I had been using Link Call nodes for a few months, but the other day I found they had stopped working. I looked into it and the debug window says "Missing return node information", but I haven't changed the flow itself. They are set to Return To Calling Node.
I tried changing it to "Send To All Connected Nodes", but the Link Call node isn't shown. (Well, it has the same name as the Link Out node, but that's always been like that.) When I select that one, it just creates a loop. (the wires, not a programming loop)
The error means the message that reaches the Link Out node at the end of the call is missing the property that tells the node where to return the message to.
Specifically, it needs to have the msg._linkSource property.
Add a debug node at different points of your called flow to see where that property is being lost.
Surprise, surprise, it was user error.
I had added an inject node inside the called flow and obviously it wasn't transmitting any msg._linkSource property. I thought about adding it to the inject node, but I figure that the unique ID could change which would break it. Easier to just add a long wire.
Thanks for exaplaining how that works, Nick, that helps a lot.
