terraform: MergeDiff uses a Diff as an argument

terraform/state.go

@@ -110,8 +110,7 @@ type ResourceState struct {
 // If the diff attribute requires computing the value, and hence
 // won't be available until apply, the value is replaced with the
 // computeID.
-func (s *ResourceState) MergeDiff(
-	d map[string]*ResourceAttrDiff) *ResourceState {
+func (s *ResourceState) MergeDiff(d *ResourceDiff) *ResourceState {
 	var result ResourceState
 	if s != nil {
 		result = *s
@@ -123,7 +122,7 @@ func (s *ResourceState) MergeDiff(
 			result.Attributes[k] = v
 		}
 	}
-	for k, diff := range d {
+	for k, diff := range d.Attributes {
 		if diff.NewComputed {
 			result.Attributes[k] = config.UnknownVariableValue
 			continue

terraform/state_test.go

@@ -16,19 +16,21 @@ func TestResourceState_MergeDiff(t *testing.T) {
 		},
 	}
 
-	diff := map[string]*ResourceAttrDiff{
-		"foo": &ResourceAttrDiff{
-			Old: "bar",
-			New: "baz",
-		},
-		"bar": &ResourceAttrDiff{
-			Old: "",
-			New: "foo",
-		},
-		"baz": &ResourceAttrDiff{
-			Old:         "",
-			New:         "foo",
-			NewComputed: true,
+	diff := &ResourceDiff{
+		Attributes: map[string]*ResourceAttrDiff{
+			"foo": &ResourceAttrDiff{
+				Old: "bar",
+				New: "baz",
+			},
+			"bar": &ResourceAttrDiff{
+				Old: "",
+				New: "foo",
+			},
+			"baz": &ResourceAttrDiff{
+				Old:         "",
+				New:         "foo",
+				NewComputed: true,
+			},
 		},
 	}
 
@@ -48,10 +50,12 @@ func TestResourceState_MergeDiff(t *testing.T) {
 func TestResourceState_MergeDiff_nil(t *testing.T) {
 	var rs *ResourceState = nil
 
-	diff := map[string]*ResourceAttrDiff{
-		"foo": &ResourceAttrDiff{
-			Old: "",
-			New: "baz",
+	diff := &ResourceDiff{
+		Attributes: map[string]*ResourceAttrDiff{
+			"foo": &ResourceAttrDiff{
+				Old: "",
+				New: "baz",
+			},
 		},
 	}
 

terraform/terraform.go

@@ -190,7 +190,7 @@ func (t *Terraform) diffWalkFn(
 
 		// Determine the new state and update variables
 		vars := make(map[string]string)
-		rs := r.State.MergeDiff(diff.Attributes)
+		rs := r.State.MergeDiff(diff)
 		for ak, av := range rs.Attributes {
 			vars[fmt.Sprintf("%s.%s", r.Id, ak)] = av
 		}