terraform: missing provider should be flattenable

terraform/graph_config_node_module.go

@@ -220,16 +220,6 @@ type graphNodeModuleFlatWrap struct {
 	DependentOnPrefix string
 }
 
-// GraphNodeProvider impl.
-func (n *graphNodeModuleFlatWrap) ProviderName() string {
-	pn, ok := n.Vertex.(GraphNodeProvider)
-	if !ok {
-		return ""
-	}
-
-	return fmt.Sprintf("%s.%s", n.NamePrefix, pn.ProviderName())
-}
-
 // GraphNodeProviderConsumer impl.
 func (n *graphNodeModuleFlatWrap) ProvidedBy() []string {
 	pn, ok := n.Vertex.(GraphNodeProviderConsumer)

terraform/transform_provider.go

@@ -224,6 +224,14 @@ func (n *graphNodeMissingProvider) DotOrigin() bool {
 	return true
 }
 
+// GraphNodeFlattenable impl.
+func (n *graphNodeMissingProvider) Flatten(p []string) (dag.Vertex, error) {
+	return &graphNodeMissingProviderFlat{
+		graphNodeMissingProvider: n,
+		PathValue:                p,
+	}, nil
+}
+
 func providerVertexMap(g *Graph) map[string]dag.Vertex {
 	m := make(map[string]dag.Vertex)
 	for _, v := range g.Vertices() {
@@ -234,3 +242,25 @@ func providerVertexMap(g *Graph) map[string]dag.Vertex {
 
 	return m
 }
+
+// Same as graphNodeMissingProvider, but for flattening
+type graphNodeMissingProviderFlat struct {
+	*graphNodeMissingProvider
+
+	PathValue []string
+}
+
+func (n *graphNodeMissingProviderFlat) Name() string {
+	return fmt.Sprintf(
+		"%s.%s", modulePrefixStr(n.PathValue), n.graphNodeMissingProvider.Name())
+}
+
+func (n *graphNodeMissingProviderFlat) Path() []string {
+	return n.PathValue
+}
+
+func (n *graphNodeMissingProviderFlat) ProviderName() string {
+	return fmt.Sprintf(
+		"%s.%s", modulePrefixStr(n.PathValue),
+		n.graphNodeMissingProvider.ProviderName())
+}