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MCPE-38963

Hoppers and hopper minecarts not picking from multiple item types when collecting

Updated description by @unknown June 1, 2020

Steps to reproduce

(These steps are automated in

[media]

.)

  1. Put 1 stackable item in each slot of a hopper/hopper-minecart.

  2. Drop a different item on the hopper/hopper-minecart.

  3. Drop an item that matches an item from step 1 on the hopper/hopper-minecart.

Expected result

The hopper/hopper-minecart collects/sucks the matching item.

Actual result

The hopper/hopper-minecart will not collect/suck the matching item until the non-matching item is removed.

Note: test analysis provided in this comment.
Code analysis corroborating testing in this comment.


Original summary
Hoppers not picking from multiple item types
Original description
When item sorting hoppers (as shown in the screenshot to sort redstone) has multiple item types (with the selected item type included) pass above it, the hopper will occasionally fail to suck in the selected item type from the group.

Steps to Reproduce:

  1. Construct a single item sorter with a water stream as depicted in the screenshot with the top hopper set to sort an item type

  2. Confirm the top hopper only accepts the chosen item type

  3. Block the water steam

  4. Drop several of the chosen item type

  5. Drop several of another item type

  6. Unblock the water stream

Observed Results:

All items (included the chosen item type) pass over the hopper.

Expected Results:

Hopper sucks in the selected item type and the rest flow by.

This does happen most of the time

Screenshots/Videos Attached: Yes

Video of occurrence

Device: Asus ZenFone AR

Linked issues

Attachments

Comments 47

Auldrick

Can you reproduce this issue without breaking ice above the selection hopper? How about without breaking ice next to it, either?

There's a lot happening in the block above the hopper in your video. The breaking particle animation has to run, the flowing water has to be spawned to replace it, and then the redstone dust has to flow into and (when the timing is just right) out of that block. Breaking the ice is a world change event that happens asynchronously with the redstone tick clock, which could explain why it works as expected most of the time. When the timing is just right, the hopper's checks for an item might happen just outside the window of opportunity to find the item. In that case, this would be another example of MCPE-15793. But if the problem still occurs after the asynchronous activity is moved father away, this would more likely be a new issue.

 

Annie Ellico

Distance from user inputs added

 

Use of slabs and trapdoor hitbox (MCPE-13451) to limit the item's height whilst keeping most of it above the hopper

[Mojang] Mega_Spud (Jay)

Attached test world for reproduction:

[media]

USERcrosbyman64

Shouldn't the top hopper be facing the comparator AND have the same items inside said hopper?

Tal Melamed

(Tested before reported - from 'Technical Bugs List' https://docs.google.com/document/d/1nziKYzCr4pBdCRj2gIMlfr9MVdWHd6HyafdiBHx9F0c/edit)

This issue happens in 1.14.30 hotfix and 1.15.0.51 also.

37 more comments
Mr. K

Affects 1.18.2. This bug continues to have major impact on technical play, specifically for trying to sort the output from a farm that outputs large amounts of numerous item types (like moss farms or piglin trading)

blinkage

This behavior also affects 1.19.10.03 just like in the comments and examples above.

Tal Melamed

1.19.20 too...

xRsBuiltx

As mentioned, still current in 1.19.20.  Ive made a contraption to simulate exactly whats going on. I put it all into a small .mcworld file. You can find that here https://www.mediafire.com/file/g1b69ggnefzpam1/Brokenhoppers.mcworld/file  If you need me to make a new bug report for this, Let me know and ill be happy too! Thank you! -Rs. 


Reply from @unknown: there is already a test world linked in the description at the top of this report.

xRsBuiltx

Yes, Options are always good though! I know some bugs can be hard to replicate. 🙂 Thank you! 

Annie Ellico

(Unassigned)

308051

Confirmed

Multiple

Android 7.0

1.17.30.25 Beta, 1.17.10, 1.17.0.54 Beta, 1.17.0.50 Beta, 1.16.230.50 Beta, ..., 1.18.2 Hotfix, 1.18.12 Hotfix, 1.19.10, 1.19.20, 1.19.31 Hotfix

1.19.60.24 Preview, 1.19.60

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