helper/schema: test real nil pointer to ResourceData.Set

helper/schema/resource_data.go

@@ -143,11 +143,18 @@ func (d *ResourceData) Set(key string, value interface{}) error {
 	// simplify the interface.
 	reflectVal := reflect.ValueOf(value)
 	if reflectVal.Kind() == reflect.Ptr {
+		if reflectVal.IsNil() {
+			// If the pointer is nil, then the value is just nil
+			value = nil
+		} else {
+			// Otherwise, we dereference the pointer as long as its not
+			// a pointer to a struct, since struct pointers are allowed.
 			reflectVal = reflect.Indirect(reflectVal)
 			if reflectVal.Kind() != reflect.Struct {
 				value = reflectVal.Interface()
 			}
 		}
+	}
 
 	return d.setWriter.WriteField(strings.Split(key, "."), value)
 }

helper/schema/resource_data_test.go

@@ -1178,6 +1178,8 @@ func TestResourceDataHasChange(t *testing.T) {
 }
 
 func TestResourceDataSet(t *testing.T) {
+	var testNilPtr *string
+
 	cases := []struct {
 		Schema   map[string]*Schema
 		State    *terraform.InstanceState
@@ -1649,7 +1651,7 @@ func TestResourceDataSet(t *testing.T) {
 			Diff: nil,
 
 			Key:   "availability_zone",
-			Value: nil,
+			Value: testNilPtr,
 
 			GetKey:   "availability_zone",
 			GetValue: "",