[MC-56793] Dropper facing other dropper doesn't transfer items if redstone source is on top

The bug

Dropper facing other dropper doesn't transfer items if redstone source is on top

To reproduce

Place two droppers facing each other
Places some blocks in one dropper
Place any redstone source (e.g. lever) on top of the loaded dropper
Flip the switch several times -> Target dropper is empty
Remove the switch from top and place it besides the loaded dropper
Flip the switch several times -> Target dropper has received blocks

Demonstration video: http://youtu.be/VNqOA12Kyj8

Related issues

duplicates

MC-11193 The order in which powerable blocks (e.g. redstone dust blocks) along a wire are powered or de-powered is not clearly defined and causes a non-deterministic behavior for redstone contraptions

Attachments

Comments

migrated 2014-06-16T18:16:38Z

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kumasasa 2014-06-16T18:38:34Z

Confirmed.

kumasasa 2014-06-16T18:45:18Z

Strongly related (if not duplicating) MC-10174

migrated 2014-06-16T22:02:52Z

This behaviour is dependant on the order in which the redstone or the lever updates the 2 droppers. A dropper is a solid block, and therefore a level or redstone directly on top of it also powers the other dropper, which will in half of the possible locations make the item ping pong back and forth. powering the dropper through a block will work fine.

migrated 2014-12-14T19:13:39Z

This isn't necessarily a bug. A button, lever, etc. will power all blocks adjacent to it (or within range of it). This would probably cause dropper 1 to hand the item to dropper 2, but then get it right back because it's powered, possibly a little later (maybe a fraction of a second). The developers could maybe set up Minecraft so it has all the adjacent blocks powered at the same time and so the droppers don't play ping pong.
I could be wrong with the later powering thing, so please don't quote me on that.

galaxy_2alex 2014-12-20T22:06:03Z

Is this still a concern in the current Minecraft version? If so, please update the affected versions in order to best aid Mojang ensuring bugs are still valid in the latest releases/pre-releases. If this has been done, we can reopen the issue.

Keep in mind that the "Resolved"-Status on this ticket just means "Answered", and that we are waiting for further information on whether this issue still exists or not. We will reopen it as soon as the requested information has been delivered.

migrated 2017-02-14T15:12:19Z

Ticket resolved as incomplete, because no answer in a reasonable amount of time (1+ year), if it still happens, please update the ticket.

migrated 2017-02-15T15:06:59Z

Why was this bug reopened? I thought we determined that there's some sense behind it.

migrated 2017-02-15T15:19:56Z

The ticket never got resolved, only as awaiting response and incomplete due to no response for 1+ year, but it got updated now.

SuperGeniusZeb 2017-06-15T01:35:09Z

Resolving as a duplicate of MC-11193.

migrated 2017-06-15T10:26:43Z

I don't believe that this report is necessarily duplicating MC-11193.
The reason for this is that MC-11193 addresses the order in which connected pieces of redstone dust change state, whereas this report (indirectly) addresses the order in which a single piece of redstone dust updates adjacent blocks. This is a fundamental difference which must be made clear.