MCPE-116576Dropper update order is affected by observers
In regular conditions, a hard powered dropper will update before a soft powered dropper in the same gametick. That mean that in pic 1, if an item is placed in the bottom dropper, it will end up in the top dropper when the lever is flicked. However, when an observer is detecting this top dropper, , the update order will change, and an item placed in the bottom dropper will be shot out when the lever is flicked. This happens in various situations, and breaks common T flip flop designs, as well as making other circuits very fragile to their environnement. This also allows wireless redstone in a single chunk.
How to reproduce :
Follow steps described above and shown in the pictures.
Linked Issues
Created Issue:
Dropper update order is affected by observers
How to reproduce :
Follow steps described above and shown in the pictures.
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![[Mod] GoldenHelmet](../../../data/avatars/users/18951.svg){kind=small}
In regular conditions, a hard powered dropper will update before a soft powered dropper in the same gametick. That mean that in pic 1, if an item is placed in the bottom dropper, it will end up in the top dropper when the lever is flicked. However, when an observer is detecting this top dropper, , the update order will change, and an item placed in the bottom dropper will be shot out when the lever is flicked. This happens in various situations, and breaks common T flip flop designs, as well as making other circuits very fragile to their environnement. This also allows wireless redstone in a single chunk.
How to reproduce :
Follow steps described above and shown in the pictures.
In regular conditions, a hard powered dropper will update before a soft powered dropper in the same gametick. That mean that in pic 1, if an item is placed in the bottom dropper, it will end up in the top dropper when the lever is flicked. However, when an observer is detecting this top dropper, , the update order will change, and an item placed in the bottom dropper will be shot out when the lever is flicked. This happens in various situations, and breaks common T flip flop designs, as well as making other circuits very fragile to their environnement. This also allows wireless redstone in a single chunk.
How to reproduce :
Follow steps described above and shown in the pictures.
relates to
![[Mojang] Mega_Spud (Jay Wells)](../../../data/avatars/users/92696.png){kind=small}
relates to
![[Bot] Arisa](../../../data/avatars/users/43007.png){kind=small}
The player as same problem: MCPE-116576
I think this is actually a closer match to MCPE-16208, but MCPE-116576 and MCPE-157060 describe specific manifestations of the same underlying issue, namely: dropper update order is neither fully random nor fully deterministic. As a result, builds that work when built once may not work when rebuilt in a different place or when other redstone components or blocks that use pending ticks are placed or removed in the same chunk.
This issue can also be seen if you power droppers with a redstone dust line, then power them with observers, both with no delay between activations, the update order will be different. An easy visualization of this is to do the say command in command blocks, and have them ordered to say numbers 1-15. Then, power these command blocks with a redstone dust line soft powering them. The numbers will appear in a certain order. Next soft power the command blocks with observers, no delay in between each observer. The order of the list of numbers the commands blocks say are different when observers are used. This issue is also present with droppers and other consumers.
Yeah, it happens in many different scenarios, the one with obs detecting the dropper is just the easiest to reproduce
Thank you for your report!
However, this issue has been temporarily closed as Awaiting Response
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Cleaning up old tickets: This ticket had been set to 'Awaiting Response', but has not received a response from the reporter (~3 months+) so is being closed as Incomplete. If you feel this is still a valid issue then please comment, or create a new ticket following the Issue Guidelines which includes steps to reproduce the problem.
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