diff --git a/terraform/transform_destroy_edge.go b/terraform/transform_destroy_edge.go index 7fb415bdf..be1540ffe 100644 --- a/terraform/transform_destroy_edge.go +++ b/terraform/transform_destroy_edge.go @@ -277,5 +277,47 @@ func (t *DestroyEdgeTransformer) Transform(g *Graph) error { } } + return t.pruneResources(g) +} + +// If there are only destroy instances for a particular resource, there's no +// reason for the resource node to prepare the state. Remove Resource nodes so +// that they don't fail by trying to evaluate a resource that is only being +// destroyed along with its dependencies. +func (t *DestroyEdgeTransformer) pruneResources(g *Graph) error { + for _, v := range g.Vertices() { + n, ok := v.(*NodeApplyableResource) + if !ok { + continue + } + + // if there are only destroy dependencies, we don't need this node + des, err := g.Descendents(n) + if err != nil { + return err + } + + descendents := des.List() + nonDestroyInstanceFound := false + for _, v := range descendents { + if _, ok := v.(*NodeApplyableResourceInstance); ok { + nonDestroyInstanceFound = true + break + } + } + + if nonDestroyInstanceFound { + continue + } + + // connect all the through-edges, then delete the node + for _, d := range g.DownEdges(n).List() { + for _, u := range g.UpEdges(n).List() { + g.Connect(dag.BasicEdge(u, d)) + } + } + log.Printf("DestroyEdgeTransformer: pruning unused resource node %s", dag.VertexName(n)) + g.Remove(n) + } return nil }