terraform: modify Same to return true if list is computed

terraform/diff.go

@@ -358,19 +358,55 @@ func (d *InstanceDiff) Same(d2 *InstanceDiff) bool {
 	if d.RequiresNew() != d2.RequiresNew() {
 		return false
 	}
-	if len(d.Attributes) != len(d2.Attributes) {
+
+	// Go through the old diff and make sure the new diff has all the
+	// same attributes. To start, build up the check map to be all the keys.
+	checkOld := make(map[string]struct{})
+	checkNew := make(map[string]struct{})
+	for k, _ := range d.Attributes {
+		checkOld[k] = struct{}{}
+	}
+	for k, _ := range d2.Attributes {
+		checkNew[k] = struct{}{}
+	}
+	for k, diffOld := range d.Attributes {
+		if _, ok := checkOld[k]; !ok {
+			// We're not checking this key for whatever reason (see where
+			// check is modified).
+			continue
+		}
+
+		// Remove this key since we'll never hit it again
+		delete(checkOld, k)
+		delete(checkNew, k)
+
+		_, ok := d2.Attributes[k]
+		if !ok {
+			// The matching attribute was not found, we're different
 			return false
 		}
 
-	ks := make(map[string]struct{})
-	for k, _ := range d.Attributes {
-		ks[k] = struct{}{}
+		if diffOld.NewComputed && strings.HasSuffix(k, ".#") {
+			// This is a computed list, so remove any keys with this
+			// prefix from the check list.
+			kprefix := k[0:len(k)-2] + "."
+			for k2, _ := range checkOld {
+				if strings.HasPrefix(k2, kprefix) {
+					delete(checkOld, k2)
+				}
+			}
+			for k2, _ := range checkNew {
+				if strings.HasPrefix(k2, kprefix) {
+					delete(checkNew, k2)
+				}
 			}
-	for k, _ := range d2.Attributes {
-		delete(ks, k)
 		}
 
-	if len(ks) > 0 {
+		// TODO: check for the same value if not computed
+	}
+
+	// Check for leftover attributes
+	if len(checkNew) > 0 {
 		return false
 	}
 

terraform/diff_test.go

@@ -351,6 +351,22 @@ func TestInstanceDiffSame(t *testing.T) {
 			false,
 		},
 
+		// Extra attributes
+		{
+			&InstanceDiff{
+				Attributes: map[string]*ResourceAttrDiff{
+					"foo": &ResourceAttrDiff{},
+				},
+			},
+			&InstanceDiff{
+				Attributes: map[string]*ResourceAttrDiff{
+					"foo": &ResourceAttrDiff{},
+					"bar": &ResourceAttrDiff{},
+				},
+			},
+			false,
+		},
+
 		{
 			&InstanceDiff{
 				Attributes: map[string]*ResourceAttrDiff{
@@ -364,12 +380,33 @@ func TestInstanceDiffSame(t *testing.T) {
 			},
 			false,
 		},
+
+		{
+			&InstanceDiff{
+				Attributes: map[string]*ResourceAttrDiff{
+					"foo.#": &ResourceAttrDiff{NewComputed: true},
+				},
+			},
+			&InstanceDiff{
+				Attributes: map[string]*ResourceAttrDiff{
+					"foo.#": &ResourceAttrDiff{
+						Old: "0",
+						New: "1",
+					},
+					"foo.0": &ResourceAttrDiff{
+						Old: "",
+						New: "12",
+					},
+				},
+			},
+			true,
+		},
 	}
 
 	for i, tc := range cases {
 		actual := tc.One.Same(tc.Two)
 		if actual != tc.Same {
-			t.Fatalf("Fail %d", i)
+			t.Fatalf("%d:\n\n%#v\n\n%#v", i, tc.One, tc.Two)
 		}
 	}
 }