Do not mutate Role.Options when RenderScripts is called

models/role.go

@@ -13,7 +13,7 @@ type Role struct {
 
 func (r *Role) RenderScripts(options map[string]string) (map[DeploymentStage]string, error) {
 	rendered := make(map[DeploymentStage]string)
-	mergedOptions := mergeOptions(r.Options, options)
+	mergedOptions := mergeOptions(copyOptions(r.Options), options)
 
 	for stage, scriptTemplate := range r.ScriptTemplates {
 		var b bytes.Buffer
@@ -40,3 +40,11 @@ func mergeOptions(o1 map[string]string, o2 map[string]string) map[string]string
 	}
 	return o1
 }
+
+func copyOptions(options map[string]string) map[string]string {
+	result := make(map[string]string)
+	for key, value := range options {
+		result[key] = value
+	}
+	return result
+}

models/role_test.go

@@ -64,5 +64,11 @@ func TestRender(t *testing.T) {
 				t.Errorf("Rendering wrong. expected='%s', got='%s'", expectedScript, result[stage])
 			}
 		}
+
+		for name, _ := range otherOptions {
+			if role.Options[name] != "" {
+				t.Errorf("role.Options[%s] to be nil, got=%s", name, role.Options[name])
+			}
+		}
 	}
 }