Redstone blocks emit power through blocks
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is duplicated by 5
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Comments 17
Note that the power is 'BUD'-ed, that is, blocks will not notice a change until a block update (since the source is not adjacent)
Can confirm for 15w46a.
Can confirm for 15w46a aswell.
Can confirm too, it break a lot of previously working systems haha

This is a bug that seriously needs to be fixed. It would likely break all sorts of redstone contraptions. Can confirm that it happens now and not in 1.8.8

Partly repeating my comment from MC-5951 in case 'closed' means no one looks there... :~)
From their beginning comparators have required strong side-powering to function. They pull signal from behind like repeaters, push it out the front like repeaters, and require strong powering from the sides to change operation, just like repeaters. So MC-5951 was never a bug to begin with, just someone who didn't understand proper redstone functionality. And that basic functionality of comparators was not changed by the fix to MC-5951.
From their beginning RedStone Blocks behaved exactly like any other 'strongly powered' block, except that they were inherently strongly powered, rather than requiring power pushed into them. They have never behaved like 'omnidirectional repeaters' which is how they behave now, pushing power into all the blocks around them. This change severely breaks almost all redstone contraptions that use redstone blocks and throws existing slimestone (including Missile Wars and perhaps most other Realms prefab worlds) out the window for no functional gain (unless you consider hundreds of new BUD possibilities a good thing) and serious functional loss (even if you consider the BUD possibilities a good thing.)
[15w46a]
Just in case weight of comments is meaningful, I am experiencing the same behavior. Redstone blocks are strongly powering blocks touching any of their sides. Noticed this when I placed a redstone torch on some stone brick with a redstone block sitting on top of it. The torch went out, and it even lights lamps and redstone lines touching adjacent blocks in contact with it, like in the screenshots. Like Joseph said above, this breaks a lot of things and doesn't add much, hope it gets fixed. 🙂
Per se the changed redstone block mechanics are quite interesting. If it wouldn't break everything built so far with redstone blocks, that would be great. I think a good solution would be adding a new redstone block, that can power blocks. This would keep existing contraptions intact and offers more options to work with.
Fixed for a future version per Searge:
I discussed MC-5951 with @jeb_ and we decided to change the behavior of the redstone block back to what it was and fix the bug differently.
This is probably due to the 'fix' for MC-5951
5951 should have been resolved WAI probably.