Also, I think it might be better to take the opportunity to rewrite the function to not use recursion. I don't quite see the need for it here and it looks like that might have helped contribute to the reported issue. Can't we just write this as a while loop instead of having the function call itself? It's not as if we need stack space for keeping track of multiple parents. A child relation can only have 1 parent. It seems to me that we can just walk there by looping.
My best guess is that this function is intended to share the same code pattern as in adjust_appendrel_attrs_multilevel. The recursion is needed as 'rel' can be more than one inheritance level below the top parent. I think we can keep the recursion, as in other similar functions, as long as we make it right, as in attached patch.
