CRAFTBOOK-2756 - Reported by dddeeefff

When you raise a gate, you are normally able to the close the gate via a different sign on the other side of the gate. However, some situations would have two signs both able to operate the gate, nut neither sign is able to access the other to check whether the sign has available the proper blocks to fill the gate.

At least these two setups result in the issue:
http://picpaste.com/2013-10-01_21.41.07-VJP4KZe3.png
http://picpaste.com/2013-10-01_21.47.56-UfcuJvhI.png

In the second picture, the second sign is just visible behind the right pillar

(Issue only affects those with the block spawning prevention mode turned on in their config)

Steps to reproduce:
1 Create a gate like in picture 2 or picture 1.
2 Open the gate on one side.
3 Walk through the gate
4 Attempt to close the gate on the other side. You get several messages saying there are not enough blocks and finally, a "failed to find gate" message

Thanks, dddeeefff

Comment by wizjany

i believe it's because you have the blocks stored in the signs and raising the gate on one side stores the blocks on that side so the other side doesn't have enough blocks to close the gate.

Comment by dddeeefff

yes, only in some placements the signs interact as one would expect. For example, if signs are facing in opposite directions and placed on the same block. Signs are capable of looking at each other to get blocks, it's just that in the cases above, they don't do it well enough

Comment by me4502

That's because they have no idea where each other are. It would be awfully innefficient to search a circular area for the signs, as it'd need to be quite large to take ever sign chance.

Comment by dddeeefff

Could signs can be linked by namespace? Is the first/third line free on the signs for that?

Comment by me4502

All lines on signs are already used for gates.