For example, say I have this loop:



Since weightsdoesn't change during the loop, I thought I can directly connect it like this.

However, it seems to be causing a very obscure bug. Passing it to __spare__fixes them:



It's quite hard to explain what kind of bug I've run into, since it only happens in a rather complicated rig of mine. The only thing I know is that passing an array that doesn't change during the loop to __spare__fixed it.

Is there an official explanation of this __spare__thing and what should be connected to it?

In the next major release, we're going to be stricter with this. Passing anything you use inside a loop through the "spare" is the right thing to do as it allows better topological sorting of the graph for evaluation. This includes nodes inside If blocks as well.