[MC-197348] Piston heads occasionally appear twice in certain piston setups

The bug

Occasionally, during the retraction of pistons, the piston head appears twice. This is not consistently an issue, but it still happens once in a while.

How to reproduce

Build a flying machine as shown in the pictures below:

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Then, update the observer on the bottom to activate the flying machine.

Notice that on occasion, one of the pistons in the flying machine shows with two piston arms. This is a difficult bug to reproduce; I used a screen recorder to be able to see the double extension (as I can slow down the recording using it).

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A screenshot with my F3 debug menu is attached. I can also confirm on my other computer, for which you can see the F3 debug menu on MC-194175.

Linked issues

relates to 1

MC-197218 Piston arm appears twice during retraction in some mechanisms Resolved

Attachments

Screen Shot 2020-08-07 at 10.56.45 AM.png

Comments 4

NeunEinser 2020-08-07T15:51:00Z

Different from MC-197218, as I could not reproduce it the same way in pre3 anymore.

NeunEinser 2020-08-07T15:56:50Z

Testing further reveals that the same contraption as shown in MC-197218 still reproduces the bug, it's just seemingly random now and it is somewhat rare now, but the issue seems to still exist.

NeunEinser 2020-08-07T16:06:02Z

It seems like it might have to do with lag. Increasing the render distance to 32 seems to make it more consistent on my machine.

[Mod] markderickson 2020-08-07T16:15:06Z

Hi there!

I was thinking that too. I don't use a particularly fast computer for my testing, and while using the screen recorder, even more lag is present, so that's probably the reason why I could see the bug more while using the screen recorder.