fix the bug for setting annotations when triggering transformers

pkg/plugins/execplugin.go

@@ -208,12 +208,10 @@ func (p *ExecPlugin) getResMapWithIdAnnotation(rm resmap.ResMap) (resmap.ResMap,
 		}
 		annotations := r.GetAnnotations()
 		if annotations == nil {
-			annotations = map[string]string{
+			annotations = make(map[string]string)
-				idAnnotation: string(idString),
-			}
-			r.SetAnnotations(annotations)
 		}
 		annotations[idAnnotation] = string(idString)
+		r.SetAnnotations(annotations)
 	}
 	return inputRM, nil
 }

pkg/target/transformerplugin_test.go

@@ -113,6 +113,9 @@ func TestSedTransformer(t *testing.T) {
 	th := kusttest_test.NewKustTestHarnessWithPluginConfig(
 		t, "/app", plugin.ActivePluginConfig())
 	th.WriteK("/app", `
+resources:
+- configmap.yaml
+
 transformers:
 - sed-transformer.yaml
 
@@ -134,12 +137,32 @@ s/$FOO/foo/g
 s/$BAR/bar/g
 `)
 
+	th.WriteF("/app/configmap.yaml", `
+apiVersion: v1
+kind: ConfigMap
+metadata:
+  name: configmap-a
+  annotations:
+    kustomize.k8s.io/Generated: "false"
+data:
+  foo: $FOO
+`)
+
 	m, err := th.MakeKustTarget().MakeCustomizedResMap()
 	if err != nil {
 		t.Fatalf("Err: %v", err)
 	}
 	th.AssertActualEqualsExpected(m, `
 apiVersion: v1
+data:
+  foo: foo
+kind: ConfigMap
+metadata:
+  annotations:
+    kustomize.k8s.io/Generated: "false"
+  name: configmap-a
+---
+apiVersion: v1
 data:
   BAR: bar
   FOO: foo