Fix intermittent UT failure re: recreating namespace

...due to a timing issue with updates with the fake client when the
cache isn't fully synced initially.

Signed-off-by: Tom Pantelis <tompantelis@gmail.com>

pkg/syncer/resource_syncer.go

@@ -194,7 +194,7 @@ type ResourceSyncerConfig struct {
 
 type resourceSyncer struct {
 	workQueue         workqueue.Interface
-	hasSynced         func() bool
+	cachesSynced      []cache.InformerSynced
 	unregHandler      func()
 	informer          cache.Controller
 	store             cache.Store
@@ -243,7 +243,7 @@ func NewResourceSyncer(config *ResourceSyncerConfig) (Interface, error) {
 		Transform: resourceUtil.TrimManagedFields,
 	})
 
-	syncer.hasSynced = syncer.informer.HasSynced
+	syncer.cachesSynced = append(syncer.cachesSynced, syncer.informer.HasSynced)
 
 	return syncer, nil
 }
@@ -265,7 +265,7 @@ func NewResourceSyncerWithSharedInformer(config *ResourceSyncerConfig, informer
 		return nil, errors.Wrapf(err, "error registering event handler")
 	}
 
-	syncer.hasSynced = reg.HasSynced
+	syncer.cachesSynced = append(syncer.cachesSynced, reg.HasSynced)
 
 	syncer.unregHandler = func() {
 		_ = informer.RemoveEventHandler(reg)
@@ -315,7 +315,7 @@ func newResourceSyncer(config *ResourceSyncerConfig) (*resourceSyncer, error) {
 	syncer.workQueue = workqueue.New(config.Name)
 
 	if config.NamespaceInformer != nil {
-		_, err := config.NamespaceInformer.AddEventHandler(cache.ResourceEventHandlerDetailedFuncs{
+		reg, err := config.NamespaceInformer.AddEventHandler(cache.ResourceEventHandlerDetailedFuncs{
 			AddFunc: func(obj interface{}, _ bool) {
 				syncer.workQueue.Enqueue(cache.ExplicitKey(cache.NewObjectName(namespaceAddedKey, resourceUtil.MustToMeta(obj).GetName()).String()))
 			},
@@ -329,6 +329,8 @@ func newResourceSyncer(config *ResourceSyncerConfig) (*resourceSyncer, error) {
 		if err != nil {
 			return nil, errors.Wrapf(err, "error registering namespace handler")
 		}
+
+		syncer.cachesSynced = append(syncer.cachesSynced, reg.HasSynced)
 	}
 
 	return syncer, nil
@@ -387,7 +389,7 @@ func (r *resourceSyncer) Start(stopCh <-chan struct{}) error {
 	if *r.config.WaitForCacheSync {
 		r.log.V(log.LIBDEBUG).Infof("Syncer %q waiting for informer cache to sync", r.config.Name)
 
-		_ = cache.WaitForCacheSync(stopCh, r.hasSynced)
+		_ = cache.WaitForCacheSync(stopCh, r.cachesSynced...)
 	}
 
 	r.workQueue.Run(stopCh, r.processNextWorkItem)
@@ -516,7 +518,7 @@ func (r *resourceSyncer) doReconcile(resourceLister func() []runtime.Object) {
 }
 
 func (r *resourceSyncer) runIfCacheSynced(defaultReturn any, run func() any) any {
-	if ok := cache.WaitForCacheSync(r.stopCh, r.hasSynced); !ok {
+	if ok := cache.WaitForCacheSync(r.stopCh, r.cachesSynced...); !ok {
 		// This means the cache was stopped.
 		r.log.Warningf("Syncer %q failed to wait for informer cache to sync", r.config.Name)
 
@@ -837,8 +839,6 @@ func (r *resourceSyncer) handleNamespaceAdded(namespace string) {
 			ns, name, _ := cache.SplitMetaNamespaceKey(k)
 			r.RequeueResource(name, ns)
 		}
-
-		delete(r.missingNamespaces, namespace)
 	}
 }
 

pkg/syncer/resource_syncer_test.go

@@ -1283,10 +1283,6 @@ func testWithMissingNamespace() {
 		createNamespace(test.LocalNamespace)
 
 		fakereactor.AddVerifyNamespaceReactor(&d.config.SourceClient.(*fakeClient.FakeDynamicClient).Fake, "pods")
-
-		if d.config.NamespaceInformer != nil {
-			go d.config.NamespaceInformer.Run(d.stopCh)
-		}
 	})
 
 	Specify("distribute should eventually succeed when the namespace is created", func() {
@@ -1500,6 +1496,12 @@ func newTestDriver(sourceNamespace, localClusterID string, syncDirection syncer.
 
 		Expect(err).To(Succeed())
 
+		if d.config.NamespaceInformer != nil {
+			go func() {
+				d.config.NamespaceInformer.Run(d.stopCh)
+			}()
+		}
+
 		utilruntime.ErrorHandlers = append(utilruntime.ErrorHandlers,
 			func(_ context.Context, err error, _ string, _ ...interface{}) {
 				d.handledError <- err