I'm finding a weird difference in behavior between 1.8 and 1.7.10 that maybe someone can explain.

 

I have a schematic (basically my own which is just text file with lots blocks, metadata and position) that I read and place. This has worked well for me for a long time and previous versions.

 

In one schematic I have a trap with arrow dispenser with trip wire hook and trip wire to make an arrow trap.

 

Because trip wire kinda self-configures based on what is around it, I place it last in my structure generation, after all other blocks are placed.

 

It works great in 1.7.10. Walk back and forth across the trip wire and it will keep shooting arrows each time until the dispenser runs out.

 

However, in 1.8 walking across the trip wire will not fire an arrow. However if I press F3 and hover over the string, trip wire hook and the dispenser, they all show that they are actively set as a trap. Even weirder though is that if I break the trip wire and place new string, it will shoot once even if I'm not on the trip wire and will not fire again unless I break the trip wire and place new string again.

 

Anyone have any ideas on why this is happening? I'm not aware of any mode where simply placing the trip wire without standing on it would trigger the dispenser, and I'm not aware of why it would say that the trap is set but won't activate when walking across it.

As mentioned, using F3 ingame you can inspect the state of the tripwire, the hook and the dispenser. The dispenser is "triggered", the hooks are "attached" as are all the parts to the trip wire itself.

 

However, interestingly if I placed the blocks using the metadata in my schematic, every other piece of trip wire would either show "powered" or not powered. If I place the blocks using default state (this is 1.8 ) then they all show "powered" but the behavior is the same.

 

If I break all the wire and place new wire down, the trap works perfectly fine.

 

Anyway, there is still something strange about it in 1.8. The circuit is sort of supposed to be self-correcting as far as I know -- I mean each piece detects whether it's attached, triggered, etc. And the setBlock function calls onBlockAdded() method for the trip wire which does a notifyTriggers() call.

 

Still looking for ideas...

I got it working by spreading the generation out over several ticks, although the code was pretty much identical.

 

I think the problem must have been that maybe the networking got jammed up with so many blocks created so quickly that it had trouble. Allowing it some time by breaking up the work over multiple ticks maybe allowed it to catch up.

 

Anyway, I got it working, but just wish I could confirm why it didn't work.