MC-114104Some actions apply the same NBT object instance to multiple items entities or tile entities instead of applying a copy
The bug
Some actions in the game apply the same NBT object instance to multiple items, entities or tile entities. This means if you edit it for one of them you basically edit it for all of them.
This could in theory happen with non-NBT data as well, but at least in the current versions this is not the case because either:
- the data is stored in primitive types and therefor no objects are involved
- the data is provided in NBT format but then parsed and stored with objects; therefor no reference to the NBT data exists anymore
Some of the cases listed below might happen when the NBT data is read or written by entities or tile entities. The expected fix is however not to have them always create a copy because that would slow down saving and loading worlds. Instead the methods calling these methods should create a copy before respectively after.
The reason why this report contains a list of all cases, even the ones which are not affected, is to have an overview and make it easier to detect new cases in which this happens.
Actions
Affected key
| Symbol | Meaning |
|---|---|
 |
Affected |
 |
Not affected |
 |
Currently not affected, but current behavior is listed as bug and therefor likely affected in the future |
List
Based on 1.11.2 decompiled using MCP 9.35 rc1
Last updated for 1.11.2
Likely incomplete
| Action | Affected | Comment | Affected method |
|---|---|---|---|
| Pick block with NBT | |
Currently happens client-side, but should happen server-side | Minecraft.storeTEInStack(ItemStack, TileEntity) |
| Copying items in Creative | |
- | - |
| Crafting: Cloning books | |
- | - |
| Crafting: Cloning banners | |
- | - |
| Crafting: Cloning maps | |
- | RecipesMapCloning.getCraftingResult(InventoryCrafting) |
| Creating item in Creative with BlockEntityTag | |
- | NetHandlerPlayServer.processCreativeInventoryAction(CPacketCreativeInventoryAction) |
| Using item with EntityTag | |
Dispenser, spawn eggs, armor stand... | ItemMonsterPlacer.applyItemEntityDataToEntity(World, EntityPlayer, ItemStack, Entity) |
| Item with BlockEntityTag placed | |
- | - |
| Items from loottables | |
Uses NBTTagCompound.merge which clones | - |
| Items from villagers | |
- | - |
| Splitting item stacks | |
- | - |
| Hopper (minecart) item actions | |
- | - |
| Droppers transferring items | |
- | - |
| Cleaning banner in cauldron | |
- | - |
| Cleaning leather armor in cauldron | |
Even in Creative stack is replaced and water level reduced, not the case with banners, see MC-114105 | BlockCauldron.onBlockActivated(World, BlockPos, IBlockState, EntityPlayer, EnumHand, EnumFacing, float, float, float) |
| Putting item on armor stand | |
- | - |
| Using firework | |
- | - |
| Putting item in item frame | |
Only cloned when not empty, but even if empty set as item | EntityItemFrame.setDisplayedItemWithUpdate(ItemStack, boolean) |
| Putting chest on donkey or mule | |
Entity does not store item data but only boolean, see |
- |
| Putting saddle on pig | |
Entity does not store item data but only boolean, see |
- |
| Dispenser / dropper dropping item | |
- | - |
| Dispenser placing player skull | |
GameProfile is read and stored | - |
| Dispenser shooting tipped arrow | |
Potion effects are read and stored | - |
| Dispenser throwing splash or lingering potion | |
- | - |
| Dispenser equipping armor (including pumpkin, elytra and skull) | |
- | - |
| Dispenser playing shulker box | |
- | - |
| /clone | |
See paragraph "How to reproduce" for reproduction | CommandClone.execute(MinecraftServer, ICommandSender, String[]) |
| /fill | |
Fixed, see |
CommandFill.execute(MinecraftServer, ICommandSender, String[]) |
| /entitydata | |
Runs for each entity seperately and uses NBTTagCompound.merge which clones | - |
| /replaceitem entity | |
Runs for each entity seperately | - |
| Structure blocks loading and saving | |
See |
- |
How to reproduce
Some of these cases cannot be reproduced because other actions only override the affected data instead of modifying it, or other actions create a copy before you could try to reproduce them. Therefor here are only reproduction steps for some actions.
/clone
- Place a spawner
/setblock ~ ~ ~ spawner{SpawnData:{id:"armor_stand"},SpawnCount:0s,SpawnRange:0s,MinSpawnDelay:0s,MaxSpawnDelay:0s,MaxNearbyEntities:1s,RequiredPlayerRange:16s,SpawnPotentials:[{Weight:1,Entity:{id:"bat"}}]} - Stand on top of the spawner and run the following command
/clone ~ ~-1 ~ ~ ~-1 ~ ~2 ~-1 ~
- For the cloned spawner
- Make it switch to the SpawnPotentials (stand on top of it while running the command)
/data modify block ~ ~-1 ~ SpawnCount set value 1b
- Right click the spawner with a creeper spawn egg
- Make it switch to the SpawnPotentials (stand on top of it while running the command)
- For the original spawner
- Inspect the NBT data
/data get block ~ ~-1 ~ SpawnPotentials
It shows "minecraft:creeper" as entry for the SpawnPotentials instead of "minecraft:bat"
- Inspect the NBT data
/fill
Fixed by MC-163953 
Linked Issues
Created Issue:
Some actions apply the same NBT data to multiple items entities or tile entities instead of applying a copy
The bug
Some actions in the game apply the same NBT object instance to multiple items, entities or tile entities. This means if you edit it for one of them you basically edit it for all of them.
This could in theory happen with non-NBT data as well, but at least in the current versions this is not the case because either:
- the data is stored in primitive types and therefor no objects are involved
- the data is provided in NBT format but then parsed and stored with objects; therefor no reference to the NBT data exists anymore
Some of the cases listed below might happen when the NBT data is read or written by entities or tile entities. The expected fix is however not to have them always create a copy because that would slow down saving and loading worlds. Instead the methods calling these methods should create a copy before respectively after.
The reason why this report contains a list of all cases, even the ones which are not affected, is to have an overview and make it easier to detect new cases in which this happens.
Actions
Affected key
Symbol Meaning Affected Not affected Currently not affected, but current behavior is listed as bug and therefor likely affected in the future List
Based on 1.11.2 decompiled using MCP 9.35 rc1
Last updated for 1.11.2
Likely incomplete
Action Affected Comment Affected method Pick block with NBT Currently happens client-side, but should happen server-side Copying items in Creative - - Crafting: Cloning books - - Crafting: Cloning banners - - Crafting: Cloning maps - Creating item in Creative with BlockEntityTag - Using item with EntityTag Dispenser, spawn eggs, armor stand... Item with BlockEntityTag placed - - Items from loottables Uses NBTTagCompound.merge which clones - Items from villagers - - Splitting item stacks - - Hopper (minecart) item actions - - Droppers transferring items - - Cleaning banner in cauldron - - Cleaning leather armor in cauldron Even in Creative stack is replaced and water level reduced, not the case with banners Putting item on armor stand - - Using firework - - Putting item in item frame Only cloned when not empty, but even if empty set as item Putting chest on donkey or mule Entity does not store item data but only boolean, see MC-91005- Putting saddle on pig Entity does not store item data but only boolean, see MC-91005- Dispenser / dropper dropping item - - Dispenser placing player skull GameProfile is read and stored - Dispenser shooting tipped arrow Potion effects are read and stored - Dispenser throwing splash or lingering potion - - Dispenser equipping armor (including pumpkin, elytra and skull) - - Dispenser playing shulker box - - /clone See paragraph "How to reproduce" for reproduction /fill See paragraph "How to reproduce" for reproduction /entitydata Runs for each entity seperately and uses NBTTagCompound.merge which clones - /replaceitem entity Runs for each entity seperately - Structure blocks loading and saving See See MC-114030- How to reproduce
Some of these cases cannot be reproduced because other actions only override the affected data instead of modifying it, or other actions create a copy before you could try to reproduce them. Therefor here are only reproduction steps for some actions.
/clone
- Place a spawner
/setblock ~ ~ ~ mob_spawner default replace {SpawnData:{id:"armor_stand"},SpawnCount:0s,SpawnRange:0s,MinSpawnDelay:0s,MaxSpawnDelay:0s,MaxNearbyEntities:1s,RequiredPlayerRange:16s,SpawnPotentials:[{Weight:1,Entity:{id:"bat"}}]}- Clone the spawner
/clone ~ ~-1 ~ ~ ~-1 ~ ~2 ~-1 ~- For the cloned spawner
- Make it switch to the SpawnPotentials
/blockdata ~ ~-1 ~ {SpawnCount:1b}- Right click with a creeper spawn egg
- For the original spawner
- Inspect the NBT data
/blockdata ~ ~-1 ~ {}→ It shows "minecraft:creeper" as entry for the SpawnPotentials instead of "minecraft:bat"
/fill
- Fill in spawners
/fill ~1 ~ ~ ~2 ~ ~ mob_spawner default replace {SpawnData:{id:"armor_stand"},SpawnCount:0s,SpawnRange:0s,MinSpawnDelay:0s,MaxSpawnDelay:0s,MaxNearbyEntities:1s,RequiredPlayerRange:16s,SpawnPotentials:[{Weight:1,Entity:{id:"bat"}}]}- For first spawner
- Make it switch to the SpawnPotentials
/blockdata ~ ~-1 ~ {SpawnCount:1b}- Right click with a creeper spawn egg
- For the second spawner
- Inspect the NBT data
/blockdata ~ ~-1 ~ {}→ It shows "minecraft:creeper" as entry for the SpawnPotentials instead of "minecraft:bat"
The bug
Some actions in the game apply the same NBT object instance to multiple items, entities or tile entities. This means if you edit it for one of them you basically edit it for all of them.
This could in theory happen with non-NBT data as well, but at least in the current versions this is not the case because either:
- the data is stored in primitive types and therefor no objects are involved
- the data is provided in NBT format but then parsed and stored with objects; therefor no reference to the NBT data exists anymore
Some of the cases listed below might happen when the NBT data is read or written by entities or tile entities. The expected fix is however not to have them always create a copy because that would slow down saving and loading worlds. Instead the methods calling these methods should create a copy before respectively after.
The reason why this report contains a list of all cases, even the ones which are not affected, is to have an overview and make it easier to detect new cases in which this happens.
Actions
Affected key
Symbol Meaning Affected Not affected Currently not affected, but current behavior is listed as bug and therefor likely affected in the future List
Based on 1.11.2 decompiled using MCP 9.35 rc1
Last updated for 1.11.2
Likely incomplete
Action Affected Comment Affected method Pick block with NBT Currently happens client-side, but should happen server-side Copying items in Creative - - Crafting: Cloning books - - Crafting: Cloning banners - - Crafting: Cloning maps - Creating item in Creative with BlockEntityTag - Using item with EntityTag Dispenser, spawn eggs, armor stand... Item with BlockEntityTag placed - - Items from loottables Uses NBTTagCompound.merge which clones - Items from villagers - - Splitting item stacks - - Hopper (minecart) item actions - - Droppers transferring items - - Cleaning banner in cauldron - - Cleaning leather armor in cauldron Even in Creative stack is replaced and water level reduced, not the case with banners Putting item on armor stand - - Using firework - - Putting item in item frame Only cloned when not empty, but even if empty set as item Putting chest on donkey or mule Entity does not store item data but only boolean, see MC-91005- Putting saddle on pig Entity does not store item data but only boolean, see MC-91005- Dispenser / dropper dropping item - - Dispenser placing player skull GameProfile is read and stored - Dispenser shooting tipped arrow Potion effects are read and stored - Dispenser throwing splash or lingering potion - - Dispenser equipping armor (including pumpkin, elytra and skull) - - Dispenser playing shulker box - - /clone See paragraph "How to reproduce" for reproduction /fill See paragraph "How to reproduce" for reproduction /entitydata Runs for each entity seperately and uses NBTTagCompound.merge which clones - /replaceitem entity Runs for each entity seperately - Structure blocks loading and saving See See MC-114030- How to reproduce
Some of these cases cannot be reproduced because other actions only override the affected data instead of modifying it, or other actions create a copy before you could try to reproduce them. Therefor here are only reproduction steps for some actions.
/clone
- Place a spawner
/setblock ~ ~ ~ mob_spawner default replace {SpawnData:{id:"armor_stand"},SpawnCount:0s,SpawnRange:0s,MinSpawnDelay:0s,MaxSpawnDelay:0s,MaxNearbyEntities:1s,RequiredPlayerRange:16s,SpawnPotentials:[{Weight:1,Entity:{id:"bat"}}]}- Clone the spawner
/clone ~ ~-1 ~ ~ ~-1 ~ ~2 ~-1 ~- For the cloned spawner
- Make it switch to the SpawnPotentials
/blockdata ~ ~-1 ~ {SpawnCount:1b}- Right click with a creeper spawn egg
- For the original spawner
- Inspect the NBT data
/blockdata ~ ~-1 ~ {}→ It shows "minecraft:creeper" as entry for the SpawnPotentials instead of "minecraft:bat"
/fill
- Fill in spawners
/fill ~1 ~ ~ ~2 ~ ~ mob_spawner default replace {SpawnData:{id:"armor_stand"},SpawnCount:0s,SpawnRange:0s,MinSpawnDelay:0s,MaxSpawnDelay:0s,MaxNearbyEntities:1s,RequiredPlayerRange:16s,SpawnPotentials:[{Weight:1,Entity:{id:"bat"}}]}- For first spawner
- Make it switch to the SpawnPotentials
/blockdata ~ ~-1 ~ {SpawnCount:1b}- Right click with a creeper spawn egg
- For the second spawner
- Inspect the NBT data
/blockdata ~ ~-1 ~ {}→ It shows "minecraft:creeper" as entry for the SpawnPotentials instead of "minecraft:bat"
Some actions apply the same NBTdatato multiple items entities or tile entities instead of applying a copySome actions apply the same NBT object instance to multiple items entities or tile entities instead of applying a copy
The bug
Some actions in the game apply the same NBT object instance to multiple items, entities or tile entities. This means if you edit it for one of them you basically edit it for all of them.
This could in theory happen with non-NBT data as well, but at least in the current versions this is not the case because either:
- the data is stored in primitive types and therefor no objects are involved
- the data is provided in NBT format but then parsed and stored with objects; therefor no reference to the NBT data exists anymore
Some of the cases listed below might happen when the NBT data is read or written by entities or tile entities. The expected fix is however not to have them always create a copy because that would slow down saving and loading worlds. Instead the methods calling these methods should create a copy before respectively after.
The reason why this report contains a list of all cases, even the ones which are not affected, is to have an overview and make it easier to detect new cases in which this happens.
Actions
Affected key
Symbol Meaning Affected Not affected Currently not affected, but current behavior is listed as bug and therefor likely affected in the future List
Based on 1.11.2 decompiled using MCP 9.35 rc1
Last updated for 1.11.2
Likely incomplete
Action Affected Comment Affected method Pick block with NBT Currently happens client-side, but should happen server-side Copying items in Creative - - Crafting: Cloning books - - Crafting: Cloning banners - - Crafting: Cloning maps - Creating item in Creative with BlockEntityTag - Using item with EntityTag Dispenser, spawn eggs, armor stand... Item with BlockEntityTag placed - - Items from loottables Uses NBTTagCompound.merge which clones - Items from villagers - - Splitting item stacks - - Hopper (minecart) item actions - - Droppers transferring items - - Cleaning banner in cauldron - - Cleaning leather armor in cauldron Even in Creative stack is replaced and water level reduced, not the case with banners Putting item on armor stand - - Using firework - - Putting item in item frame Only cloned when not empty, but even if empty set as item Putting chest on donkey or mule Entity does not store item data but only boolean, see MC-91005- Putting saddle on pig Entity does not store item data but only boolean, see MC-91005- Dispenser / dropper dropping item - - Dispenser placing player skull GameProfile is read and stored - Dispenser shooting tipped arrow Potion effects are read and stored - Dispenser throwing splash or lingering potion - - Dispenser equipping armor (including pumpkin, elytra and skull) - - Dispenser playing shulker box - - /clone See paragraph "How to reproduce" for reproduction /fill See paragraph "How to reproduce" for reproduction /entitydata Runs for each entity seperately and uses NBTTagCompound.merge which clones - /replaceitem entity Runs for each entity seperately - Structure blocks loading and saving See See MC-114030- How to reproduce
Some of these cases cannot be reproduced because other actions only override the affected data instead of modifying it, or other actions create a copy before you could try to reproduce them. Therefor here are only reproduction steps for some actions.
/clone
- Place a spawner
/setblock ~ ~ ~ mob_spawner default replace {SpawnData:{id:"armor_stand"},SpawnCount:0s,SpawnRange:0s,MinSpawnDelay:0s,MaxSpawnDelay:0s,MaxNearbyEntities:1s,RequiredPlayerRange:16s,SpawnPotentials:[{Weight:1,Entity:{id:"bat"}}]}- Clone the spawner
/clone ~ ~-1 ~ ~ ~-1 ~ ~2 ~-1 ~- For the cloned spawner
- Make it switch to the SpawnPotentials
/blockdata ~ ~-1 ~ {SpawnCount:1b}- Right click with a creeper spawn egg
- For the original spawner
- Inspect the NBT data
/blockdata ~ ~-1 ~ {}→ It shows "minecraft:creeper" as entry for the SpawnPotentials instead of "minecraft:bat"
/fill
- Fill in spawners
/fill ~1 ~ ~ ~2 ~ ~ mob_spawner default replace {SpawnData:{id:"armor_stand"},SpawnCount:0s,SpawnRange:0s,MinSpawnDelay:0s,MaxSpawnDelay:0s,MaxNearbyEntities:1s,RequiredPlayerRange:16s,SpawnPotentials:[{Weight:1,Entity:{id:"bat"}}]}- For first spawner
- Make it switch to the SpawnPotentials
/blockdata ~ ~-1 ~ {SpawnCount:1b}- Right click with a creeper spawn egg
- For the second spawner
- Inspect the NBT data
/blockdata ~ ~-1 ~ {}→ It shows "minecraft:creeper" as entry for the SpawnPotentials instead of "minecraft:bat"
The bug
Some actions in the game apply the same NBT object instance to multiple items, entities or tile entities. This means if you edit it for one of them you basically edit it for all of them.
This could in theory happen with non-NBT data as well, but at least in the current versions this is not the case because either:
- the data is stored in primitive types and therefor no objects are involved
- the data is provided in NBT format but then parsed and stored with objects; therefor no reference to the NBT data exists anymore
Some of the cases listed below might happen when the NBT data is read or written by entities or tile entities. The expected fix is however not to have them always create a copy because that would slow down saving and loading worlds. Instead the methods calling these methods should create a copy before respectively after.
The reason why this report contains a list of all cases, even the ones which are not affected, is to have an overview and make it easier to detect new cases in which this happens.
Actions
Affected key
Symbol Meaning Affected Not affected Currently not affected, but current behavior is listed as bug and therefor likely affected in the future List
Based on 1.11.2 decompiled using MCP 9.35 rc1
Last updated for 1.11.2
Likely incomplete
Action Affected Comment Affected method Pick block with NBT Currently happens client-side, but should happen server-side Copying items in Creative - - Crafting: Cloning books - - Crafting: Cloning banners - - Crafting: Cloning maps - Creating item in Creative with BlockEntityTag - Using item with EntityTag Dispenser, spawn eggs, armor stand... Item with BlockEntityTag placed - - Items from loottables Uses NBTTagCompound.merge which clones - Items from villagers - - Splitting item stacks - - Hopper (minecart) item actions - - Droppers transferring items - - Cleaning banner in cauldron - - Cleaning leather armor in cauldron Even in Creative stack is replaced and water level reduced, not the case with banners, see MC-114105 Putting item on armor stand - - Using firework - - Putting item in item frame Only cloned when not empty, but even if empty set as item Putting chest on donkey or mule Entity does not store item data but only boolean, see MC-91005- Putting saddle on pig Entity does not store item data but only boolean, see MC-91005- Dispenser / dropper dropping item - - Dispenser placing player skull GameProfile is read and stored - Dispenser shooting tipped arrow Potion effects are read and stored - Dispenser throwing splash or lingering potion - - Dispenser equipping armor (including pumpkin, elytra and skull) - - Dispenser playing shulker box - - /clone See paragraph "How to reproduce" for reproduction /fill See paragraph "How to reproduce" for reproduction /entitydata Runs for each entity seperately and uses NBTTagCompound.merge which clones - /replaceitem entity Runs for each entity seperately - Structure blocks loading and saving See See MC-114030- How to reproduce
Some of these cases cannot be reproduced because other actions only override the affected data instead of modifying it, or other actions create a copy before you could try to reproduce them. Therefor here are only reproduction steps for some actions.
/clone
- Place a spawner
/setblock ~ ~ ~ mob_spawner default replace {SpawnData:{id:"armor_stand"},SpawnCount:0s,SpawnRange:0s,MinSpawnDelay:0s,MaxSpawnDelay:0s,MaxNearbyEntities:1s,RequiredPlayerRange:16s,SpawnPotentials:[{Weight:1,Entity:{id:"bat"}}]}- Clone the spawner
/clone ~ ~-1 ~ ~ ~-1 ~ ~2 ~-1 ~- For the cloned spawner
- Make it switch to the SpawnPotentials
/blockdata ~ ~-1 ~ {SpawnCount:1b}- Right click with a creeper spawn egg
- For the original spawner
- Inspect the NBT data
/blockdata ~ ~-1 ~ {}→ It shows "minecraft:creeper" as entry for the SpawnPotentials instead of "minecraft:bat"
/fill
- Fill in spawners
/fill ~1 ~ ~ ~2 ~ ~ mob_spawner default replace {SpawnData:{id:"armor_stand"},SpawnCount:0s,SpawnRange:0s,MinSpawnDelay:0s,MaxSpawnDelay:0s,MaxNearbyEntities:1s,RequiredPlayerRange:16s,SpawnPotentials:[{Weight:1,Entity:{id:"bat"}}]}- For first spawner
- Make it switch to the SpawnPotentials
/blockdata ~ ~-1 ~ {SpawnCount:1b}- Right click with a creeper spawn egg
- For the second spawner
- Inspect the NBT data
/blockdata ~ ~-1 ~ {}→ It shows "minecraft:creeper" as entry for the SpawnPotentials instead of "minecraft:bat"
The bug
Some actions in the game apply the same NBT object instance to multiple items, entities or tile entities. This means if you edit it for one of them you basically edit it for all of them.
This could in theory happen with non-NBT data as well, but at least in the current versions this is not the case because either:
- the data is stored in primitive types and therefor no objects are involved
- the data is provided in NBT format but then parsed and stored with objects; therefor no reference to the NBT data exists anymore
Some of the cases listed below might happen when the NBT data is read or written by entities or tile entities. The expected fix is however not to have them always create a copy because that would slow down saving and loading worlds. Instead the methods calling these methods should create a copy before respectively after.
The reason why this report contains a list of all cases, even the ones which are not affected, is to have an overview and make it easier to detect new cases in which this happens.
Actions
Affected key
Symbol Meaning Affected Not affected Currently not affected, but current behavior is listed as bug and therefor likely affected in the future List
Based on 1.11.2 decompiled using MCP 9.35 rc1
Last updated for 1.11.2
Likely incomplete
Action Affected Comment Affected method Pick block with NBT Currently happens client-side, but should happen server-side Copying items in Creative - - Crafting: Cloning books - - Crafting: Cloning banners - - Crafting: Cloning maps - Creating item in Creative with BlockEntityTag - Using item with EntityTag Dispenser, spawn eggs, armor stand... Item with BlockEntityTag placed - - Items from loottables Uses NBTTagCompound.merge which clones - Items from villagers - - Splitting item stacks - - Hopper (minecart) item actions - - Droppers transferring items - - Cleaning banner in cauldron - - Cleaning leather armor in cauldron Even in Creative stack is replaced and water level reduced, not the case with banners, see MC-114105 Putting item on armor stand - - Using firework - - Putting item in item frame Only cloned when not empty, but even if empty set as item Putting chest on donkey or mule Entity does not store item data but only boolean, see MC-91005- Putting saddle on pig Entity does not store item data but only boolean, see MC-91005- Dispenser / dropper dropping item - - Dispenser placing player skull GameProfile is read and stored - Dispenser shooting tipped arrow Potion effects are read and stored - Dispenser throwing splash or lingering potion - - Dispenser equipping armor (including pumpkin, elytra and skull) - - Dispenser playing shulker box - - /clone See paragraph "How to reproduce" for reproduction /fill See paragraph "How to reproduce" for reproduction /entitydata Runs for each entity seperately and uses NBTTagCompound.merge which clones - /replaceitem entity Runs for each entity seperately - Structure blocks loading and saving See SeeMC-114030- How to reproduce
Some of these cases cannot be reproduced because other actions only override the affected data instead of modifying it, or other actions create a copy before you could try to reproduce them. Therefor here are only reproduction steps for some actions.
/clone
- Place a spawner
/setblock ~ ~ ~ mob_spawner default replace {SpawnData:{id:"armor_stand"},SpawnCount:0s,SpawnRange:0s,MinSpawnDelay:0s,MaxSpawnDelay:0s,MaxNearbyEntities:1s,RequiredPlayerRange:16s,SpawnPotentials:[{Weight:1,Entity:{id:"bat"}}]}- Clone the spawner
/clone ~ ~-1 ~ ~ ~-1 ~ ~2 ~-1 ~- For the cloned spawner
- Make it switch to the SpawnPotentials
/blockdata ~ ~-1 ~ {SpawnCount:1b}- Right click with a creeper spawn egg
- For the original spawner
- Inspect the NBT data
/blockdata ~ ~-1 ~ {}→ It shows "minecraft:creeper" as entry for the SpawnPotentials instead of "minecraft:bat"
/fill
- Fill in spawners
/fill ~1 ~ ~ ~2 ~ ~ mob_spawner default replace {SpawnData:{id:"armor_stand"},SpawnCount:0s,SpawnRange:0s,MinSpawnDelay:0s,MaxSpawnDelay:0s,MaxNearbyEntities:1s,RequiredPlayerRange:16s,SpawnPotentials:[{Weight:1,Entity:{id:"bat"}}]}- For first spawner
- Make it switch to the SpawnPotentials
/blockdata ~ ~-1 ~ {SpawnCount:1b}- Right click with a creeper spawn egg
- For the second spawner
- Inspect the NBT data
/blockdata ~ ~-1 ~ {}→ It shows "minecraft:creeper" as entry for the SpawnPotentials instead of "minecraft:bat"
![[Mod] Michael Wobst](../../../data/avatars/users/37868.png){kind=small}
relates to
relates to
relates to
![[Mojang] Nathan Adams](../../../data/assets/gravatar/dinnerbone.png){kind=small}
The bug
Some actions in the game apply the same NBT object instance to multiple items, entities or tile entities. This means if you edit it for one of them you basically edit it for all of them.
This could in theory happen with non-NBT data as well, but at least in the current versions this is not the case because either:
- the data is stored in primitive types and therefor no objects are involved
- the data is provided in NBT format but then parsed and stored with objects; therefor no reference to the NBT data exists anymore
Some of the cases listed below might happen when the NBT data is read or written by entities or tile entities. The expected fix is however not to have them always create a copy because that would slow down saving and loading worlds. Instead the methods calling these methods should create a copy before respectively after.
The reason why this report contains a list of all cases, even the ones which are not affected, is to have an overview and make it easier to detect new cases in which this happens.
Actions
Affected key
Symbol Meaning Affected Not affected Currently not affected, but current behavior is listed as bug and therefor likely affected in the future List
Based on 1.11.2 decompiled using MCP 9.35 rc1
Last updated for 1.11.2
Likely incomplete
Action Affected Comment Affected method Pick block with NBT Currently happens client-side, but should happen server-side Copying items in Creative - - Crafting: Cloning books - - Crafting: Cloning banners - - Crafting: Cloning maps - Creating item in Creative with BlockEntityTag - Using item with EntityTag Dispenser, spawn eggs, armor stand... Item with BlockEntityTag placed - - Items from loottables Uses NBTTagCompound.merge which clones - Items from villagers - - Splitting item stacks - - Hopper (minecart) item actions - - Droppers transferring items - - Cleaning banner in cauldron - - Cleaning leather armor in cauldron Even in Creative stack is replaced and water level reduced, not the case with banners, see MC-114105 Putting item on armor stand - - Using firework - - Putting item in item frame Only cloned when not empty, but even if empty set as item Putting chest on donkey or mule Entity does not store item data but only boolean, see MC-91005- Putting saddle on pig Entity does not store item data but only boolean, see MC-91005- Dispenser / dropper dropping item - - Dispenser placing player skull GameProfile is read and stored - Dispenser shooting tipped arrow Potion effects are read and stored - Dispenser throwing splash or lingering potion - - Dispenser equipping armor (including pumpkin, elytra and skull) - - Dispenser playing shulker box - - /clone See paragraph "How to reproduce" for reproduction /fill See paragraph "How to reproduce" for reproduction /entitydata Runs for each entity seperately and uses NBTTagCompound.merge which clones - /replaceitem entity Runs for each entity seperately - Structure blocks loading and saving See MC-114030- How to reproduce
Some of these cases cannot be reproduced because other actions only override the affected data instead of modifying it, or other actions create a copy before you could try to reproduce them. Therefor here are only reproduction steps for some actions.
/clone
- Place a spawner
/setblock ~ ~ ~mob_spawnerdefaultreplace {SpawnData:{id:"armor_stand"},SpawnCount:0s,SpawnRange:0s,MinSpawnDelay:0s,MaxSpawnDelay:0s,MaxNearbyEntities:1s,RequiredPlayerRange:16s,SpawnPotentials:[{Weight:1,Entity:{id:"bat"}}]}- Clone the spawner
/clone ~ ~-1 ~ ~ ~-1 ~ ~2 ~-1 ~- For the cloned spawner
- Make it switch to the SpawnPotentials
/blockdata ~ ~-1 ~ {SpawnCount:1b}- Right click with a creeper spawn egg
- For the original spawner
- Inspect the NBT data
/blockdata~ ~-1 ~{}
→It shows "minecraft:creeper" as entry for the SpawnPotentials instead of "minecraft:bat"/fill
- Fill in spawners
/fill ~1 ~ ~ ~2 ~ ~ mob_spawner default replace {SpawnData:{id:"armor_stand"},SpawnCount:0s,SpawnRange:0s,MinSpawnDelay:0s,MaxSpawnDelay:0s,MaxNearbyEntities:1s,RequiredPlayerRange:16s,SpawnPotentials:[{Weight:1,Entity:{id:"bat"}}]}- For first spawner
- Make it switch to the SpawnPotentials
/blockdata ~ ~-1 ~ {SpawnCount:1b}- Right click with a creeper spawn egg
- For the second spawner
- Inspect the NBT data
/blockdata ~ ~-1 ~ {}→ It shows "minecraft:creeper" as entry for the SpawnPotentials instead of "minecraft:bat"
The bug
Some actions in the game apply the same NBT object instance to multiple items, entities or tile entities. This means if you edit it for one of them you basically edit it for all of them.
This could in theory happen with non-NBT data as well, but at least in the current versions this is not the case because either:
- the data is stored in primitive types and therefor no objects are involved
- the data is provided in NBT format but then parsed and stored with objects; therefor no reference to the NBT data exists anymore
Some of the cases listed below might happen when the NBT data is read or written by entities or tile entities. The expected fix is however not to have them always create a copy because that would slow down saving and loading worlds. Instead the methods calling these methods should create a copy before respectively after.
The reason why this report contains a list of all cases, even the ones which are not affected, is to have an overview and make it easier to detect new cases in which this happens.
Actions
Affected key
Symbol Meaning Affected Not affected Currently not affected, but current behavior is listed as bug and therefor likely affected in the future List
Based on 1.11.2 decompiled using MCP 9.35 rc1
Last updated for 1.11.2
Likely incomplete
Action Affected Comment Affected method Pick block with NBT Currently happens client-side, but should happen server-side Copying items in Creative - - Crafting: Cloning books - - Crafting: Cloning banners - - Crafting: Cloning maps - Creating item in Creative with BlockEntityTag - Using item with EntityTag Dispenser, spawn eggs, armor stand... Item with BlockEntityTag placed - - Items from loottables Uses NBTTagCompound.merge which clones - Items from villagers - - Splitting item stacks - - Hopper (minecart) item actions - - Droppers transferring items - - Cleaning banner in cauldron - - Cleaning leather armor in cauldron Even in Creative stack is replaced and water level reduced, not the case with banners, see MC-114105 Putting item on armor stand - - Using firework - - Putting item in item frame Only cloned when not empty, but even if empty set as item Putting chest on donkey or mule Entity does not store item data but only boolean, see MC-91005- Putting saddle on pig Entity does not store item data but only boolean, see MC-91005- Dispenser / dropper dropping item - - Dispenser placing player skull GameProfile is read and stored - Dispenser shooting tipped arrow Potion effects are read and stored - Dispenser throwing splash or lingering potion - - Dispenser equipping armor (including pumpkin, elytra and skull) - - Dispenser playing shulker box - - /clone See paragraph "How to reproduce" for reproduction /fill Fixed, see MC-163953/entitydata Runs for each entity seperately and uses NBTTagCompound.merge which clones - /replaceitem entity Runs for each entity seperately - Structure blocks loading and saving See MC-114030- How to reproduce
Some of these cases cannot be reproduced because other actions only override the affected data instead of modifying it, or other actions create a copy before you could try to reproduce them. Therefor here are only reproduction steps for some actions.
/clone
- Place a spawner
/setblock ~ ~ ~ spawner{SpawnData:{id:"armor_stand"},SpawnCount:0s,SpawnRange:0s,MinSpawnDelay:0s,MaxSpawnDelay:0s,MaxNearbyEntities:1s,RequiredPlayerRange:16s,SpawnPotentials:[{Weight:1,Entity:{id:"bat"}}]}- Stand on top of the spawn and run the following command
/clone ~ ~-1 ~ ~ ~-1 ~ ~2 ~-1 ~- For the cloned spawner
- Make it switch to the SpawnPotentials (stand on top of it while running the command)
/data modify block ~ ~-1 ~ SpawnCount set value 1b- Right click the spawner with a creeper spawn egg
- For the original spawner
- Inspect the NBT data
/data get block ~ ~-1 ~ SpawnPotentials
/fill
Fixed by
MC-163953
The bug
Some actions in the game apply the same NBT object instance to multiple items, entities or tile entities. This means if you edit it for one of them you basically edit it for all of them.
This could in theory happen with non-NBT data as well, but at least in the current versions this is not the case because either:
- the data is stored in primitive types and therefor no objects are involved
- the data is provided in NBT format but then parsed and stored with objects; therefor no reference to the NBT data exists anymore
Some of the cases listed below might happen when the NBT data is read or written by entities or tile entities. The expected fix is however not to have them always create a copy because that would slow down saving and loading worlds. Instead the methods calling these methods should create a copy before respectively after.
The reason why this report contains a list of all cases, even the ones which are not affected, is to have an overview and make it easier to detect new cases in which this happens.
Actions
Affected key
Symbol Meaning Affected Not affected Currently not affected, but current behavior is listed as bug and therefor likely affected in the future List
Based on 1.11.2 decompiled using MCP 9.35 rc1
Last updated for 1.11.2
Likely incomplete
Action Affected Comment Affected method Pick block with NBT Currently happens client-side, but should happen server-side Copying items in Creative - - Crafting: Cloning books - - Crafting: Cloning banners - - Crafting: Cloning maps - Creating item in Creative with BlockEntityTag - Using item with EntityTag Dispenser, spawn eggs, armor stand... Item with BlockEntityTag placed - - Items from loottables Uses NBTTagCompound.merge which clones - Items from villagers - - Splitting item stacks - - Hopper (minecart) item actions - - Droppers transferring items - - Cleaning banner in cauldron - - Cleaning leather armor in cauldron Even in Creative stack is replaced and water level reduced, not the case with banners, see MC-114105 Putting item on armor stand - - Using firework - - Putting item in item frame Only cloned when not empty, but even if empty set as item Putting chest on donkey or mule Entity does not store item data but only boolean, see MC-91005- Putting saddle on pig Entity does not store item data but only boolean, see MC-91005- Dispenser / dropper dropping item - - Dispenser placing player skull GameProfile is read and stored - Dispenser shooting tipped arrow Potion effects are read and stored - Dispenser throwing splash or lingering potion - - Dispenser equipping armor (including pumpkin, elytra and skull) - - Dispenser playing shulker box - - /clone See paragraph "How to reproduce" for reproduction /fill Fixed, see MC-163953/entitydata Runs for each entity seperately and uses NBTTagCompound.merge which clones - /replaceitem entity Runs for each entity seperately - Structure blocks loading and saving See MC-114030- How to reproduce
Some of these cases cannot be reproduced because other actions only override the affected data instead of modifying it, or other actions create a copy before you could try to reproduce them. Therefor here are only reproduction steps for some actions.
/clone
- Place a spawner
/setblock ~ ~ ~ spawner{SpawnData:{id:"armor_stand"},SpawnCount:0s,SpawnRange:0s,MinSpawnDelay:0s,MaxSpawnDelay:0s,MaxNearbyEntities:1s,RequiredPlayerRange:16s,SpawnPotentials:[{Weight:1,Entity:{id:"bat"}}]}- Stand on top of the spawner and run the following command
/clone ~ ~-1 ~ ~ ~-1 ~ ~2 ~-1 ~- For the cloned spawner
- Make it switch to the SpawnPotentials (stand on top of it while running the command)
/data modify block ~ ~-1 ~ SpawnCount set value 1b- Right click the spawner with a creeper spawn egg
- For the original spawner
- Inspect the NBT data
/data get block ~ ~-1 ~ SpawnPotentials
/fill
Fixed by
MC-163953
![[Mod] j_p_smith](../../../data/avatars/users/92851.png){kind=small}
The bug
Cleaning leather armor and shulker boxes using a cauldron in Creative behaves like it does in Survival: The water level of the cauldron is lowered and the item is replaced.
Expected behavior
The expected behavior is that it acts like banners: Right clicking a cauldron only gives the player a new cleaned item (see MC-114104), and everything else remains unchanged.
How to reproduce
- Change your gamemode to Creative
/gamemode creative
- Place a cauldron with water
/setblock ~1 ~ ~ water_cauldron[level=3]
- Right click the cauldron with dyed leather armor
/give @p leather_chestplate{display:{color:0}}→
The color was removed from the leather armor and the water level of the cauldron was lowered
The bug
/data modify and /execute store seem to copy NBT by reference. For most NBT this has no effect, but for NBT in the tag tag of items, it results in a link between the two, where later modifying one affects the other (other examples in MC-114104).
How to reproduce
Get an item with NBT, summon a mob, and data modify your item into its hand:
/replaceitem entity @p weapon.mainhand diamond_sword{Damage:5}
/summon husk
/data modify entity @e[type=husk,sort=nearest,limit=1] HandItems[0] set from entity @p SelectedItem
/enchant @p sharpness
→ The husk's sword is enchanted as well.
This link will persist until either the destination or source is reloaded for any reason.
Additional test
Attached is a datapack that uses a jukebox to store a list of data, and a command block used to compare two strings. Using a temporary list, the object that contains the matching string within the jukebox's RecordItem tag also contains an ID tag which is type int. After finding the correct object, the item's Item.tag.ID is set from here, then to show the bug the ID of the source is changed to 42 (from 6).
Expected behavior: The item's ID tag is set to 6.
Actual behavior: The item's ID tag is set to 42.
To test, start a new world and go to 0,0 before loading the datapack. Then run /function lookup:test
Kind of a duplicate of MC-114104, but I will leave this report open since the other one is not up to date.
Hi,
I've expirenced simmilar issues that MC-114104 and MC-163953 describe.
Hoewer, this issue is not present in 1.17.x. Perhaps the spawner syntax change broke something.
How to reproduce:
1. Launch minecraft in versions 1.18 and above
2. Run
/fill ~1 ~ ~ ~1 ~1 ~ minecraft:spawner{SpawnData:{entity:{id:"minecraft:armor_stand"}},RequiredPlayerRange:0s,MaxNearbyEntities:0s}
3. Run
/data modify block ~1 ~ ~ SpawnData.entity.id set value "minecraft:bat"
4. Observe how the mob inside the bottom spawner changes to a bat, and the top spawner is still an armorstand
5. Run
/data get block ~1 ~1 ~ SpawnData.entity.id
It returns "minecraft:bat"! Notice that client is still displaying an armor stand.
Once again, it works only in 1.18 and above
once upon a time, I recall that doing entitydata on a ThrownPotion to change the potion details would cause the potion item in my inventory to also change, which sounds like a similar thing (have not tried to repro now)
Brian McNamara, you are thinking about
MC-92191(already fixed)Unable to reproduce for /fill and /clone as of 20w07a.
edit: /clone still reproducible
Can confirm in 1.20.1.