[MC-10708] Pistons don't respond to 0 redstone tick pulses at certain occasions Created: 02/Mar/13  Updated: 25/Jun/18  Resolved: 14/Oct/14

Status: Resolved
Project: Minecraft: Java Edition
Component/s: None
Affects Version/s: Snapshot 13w09c, Snapshot 13w10a, Snapshot 13w10b, Minecraft 1.5, Minecraft 1.5.1, Minecraft 1.5.2, Snapshot 13w18c, Snapshot 13w19a, Minecraft 1.7.10, Minecraft 14w30b, Minecraft 14w30c, Minecraft 14w31a, Minecraft 14w32a, Minecraft 14w32b, Minecraft 14w32c, Minecraft 14w32d, Minecraft 14w33c, Minecraft 14w34a, Minecraft 14w34b, Minecraft 14w34c, Minecraft 14w34d, Minecraft 1.8-pre1, Minecraft 1.8-pre2, Minecraft 1.8-pre3, Minecraft 1.8
Fix Version/s: None

Type: Bug
Reporter: Steve Bob Assignee: [Mojang] Searge (Michael Stoyke)
Resolution: Works As Intended Votes: 15
Labels: piston, redstone, unreliable
Environment:

Windows Vista, Windows 8


Attachments: JPEG File 1.jpg     JPEG File 2.jpg     PNG File 2014-07-26_16.15.33.png     PNG File 2014-07-26_16.15.36.png     PNG File 2014-07-26_16.15.54.png     PNG File 2014-07-26_16.15.56.png     PNG File 2014-07-26_16.19.59.png    
Issue Links:
Duplicate
is duplicated by MC-11602 Piston monostable not working in 1.5 ... Resolved
CHK:
Confirmation Status: Confirmed

 Description   

When a piston is powered with a 0 redstone tick pulse (or a half redstone tick pulse, meaning it's powered for only 1 game tick but not a full redstone tick), it only gives a pulse at some occasions, as it can be seen in the screenshots.

To reproduce:
Make a monostable circuit (a sticky piston facing up with a block on top and a repeater pointing at the block), put a piston with a block on its head, next to the monostable circuit (as it can be seen in the screenshots), and power it.



 Comments   
Comment by RedCMD [ 25/Jun/18 ]

This bug is not due to pistons. 

Tho its hard to test without them
Its due to block update order XYZ

So the X-piston checks for power and fires
Then the Y-piston checks for power and fires  (which moves the block)

Then Z-piston checks for power (sees no power due to the block being moved) and doesn't do anything

If the block update order was changed from XYZ to XZY or YXZ there would be way less Directional stuff

Comment by KingSupernova [ 10/Jul/15 ]

Mojang seems to have decided that the purpose of pistons is to have as many inconsistent behaviors as possible. I don't think any piston-related reports are going to be fixed any time soon.

Comment by someone314 [ 09/Jul/15 ]

please fix this. it breaks more redstone contraptions than it fixes

Comment by Steve Bob [ 17/Oct/14 ]

Leaving the bug like that will also have something broken.

Comment by munkkiukko [ 17/Oct/14 ]

Maybe fixing that would break something

Comment by Steve Bob [ 15/Oct/14 ]

I'm sorry, but this bug being flagged as "Works as intended" will leave pistons buggy, as they've always been. Sincerely, it feels like this bug wasn't even read by Mojang before being flagged by that.

Comment by DicoTheRedstoner [ 31/Aug/14 ]

An easy way to explain this is using 'microticks'.
Each piston which retracts, causes a delay of 1 microtick, this is often seen as 'instant'.
I believe a gametick goes on when all micro ticks have processed and when 0.05 seconds have passed. When you use this monostable, it depends on which piston is updated first.
When you add a microtick, by pushing a block forward that then lets redstone power through, powering the lower 'monostable' piston which is moved above, it will be reliable. It just forces the correct order.

Comment by Steve Bob [ 27/Aug/14 ]

Sand generators were already fixed.
This change was said to be made with the intention of pistons becoming more "reliable", but it doesn't work reliably as you can see in the screenshots in which some pistons get powered and others not, even when getting the same pulse; as well as the title and the description say.

Comment by Steve Bob [ 26/Jul/14 ]

Added more screenshots, updated the affected versions and changed the title as well as the description, explaining better what happens.

Comment by [Mod] Ezekiel (ezfe) [ 26/Jul/14 ]

Is this still a concern in the latest Minecraft version 14w30c? If so, please update the affected versions in order to best aid Mojang ensuring bugs are still valid in the latest releases/pre-releases.

Comment by Kenny Lau [ 12/Mar/13 ]

It seems that the pulse is actually 0.5 tick.

Comment by yut951121 [ 03/Mar/13 ]

Seems like piston monostable circuit's output is shorter than 1 tick and pistons not responding it.

Comment by yut951121 [ 03/Mar/13 ]

This is really weird because with some specific setup, pistons respond. See http://youtu.be/J12aW0hmT98

Comment by Tails [ 02/Mar/13 ]

Confirmed.

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