates invisible blocks.

Expected Behavior:

Falling sand would not be able to create invisible blocks.

Code Analysis:

Code analysis by @unknown can be found in this comment.

Linked issues

is duplicated by 17

MC-55106 FallingSand creates an invisible glitch block Resolved

MC-74271 FallingSand with Spawner (when it spawn on the ground) don't work at 1.8+ Resolved

MC-75096 Command Blocks dissapear when fallingsand entitys are summoned at the same cordinates Resolved

MC-101553 FallingSand entity creates ghost blocks Resolved

MC-110627 Falling Sand Causes Glitchy Barriers Resolved

12 more links

relates to 2

MC-56037 Killing falling_block entity: texture disappears while falling but the block is still there Resolved

MC-114286 Falling block does not render if same block state is at the block position Open

Attachments

Comments 33

migrated 2014-09-22T14:08:25Z

Confirmed in single player survival. Very interesting. However this appears to be a duplicate of MC-48476.

migrated 2014-09-22T15:19:39Z

confirmed just if anyone misunderstands it, the block your standing on becomes invisible

migrated 2014-09-22T15:40:48Z

Someone might double check me since I'm a newb. The dupe I mentioned above looks right for what he's reporting but it might be something slightly different. Apologies if I got it wrong.

migrated 2014-09-22T16:26:44Z

it is diffrent, this is about the block below turning invisible, that was about the summoned falling sand turning invisible

migrated 2014-09-22T19:55:58Z

"it is diffrent, this is about the block below turning invisible, that was about the summoned falling sand turning invisible"
True, I use this for a plugin that is how I found out.

23 more comments

mrpingouin1 2014-09-26T10:30:32Z

The Tag TileID is deprecated, use the tag Block instead

migrated 2014-09-26T14:25:34Z

it may be depreciated, but this bug also happens when using the Block tag

marcono1234 2015-01-22T14:16:49Z

Confirmed for

1.8.2-pre4 The FallingSand doesn't need a velocity upwards

What is also strange, when you use

/summon FallingSand ~ ~-1 ~ {Time:1,Block:command_block,TileEntityData:{Command:/say Hi}}

And do this on top of a command block with a command in it, then place at the bugging block another block (like stone), all NBT data gets deleted.

This only happens when you try to "overwrite" the bugged block. When you reopen the world, the first command block has still its command.

migrated 2015-02-03T00:09:21Z

This is dupe of MC-55106.

migrated 2015-02-17T06:00:17Z

I believe I know the cause of this bug. FallingSand entities have a special behavior where they delete the block they are inside if it has the same ID and their Time = 0. You can see the 1.7 implementation of this behavior here:

https://github.com/Bukkit/mc-dev/blob/master/net/minecraft/server/EntityFallingBlock.java#L76

The isStatic check above makes this code only run on the server. In the 1.8 code (which is not online for me to link to) this was moved outside the isStatic check and so the client is running it too. Because the Time property is not sent to the client, FallingSand entities always spawn with Time 0 and thus always delete the block.

marcono1234 2015-09-11T15:20:18Z

Confirmed for

15w37a

Duplicates indeed MC-55106, but as this one is more active I rather suggest marking the other report as duplicate

migrated 2015-11-22T19:38:16Z

Confirmed for 15w47c

https://youtu.be/J3EiojcvJvY

migrated 2016-02-26T03:33:05Z

Still seeing it as of 1.9 pre 2, I get it using a fast shovel, beating up a mix of dirt and sand or gravel on a low-ping or local vanilla server, survival, no commands are needed.

migrated 2016-02-26T19:28:54Z

@@unknown: MC-5694.

migrated 2016-02-26T22:42:40Z

Yes, my problem was MC-5694. 🙂

I then took the time to verify our issue here, MC-72248, for 1.9pre4, as 'thanks'. 😛

kumasasa 2016-02-27T10:58:51Z

@unknown: Is 1.9-pre4 affected or not ?

migrated 2016-02-27T15:47:25Z

Ugh, been too long out of a shop... 'verify' is usually for fixes. :/

Sadly, 1.9-pre4 is still affected by summoned falling sand creating invisible blocks.

migrated 2016-03-13T16:54:58Z

The enviroment is supposed to contain pc details.

marcono1234 2016-05-30T11:42:45Z

Confirmed for

16w21b

Please update the provided command. The Block tag (String) is used now

marcono1234 2016-05-30T11:51:45Z

Please link to this comment in the description

The following is based on a decompiled version of Minecraft 1.9 using MCP 9.24 beta.

It looks like @unknown was correct with his analysis (method net.minecraft.entity.item.EntityFallingBlock.onUpdate()). Replacing an existing block should be done server-side only because the client receives the block update packets anyways.

JUE13 2017-05-31T04:22:15Z

Confirmed for 1.12-pre6