lib/model, lib/util: Replace IsComplete with NoRestartErr (ref #6947) (#7126)

lib/util/utils.go

@@ -246,6 +246,31 @@ func (e *FatalErr) Is(target error) bool {
 	return target == suture.ErrTerminateSupervisorTree
 }
 
+// NoRestartErr wraps the given error err (which may be nil) to make sure that
+// `errors.Is(err, suture.ErrDoNotRestart) == true`.
+func NoRestartErr(err error) error {
+	if err == nil {
+		return suture.ErrDoNotRestart
+	}
+	return &noRestartErr{err}
+}
+
+type noRestartErr struct {
+	err error
+}
+
+func (e *noRestartErr) Error() string {
+	return e.err.Error()
+}
+
+func (e *noRestartErr) Unwrap() error {
+	return e.err
+}
+
+func (e *noRestartErr) Is(target error) bool {
+	return target == suture.ErrDoNotRestart
+}
+
 type ExitStatus int
 
 const (