Redstone Block + Sticky Piston / once activated piston won't deactivate

Confirmed in 1.5.1 on Linux. Affects only the posted construction. Sideways pistons work as expected. See http://www.youtube.com/watch?v=a9hhCaFmWCE

$ uname -rms
Linux 3.8.4-1-ARCH x86_64

$ java -version
java version "1.7.0_17"
OpenJDK Runtime Environment (IcedTea7 2.3.8) (ArchLinux build 7.u17_2.3.8-1-x86_64)
OpenJDK 64-Bit Server VM (build 23.7-b01, mixed mode)

138th duplicate of MC-108, please use the search function to see if your bug has already been submitted. Currently over 54% of tickets are being closed as duplicate.

MC-108 says “… when blocks are providing power diagonally or two blocks above”. In this bug here it’s neither diagonally nor two blocks above, it’s vertically and one block above.

2 Redstone block
1 Piston pusher
0 Piston base

Sorry Kumasasa, I did a search and from the results I got that sounded like an issue that hasn't been described in any of the other cases. I still think it was worth a report; as the one you mention doesn't particular describe the setup I used - or I just don't understand it. One more reason not to assume I didn't use the search.

As I am not a developer I am however unaware if the block setup I used has the same problem underlying as all the others reported. Therefore I created this new case instead of 'assuming' my issue would be covered by any of the other reports with a different setup. I also had the Redstone Block as a source and none of the other powering options. Maybe I used the wrong keywords then?

Btw. automatically assuming that someone who reports a duplicate didn't use the search from your point of view is actually quite rude. There are so many factors that play into creating a duplicate that do not necessarily have to be connected to not using the search (i.e. not understanding the underlying problem, not having found the problem, not used the right key words, overseen the original bug report by scanning through so many others - it's not like there is only THE OBVIOUS bug report that is easy to see/relate to and therefore makes you discard your own).

Thank you.

I clearly see your points but I didn't want to sound rude - you've simply got the "default-duplicate-resolved-template".
Please do not expect to get a personal letter when resolving a duplicate, we've got > 6700 duplicates here.

According to dinnerbone (https://twitter.com/Dinnerbone/status/313237462757543937), this is not (as you have specifically described it here) a bug as it is a consequence of intended behaviour, although I do admit that it does seem counter-intuitive. Please allow me to explain:

It's first worth noting that this applies to all pistons, not just sticky pistons. This is also not a duplicate of MC-108 in the precise sense, but rather an inverse of it, for the leftmost pistons are actually showing the intended states of the pistons in this set up - placing/updating adjacent blocks around the piston changes nothing. However, if you place a piston in any orientation on the ground and then immediately place a redstone block two blocks above it, then the pistons require an update of the adjacent blocks to extend. For all practical purposes however, I feel it is understandable label it as a duplicate.

The reason as to why (according to dinnerbone) this specific issue is not a bug as you have described it is as follows: it has always been the case that a piston would accept a signal from two blocks above it (regardless of orientation). Since the redstone block in your first two pistons is two blocks above the piston and since redstone blocks send signals downwards (placing redstone dust immediately below a redstone block will power the dust), the block is powering the piston and thus it remains extended. A rather unusual consequence of this behaviour is that if you have a piston in any other orientation (e.g. to the side) and you have a redstone block two blocks above it, then the piston should extend even though there is a block of air permanently separating the two. Personally, I feel this is a bit silly and shouldn't be considered normal behaviour, but then again, I'm not a developer.

As for the rightmost piston in the picture, I can only offer conjecture as to why it does not extend and why this too is most likely intended behaviour. When dealing with pistons in a horizontal layout - i.e. solely within 1 block of height - powering a piston with redstone dust from the block immediately in front of the pushing arm will not power the piston. The reason for this is most likely to prevent the piston from destroying it's own power source. Attempting to recreate this scenario in a vertical layout however, does cause the piston to extend (even if you avoid powering it diagonally). Whether this in itself could be considered a bug is a matter for debate. My guess is that with the addition of redstone blocks, this behaviour of not powering the piston immediately in front of the pushing arm was extended to the redstone blocks, including in the vertical orientation, thus explaining the third piston in your picture.

I hope this helps.