state: LocalState allows file to not exist

state/local.go

@@ -44,6 +44,12 @@ func (s *LocalState) PersistState() error {
 func (s *LocalState) RefreshState() error {
 	f, err := os.Open(s.Path)
 	if err != nil {
+		// It is okay if the file doesn't exist, we treat that as a nil state
+		if os.IsNotExist(err) {
+			s.state = nil
+			return nil
+		}
+
 		return err
 	}
 	defer f.Close()

state/local_test.go

@@ -14,6 +14,17 @@ func TestLocalState(t *testing.T) {
 	TestState(t, ls)
 }
 
+func TestLocalState_nonExist(t *testing.T) {
+	ls := &LocalState{Path: "ishouldntexist"}
+	if err := ls.RefreshState(); err != nil {
+		t.Fatalf("err: %s", err)
+	}
+
+	if state := ls.State(); state != nil {
+		t.Fatalf("bad: %#v", state)
+	}
+}
+
 func TestLocalState_impl(t *testing.T) {
 	var _ StateReader = new(LocalState)
 	var _ StateWriter = new(LocalState)