[MC-26919] Adjacent Command Blocks in line get powered in a pseudo-random way

If you put a line of adjacent command blocks to be executed at the same tick, they are not activated in the powering order, firstly powered (strongest power) firstly executed, they are instead powered in some situations that seems to be unique, here what I've seen :

the same system in two different worlds at the same position does not change activation order, should does like now.
the same system made at the same position, with block at the same position but with blocks placed in a different order does not change the activation order, should does like now.
the same system in two different position (in the same chunk) change the activation order, should not.
the same system at the same position depending to chunks but in different chunks change the activation order, should not.
the same system with a different rotation change the activation order, should not.
the same command blocks at the same position but with redstone source at a different position change the activation order.

If we additionnaly put command blocks around the directly powered block, they should be activated depending to their relation with the directly powered blocks (always top > north > south > east > west > bottom for example)

Linked issues

duplicates 1

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 Open

Attachments

crash-2013-07-25_15.19.49-client.txt

Comments 14

kumasasa 2013-07-23T20:10:44Z

Please force a crash by pressing F3 + C for 10 seconds while ingame and attach the crash report here.

Yoann Petremann 2013-07-25T13:23:03Z

This crash report has been manually triggered, not triggered at the same time the screenshot was taken, but the same world, position and condition has been reproduced.

Anon Ymus 2013-07-28T02:24:05Z

That's fine. Please attach it.

kumasasa 2013-07-28T06:52:28Z

Confirmed.

Nathan Gilbert 2013-09-17T00:19:07Z

See here (http://www.youtube.com/watch?v=Zt7YEYdx6RE) for an explanation of what is likely causing your issue. Redstone is not updated in a systematic fashion like other block updates are, but instead utilizes a HashSet of locations that need updating. This set is highly dependant on the coordinates of each and every block in the system, so translating or rotating the wiring would cause the set to be iterated in a different order.

4 more comments

Ezekiel 2014-07-26T18:51:46Z

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.

galaxy_2alex 2014-10-25T18:52:04Z

Is this still a concern in the current Minecraft version 1.8.1 Prerelease 3 / Launcher version 1.5.3 or later? If so, please update the affected versions in order to best aid Mojang ensuring bugs are still valid in the latest releases/pre-releases.

Panda4994 2014-10-30T23:05:55Z

@Kumasasa
Yes, it's the same as MC-11193.
It's caused by redstone updates being organized using a hash map which makes the update order seemingly random.

It still is this way in 1.8-pre3 as MC-11193 says. (I also tested it.)

Nathan Gilbert 2014-10-30T23:39:20Z

This issue should probably be marked as a feature request if Mojira supports that. The issue isn't a simple bug, but fixing it (assuming Mojang considers it broken) would require a significant rewrite to how redstone is calculated. I'm assuming it will be noted in a changelog if it ever does get fixed because as I say, it's not a simple undertaking. This behaviour has existed as long as redstone has, so I wouldn't be suprised if it's a "Won't Fix", but might be nice to get some word from Mojang if it's something they want to revisit.

kumasasa 2014-10-31T06:56:55Z

Marking this as duplicate of MC-11193.

Feature requests aren't tracked on this site.