[MCPE-14710] Observer block doesn't detect all block state changes Created: 04/Jun/16  Updated: 20/Jan/20  Resolved: 31/Jul/17

Status: Resolved
Project: Minecraft (Bedrock codebase)
Component/s: None
Affects Version/s: 0.15.0 Beta build 1, 0.15.0, 0.15.1 Beta 1, 0.15.1, 0.15.2, 0.15.3, 0.15.6, 0.15.7, 0.15.90.7, 0.15.10, 0.15.90.8, 0.16.0, 0.16.1, 0.17.0.1, 0.16.2, 1.0.0.0, 1.0.0.1, 1.0.0, 1.0.2, 1.0.3, 1.0.4.0, 1.0.4.1, 1.0.4.11, 1.0.5.13, 1.0.6.0, 1.0.5.54, 1.1.0.0, 1.1.0.1, 1.0.6.52, 1.1.0.4, 1.0.7.0, 1.1.0.9, 1.1.0.55, 1.1.1.0, 1.1.3.1, 1.1.3.52
Fix Version/s: 1.2.0.2

Type: Bug
Reporter: Victor Camarillo
Resolution: Fixed Votes: 23
Labels: block-update, observer, redstone

Attachments: JPEG File ScreenShot 166.JPG     JPEG File observer.jpg    
Issue Links:
Duplicate
is duplicated by MCPE-15477 Placing redstone dust doesn't cause a... Resolved
is duplicated by MCPE-15593 BUD detector doesn't detect several s... Resolved
is duplicated by MCPE-15649 Observer doesn't consider BUD from bu... Resolved
is duplicated by MCPE-15971 Observer Block Resolved
is duplicated by MCPE-16289 Observer block doesn´t give of a puls... Resolved
is duplicated by MCPE-16640 Observer wont detect certain things Resolved
is duplicated by MCPE-17499 Observers do not detect updates of th... Resolved
is duplicated by MCPE-21762 Observers do not detect torch burnout Resolved
is duplicated by MCPE-22213 Observer Doesn't Detect Placement Of ... Resolved
Relates
relates to MCPE-61978 Observer doesn't detect several block... Open
relates to MCPE-11555 Fence gates has no sound when activat... Resolved
Confirmation Status: Confirmed
Platform: Phone - Android - Samsung Other (Specify in description)
CHK:
ADO: 31509

 Description   

We all know that when redstone ore is being mine, step on or just being touch it start glowing which is a block update but the observer block doesn't read this block update which means that the observer doesn't give off a redstone signal and yes i do know how the observer block work. But it does work with other block update but not when the redstone ore block is being updated so it can glow. My phone is a samsung galaxy s4.

EDIT by SuperGeniusZeb: This bug is not with the observer, which is working fine. The bug is actually with all of the blocks/events listed below, because they actually don't cause block updates at all.

List of things not detected by Observer (Keep updated):

  1. Redstone ore glowing
  2. Fence Gates activated by redstone.
  3. Change the daylight sensor.
  4. Redstone torches changing state
  5. Growing Cocoa Pods
  6. Lighting Nether Portal
  7. Powering Activator Rails
  8. Placing Redstone Dust
  9. Piston activating (the body, not the head)
  10. Snow Layer Created by Snow Golem
  11. Water/lava flowing (referring to the liquid that is already there not receiving a block update when it spreads)

Update by nighter
This bug has been reported to our internal bug tracker for further testing and a fix. It is scheduled to be fixed in one of the future updates (no specific date can be provided).
Please avoid duplicated comments. Post only NEW information regarding this bug.



 Comments   
Comment by John Nicholl [ 28/Nov/17 ]

Observers still not detecting Redstone Ore activation on 1.2.5. Why no fix yet? this was reported a year ago!

Comment by JavaC0der [ 07/Apr/17 ]

The lava/water source flowing can't be detected either.
I was trying to build this: https://www.youtube.com/watch?v=myDz5EwyWHw
(Yes, it also uses quasi-connectivity, but that can be easily changed).

Comment by Zeb [ 21/Nov/16 ]

Revised title to be more accurate. (The observer DOES detect all block updates... some blocks simply aren't causing block updates when they should.)

Comment by [Mojang] Mega_Spud (Jay Wells) [ 21/Nov/16 ]

Added snow layer created by snow golem to the list in the description.

(Snow layers placed by a player are detected)

Comment by Zeb [ 13/Oct/16 ]

ClassyElm123 Java edition bugs should be reported on the Java edition bugtracker. The MCPE bugtracker only tracks MCPE bugs.

https://bugs.mojang.com/browse/MC

Comment by ClassyElm [ 12/Oct/16 ]

You might want to add Minecraft Java version as an affected Minecraft edition because of the addition of observer blocks in 16w39a. A very similar glitch occurs there. When opening and closing a door or fence gate, the observer does not detect this block update. I'm sure there are other block updates not detected, but that is just one.

Comment by Zeb [ 05/Oct/16 ]

thebigsmileXD: The observer can be made to output strong power and be coded just like the Java edition observer, but it is important to note that they will still act differently, since block/redstone updates happen differently in the 2 editions. For example, in the Java edition, if you point a repeater into a block and power the repeater, the repeater will update the block, and an observer can detect the block being updated. Actually, the repeater will update the spot in front of it regardless of whether or not there is even a block. And in fact, it actually causes updates on the blocks adjacent to the block in front of it. So the repeater causes at least 6 block updates, not counting itself updating.

In MCPE, repeaters cause no updates (except on themselves) unless there is a redstone component in front of them. If you point a repeater into a block and put redstone dust on the other end, the repeater will cause the redstone dust to turn on, causing a block update, but the block in-between will not be updated, as the repeater causes the redstone dust to update directly, and the redstone dust, in turn, doesn't update anything except itself, as there are no other components near it that it can power.

So because of this, observers in the Java edition will respond to a lot more things than MCPE observers, because the Java edition redstone components cause more redstone updates (most of which are unnecessary and cause lag) than the MCPE redstone components, which remember the location of nearby components and update them directly, rather than flooding the adjacent blocks with unneeded updates.

So even if observers were changed to output strong power like in the Java edition, you wouldn't be able to chain them with air blocks in between each observer, because the air blocks would never get updated by the observers output. I'm also not sure if MCPE observers themselves get updated when they're activated. If they do, then you could chain them by placing them in front of each other, but if they don't, then that would still not work.

It is also currently undetermined as to how many of the Java edition observer behaviors are intended, so its a bit too early to say what would need to be changed on which edition.

But all of that is somewhat unrelated to this bug, which is really misnamed. The observer block IS reading all block updates.

The real issue is that the things listed in this bug report don't cause block updates, even though they should. So this is not an observer bug... this is a bug with multiple blocks not causing block updates when they should.

rplatham Could you please change the name of this bug to something like "Some blocks don't cause block updates when they should" or something like that? I've tested these instances with the floating-water-block-update-trick/test and I can confirm that the observer is working fine... it is the other blocks that aren't causing any updates.

Comment by inxomnyaa [ 05/Oct/16 ]

What about making them act like in PC? (except for the diagonal quasiconnectivity)

Comment by Zeb [ 05/Oct/16 ]

Affects 0.15.10. (Tested on Windows 10.)

Comment by rplatham [ 27/Sep/16 ]

Fixed (err the description, not the whole bug!), as per zebulanstanphill@gmail.com.

Comment by Zeb [ 19/Sep/16 ]

Could a moderator please update the description to reflect the fact that this bug is now fixed for doors and weighted pressure plates, and also the fact that placing spawn eggs in a monster spawner should NOT cause a block update and therefore the bug doesn't apply to that block? EDIT: Thanks, but you forgot to remove the top halves of doors from the list.

Comment by Zeb [ 16/Sep/16 ]

Affects 0.16.0 Beta Build 4 (AKA 0.15.90.7).

Comment by [Mojang] Adrian Östergård [ 14/Sep/16 ]

This bug has been reported to our internal bug tracker for further testing and a fix. It is scheduled to be fixed in one of the future updates (no specific date can be provided).

Comment by Zeb [ 03/Sep/16 ]

I can confirm that fence gates activated by redstone, switching the orientation of rails, and inverting redstone torches all do NOT cause block updates. Therefore, this bug is incorrect as it is a bug with the blocks themselves, NOT the Observer.

Comment by Zeb [ 03/Sep/16 ]

Fixed for weighted pressure plates and doors in 0.15.90.2. (Tested on Pocket Edition.) I think the remaining cases may all be due to the blocks themselves not causing updates, and if so (if there isn't already), there should be a bug report for all the instances of blocks not causing block updates when they should. Except for placing a spawn egg in a spawner, because that only changes NBT data and doesn't cause an update on the Java edition either.

I will try and check using the melting-ice-into-floating-water trick to check if the remaining cases even cause block updates at all.

Comment by inxomnyaa [ 27/Jun/16 ]

To remind you: My issue has images attached that explain HOW to reproduce them. Makes me upset if useful stuff is not attached .

Comment by Zeb [ 19/Jun/16 ]

@Mega_Spud: As stated in earlier comments, I don't think changing the type of mob spawner should work with observers because it is an NBT change which doesn't cause a block update.

Comment by [Mojang] Mega_Spud (Jay Wells) [ 19/Jun/16 ]

Taken from MCPE-15593:

No output when:
Changing what mobs spawn in spawner
Top door half
Activate fencegate via redstone
Activate rail with redstone
Toggling redstone torch in any way
changing daylight detector to inverted and opposite
Both weighted pressure plates sometimes dont make it toggle when atvivate, but always on deactivate

Comment by Zeb [ 19/Jun/16 ]

Yeah, I think placing redstone dust should be detected. It do wonder, though, if most of these problems are with the observer, or i they're actually caused by the other blocks. Maybe redstone dust doesn't cause a block update when its placed, and perhaps the same thing for redstone ore glowing, cocoa beans growing, and other things like that. This could be technically a bug with lots of blocks, but not actually the observer itself... if anyone has the ability to read the MCPE code, it would be interesting to know how the observer block detects updates and how block updates are caused. That could help in diagnosing the cause of this bug.

Comment by Jeff Jewett [ 19/Jun/16 ]

Also placing redstone next to an observer does not activate it but changes in the redstone's state and breaking the redstone does activate it. Not sure if this is WAI. Seems to me like like placing redstone should count as a block update if breaking it does

Comment by ItsPlantseed [ 19/Jun/16 ]

Confirmed for 0.15.1 alpha build 1.
Edit: I found a list in Minecraft Wiki, maybe some of them need to receive a block update.

Comment by ItsPlantseed [ 15/Jun/16 ]

And also affected the activator rails when activated by redstone, lightening nether portal, and growing cocoa pods.

Comment by Zeb [ 13/Jun/16 ]

Confirmed for 0.15.0 official release on Windows 10 Edition.

Also, some additional notes:
1. Redstone torches changing state don't affect the Observer at all. It's not just burned-out torches, it's any redstone torch changing state. Could it be possible that redstone torches do not use blockstates like the Java edition, and instead only use block entities? It may be works-as-intended for redstone torches. It could also be that redstone torches don't cause block updates at all when changing states, which could be the cause of several other redstone-related bugs as well...
2. Fence gates do not make any sound when powered by redstone... possibly related to the problem?

Comment by gatharian [ 07/Jun/16 ]

Confirmed for Samsung Galaxy Tab 4. 0.15.0 build 1

Comment by Charlotte Buff [ 05/Jun/16 ]

Paintings and mob spawners are most likely intended to not work since paintings aren't blocks and applying eggs to spawners only changes the block entity and doesn't update the actual block.

Comment by ItsPlantseed [ 05/Jun/16 ]

Affected:

  1. Fence Gates activated by redstone.
  2. Change the daylight sensor.
  3. Placing painting.
    Edit: Thanks randomguy32, I thought the painting was different from PC. (Like Item Frames)
  4. Burned redstone torch.
  5. Place mob eggs inside mob spawner.
  6. Reducing snowlayers height when shoot some arrows.
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