Composition freezes with certain structure of triggers + feedback loops

Steps causing the bug to occur

@casdekker reported a problem with their composition:

In the subcomposition are two Smooth with Duration nodes which animate the start and end of a lineair gradient. A few seconds after starting the main composition the ‘Position’ of the Smooth with Duration nodes stops. (Again, it runs for the first couple of seconds) The ‘Time’ that is being put into the Smooth with Duration node is still running. The ‘Target’ is not reached and I tried it with both the ‘Time’ coming from within the subcomposition and from a published input port.

When running the subcomposition as a composition on its own, everything works fine.

We pared down the Smooth with Duration and surrounding nodes to a fairly simple composition that reproduces the problem:

In investigating the problem so far, it looks like Vuo is not correctly scheduling some nodes, resulting in a deadlock. Something about the structure of the two Fire Periodically nodes, Random Start/stop, and Smooth with Duration is throwing it off. (Yet slightly different feedback loops work.)

Since the problem happens in a top-level composition, it’s not directly caused by subcompositions, but could show up when refactoring composition parts into subcompositions if the subcompositions end up with different event flow than the original nodes.

Have you found a workaround?

Insert a Hold Value node:

Other notes

  • Vuo version: 1.2.5

TriphTest5.vuo (2.51 KB)

TriphTest5-workaround.vuo (2.55 KB)

Scheduled for work.

Fixed in Vuo 1.2.6.