From a104ecb69d284f2bfa55edd66d270bc499f71c1d Mon Sep 17 00:00:00 2001
From: James Bardin <j.bardin@gmail.com>
Date: Fri, 6 Mar 2020 16:34:18 -0500
Subject: [PATCH] GraphNodeExpand is not used

---
 terraform/graph.go                 | 13 -----
 terraform/transform_expand.go      | 39 ---------------
 terraform/transform_expand_test.go | 77 ------------------------------
 3 files changed, 129 deletions(-)
 delete mode 100644 terraform/transform_expand_test.go

diff --git a/terraform/graph.go b/terraform/graph.go
index 11cec4974..373819f7e 100644
--- a/terraform/graph.go
+++ b/terraform/graph.go
@@ -101,19 +101,6 @@ func (g *Graph) walk(walker GraphWalker) tfdiags.Diagnostics {
 				log.Printf("[TRACE] vertex %q: produced no dynamic subgraph", dag.VertexName(v))
 			}
 		}
-
-		// If the node has a subgraph, then walk the subgraph
-		if sn, ok := v.(GraphNodeSubgraph); ok {
-			log.Printf("[TRACE] vertex %q: entering static subgraph", dag.VertexName(v))
-
-			subDiags := sn.Subgraph().(*Graph).walk(walker)
-			if subDiags.HasErrors() {
-				log.Printf("[TRACE] vertex %q: static subgraph encountered errors", dag.VertexName(v))
-				return
-			}
-			log.Printf("[TRACE] vertex %q: static subgraph completed successfully", dag.VertexName(v))
-		}
-
 		return
 	}
 
diff --git a/terraform/transform_expand.go b/terraform/transform_expand.go
index 982c098b8..dca71b630 100644
--- a/terraform/transform_expand.go
+++ b/terraform/transform_expand.go
@@ -1,18 +1,5 @@
 package terraform
 
-import (
-	"log"
-
-	"github.com/hashicorp/terraform/dag"
-)
-
-// GraphNodeExapndable is an interface that nodes can implement to
-// signal that they can be expanded. Expanded nodes turn into
-// GraphNodeSubgraph nodes within the graph.
-type GraphNodeExpandable interface {
-	Expand(GraphBuilder) (GraphNodeSubgraph, error)
-}
-
 // GraphNodeDynamicExpandable is an interface that nodes can implement
 // to signal that they can be expanded at eval-time (hence dynamic).
 // These nodes are given the eval context and are expected to return
@@ -20,29 +7,3 @@ type GraphNodeExpandable interface {
 type GraphNodeDynamicExpandable interface {
 	DynamicExpand(EvalContext) (*Graph, error)
 }
-
-// GraphNodeSubgraph is an interface a node can implement if it has
-// a larger subgraph that should be walked.
-type GraphNodeSubgraph interface {
-	Subgraph() dag.Grapher
-}
-
-// ExpandTransform is a transformer that does a subgraph expansion
-// at graph transform time (vs. at eval time). The benefit of earlier
-// subgraph expansion is that errors with the graph build can be detected
-// at an earlier stage.
-type ExpandTransform struct {
-	Builder GraphBuilder
-}
-
-func (t *ExpandTransform) Transform(v dag.Vertex) (dag.Vertex, error) {
-	ev, ok := v.(GraphNodeExpandable)
-	if !ok {
-		// This isn't an expandable vertex, so just ignore it.
-		return v, nil
-	}
-
-	// Expand the subgraph!
-	log.Printf("[DEBUG] vertex %q: static expanding", dag.VertexName(ev))
-	return ev.Expand(t.Builder)
-}
diff --git a/terraform/transform_expand_test.go b/terraform/transform_expand_test.go
deleted file mode 100644
index d422eddf0..000000000
--- a/terraform/transform_expand_test.go
+++ /dev/null
@@ -1,77 +0,0 @@
-package terraform
-
-import (
-	"strings"
-	"testing"
-
-	"github.com/hashicorp/terraform/dag"
-)
-
-func TestExpandTransform_impl(t *testing.T) {
-	var _ GraphVertexTransformer = new(ExpandTransform)
-}
-
-func TestExpandTransform(t *testing.T) {
-	var g Graph
-	g.Add(1)
-	g.Add(2)
-	g.Connect(dag.BasicEdge(1, 2))
-
-	tf := &ExpandTransform{}
-	out, err := tf.Transform(&testExpandable{
-		Result: &g,
-	})
-	if err != nil {
-		t.Fatalf("err: %s", err)
-	}
-
-	sn, ok := out.(GraphNodeSubgraph)
-	if !ok {
-		t.Fatalf("not subgraph: %#v", out)
-	}
-
-	actual := strings.TrimSpace(sn.Subgraph().(*Graph).String())
-	expected := strings.TrimSpace(testExpandTransformStr)
-	if actual != expected {
-		t.Fatalf("bad: %s", actual)
-	}
-}
-
-func TestExpandTransform_nonExpandable(t *testing.T) {
-	tf := &ExpandTransform{}
-	out, err := tf.Transform(42)
-	if err != nil {
-		t.Fatalf("err: %s", err)
-	}
-	if out != 42 {
-		t.Fatalf("bad: %#v", out)
-	}
-}
-
-type testExpandable struct {
-	// Inputs
-	Result      *Graph
-	ResultError error
-
-	// Outputs
-	Builder GraphBuilder
-}
-
-func (n *testExpandable) Expand(b GraphBuilder) (GraphNodeSubgraph, error) {
-	n.Builder = b
-	return &testSubgraph{n.Result}, n.ResultError
-}
-
-type testSubgraph struct {
-	Graph *Graph
-}
-
-func (n *testSubgraph) Subgraph() dag.Grapher {
-	return n.Graph
-}
-
-const testExpandTransformStr = `
-1
-  2
-2
-`