helper/schema: test schema diffs with the interpolation splits

builtin/providers/aws/structure.go

@@ -188,14 +188,6 @@ func flattenInstances(list []elb.Instance) []string {
 // Takes the result of flatmap.Expand for an array of strings
 // and returns a []string
 func expandStringList(configured []interface{}) []string {
-	// here we special case the * expanded lists. For example:
-	//
-	//	 instances = ["${aws_instance.foo.*.id}"]
-	//
-	if len(configured) == 1 && strings.Contains(configured[0].(string), ",") {
-		return strings.Split(configured[0].(string), ",")
-	}
-
 	vs := make([]string, 0, len(configured))
 	for _, v := range configured {
 		vs = append(vs, v.(string))

helper/schema/schema_test.go

@@ -385,6 +385,49 @@ func TestSchemaMap_Diff(t *testing.T) {
 			Err: false,
 		},
 
+		{
+			Schema: map[string]*Schema{
+				"ports": &Schema{
+					Type:     TypeList,
+					Required: true,
+					Elem:     &Schema{Type: TypeInt},
+				},
+			},
+
+			State: nil,
+
+			Config: map[string]interface{}{
+				"ports": []interface{}{1, "${var.foo}"},
+			},
+
+			ConfigVariables: map[string]string{
+				"var.foo": "2" + config.InterpSplitDelim + "5",
+			},
+
+			Diff: &terraform.InstanceDiff{
+				Attributes: map[string]*terraform.ResourceAttrDiff{
+					"ports.#": &terraform.ResourceAttrDiff{
+						Old: "0",
+						New: "3",
+					},
+					"ports.0": &terraform.ResourceAttrDiff{
+						Old: "",
+						New: "1",
+					},
+					"ports.1": &terraform.ResourceAttrDiff{
+						Old: "",
+						New: "2",
+					},
+					"ports.2": &terraform.ResourceAttrDiff{
+						Old: "",
+						New: "5",
+					},
+				},
+			},
+
+			Err: false,
+		},
+
 		{
 			Schema: map[string]*Schema{
 				"ports": &Schema{