The bug
When certain block entities such as a dropper/dispenser or a command block that contain NBT data for items or a command is either placed manually on a power source or cloned on a power source it will receive power because a repeater gets power from the side of it but the dispenser will not place/drop anything and the command block will not run the command.
How to reproduce
Place down a dispenser or dropper or command block
Put items or a command into the block, depending what it is
Control and middle-click the block to get the block with NBT data
Place this on a power source such as a redstone torch or a redstone block
→ It should run the command or drop/place something but it does not
Note: this also affects note blocks, they won't play a note until they received a block update.
Test command for falling block, insert into a command block and trigger:
summon falling_block ~ ~2 ~ {
BlockState:{Name:"minecraft:stone"},
Time:1s,
Passengers:
[
{
id:"falling_block",
BlockState:{Name:"minecraft:redstone_block"},
Time:1s,
Passengers:
[
{
id:"falling_block",
BlockState:{Name:"minecraft:command_block"},
TileEntityData:{Command:"say Test"},
Time:1s
}
]
}
]
}Related issue
MC-31100 when using /setblock to place the block it does not update (and more)
Code analysis
Code analysis by @unknown can be found in this comment on bug report MC-18631.
Related issues
is duplicated by
MC-18631
Some redstone components (block entities) do not update themselves when placed
MC-73882
Dispenser does not look for redstone power when placed
MC-75576
Redstone Repeater Bug
MC-80901
Landed Falling Block does not trigger redstone updates for block entities (Command Blocks, ...)
MC-86663
Chain Command Block not powered by Redstone Block when Chain Block is placed next to or on a Redstone Block before being turned from Impulse to Chain.
MC-87131
Repeated Command Block Activation Issues
MC-88681
when summoning falling sand riding falling sand upper most command block does not activate
MC-91510
All command blocks DO NOT respond to redstone blocks when placed w/ custom tag
MC-105522
Detecting wool in a commandblock
MC-156919
Block doesn't get triggerd by redstone after you placed it
MC-233642
Items with BlockStateTag placed will not update redstone.
MC-266379
Some blocks stay unpowered when placing adjancent redstone blocks
Comments
galaxy_2alex
Reopened, thanks.
This behavior is somewhat useful as you can use command blocks as block update detectors
Confirmed for 1.12 pre-7.
Please consider what I wrote here.
I'm more than willing to take over all 4 bugposts or, preferrably, all of them bundled into the oldest one, if the OP regarding that type of problem (MC-18631) doesn't update it; I would also list all 4 test setups for bug reproduction into that one.
Meri if you would like to take over this bug post you are more than welcome to.
I am not sure what the process to go about transferring it is though
Hello there!
If you're fine with it, usually the moderators wouldn't oppose transferring and might do so as soon as they see it, unless there'll be a merge of all bugposts including this one, which anyone else might get assigned to, no idea, up to them.
Whenever someone (like we did now) does any changes to a bugpost, including comments, it seems to get into their update feed, so they will see our comments here eventually and then make a decision 🙂
Thank you, have a good day and take care!
wobst.michael
Gave ticket to @unknown
Panda4994
Confirmed for 1.13pre4.
Panda4994
Confirmed for 1.13-pre6.
Panda4994
Confirmed for 1.13-pre7.
Panda4994
Confirmed for 1.13-pre8.
Panda4994
Confirmed for 1.13.
Confirmed for 1.13.1.
CreeperMagnet_
Confirmed for 1.16.4 and most recent snapshot (20w48a).
confirmed for 20w49a
Still an issue in snapshot 20W51A
Still an issue in snapshot 21w03a
Hayden Wong
Still an issue in 1.17.1.
Also affects items with BlockStateTag when placed, even when that block is not a block entity, see this video.
ampolive
Since this also affects blocks which are not block entities, such as composters and note blocks, I have updated the title to reflect this.
This is still a problem but I feel like it is probably going to be marked as "Works as Intended"