Add cross-version compatibility with client-go 1.27

Author: howardjohn

pkg/cache/multi_namespace_cache.go

@@ -305,42 +305,63 @@ type multiNamespaceInformer struct {
 	namespaceToInformer map[string]Informer
 }
 
+type handlerRegistration struct {
+	handles map[string]toolscache.ResourceEventHandlerRegistration
+}
+
+type syncer interface {
+	HasSynced() bool
+}
+
+// HasSynced asserts that the handler has been called for the full initial state of the informer.
+// This uses syncer to be compatible between client-go 1.27+ and older versions when the interface changed.
+func (h handlerRegistration) HasSynced() bool {
+	for _, reg := range h.handles {
+		if s, ok := reg.(syncer); ok {
+			if !s.HasSynced() {
+				return false
+			}
+		}
+	}
+	return true
+}
+
 var _ Informer = &multiNamespaceInformer{}
 
 // AddEventHandler adds the handler to each namespaced informer.
 func (i *multiNamespaceInformer) AddEventHandler(handler toolscache.ResourceEventHandler) (toolscache.ResourceEventHandlerRegistration, error) {
-	handles := make(map[string]toolscache.ResourceEventHandlerRegistration, len(i.namespaceToInformer))
+	handles := handlerRegistration{handles: make(map[string]toolscache.ResourceEventHandlerRegistration, len(i.namespaceToInformer))}
 	for ns, informer := range i.namespaceToInformer {
 		registration, err := informer.AddEventHandler(handler)
 		if err != nil {
 			return nil, err
 		}
-		handles[ns] = registration
+		handles.handles[ns] = registration
 	}
 	return handles, nil
 }
 
 // AddEventHandlerWithResyncPeriod adds the handler with a resync period to each namespaced informer.
 func (i *multiNamespaceInformer) AddEventHandlerWithResyncPeriod(handler toolscache.ResourceEventHandler, resyncPeriod time.Duration) (toolscache.ResourceEventHandlerRegistration, error) {
-	handles := make(map[string]toolscache.ResourceEventHandlerRegistration, len(i.namespaceToInformer))
+	handles := handlerRegistration{handles: make(map[string]toolscache.ResourceEventHandlerRegistration, len(i.namespaceToInformer))}
 	for ns, informer := range i.namespaceToInformer {
 		registration, err := informer.AddEventHandlerWithResyncPeriod(handler, resyncPeriod)
 		if err != nil {
 			return nil, err
 		}
-		handles[ns] = registration
+		handles.handles[ns] = registration
 	}
 	return handles, nil
 }
 
 // RemoveEventHandler removes a formerly added event handler given by its registration handle.
 func (i *multiNamespaceInformer) RemoveEventHandler(h toolscache.ResourceEventHandlerRegistration) error {
-	handles, ok := h.(map[string]toolscache.ResourceEventHandlerRegistration)
+	handles, ok := h.(handlerRegistration)
 	if !ok {
 		return fmt.Errorf("it is not the registration returned by multiNamespaceInformer")
 	}
 	for ns, informer := range i.namespaceToInformer {
-		registration, ok := handles[ns]
+		registration, ok := handles.handles[ns]
 		if !ok {
 			continue
 		}

pkg/controller/controllertest/util.go

@@ -33,7 +33,49 @@ type FakeInformer struct {
 	// RunCount is incremented each time RunInformersAndControllers is called
 	RunCount int
 
-	handlers []cache.ResourceEventHandler
+	handlers []eventHandlerWrapper
+}
+
+type modernResourceEventHandler interface {
+	OnAdd(obj interface{}, isInInitialList bool)
+	OnUpdate(oldObj, newObj interface{})
+	OnDelete(obj interface{})
+}
+
+type legacyResourceEventHandler interface {
+	OnAdd(obj interface{})
+	OnUpdate(oldObj, newObj interface{})
+	OnDelete(obj interface{})
+}
+
+// eventHandlerWrapper wraps a ResourceEventHandler in a manner that is compatible with client-go 1.27+ and older.
+// The interface was changed in these versions.
+type eventHandlerWrapper struct {
+	handler any
+}
+
+func (e eventHandlerWrapper) OnAdd(obj interface{}) {
+	if m, ok := e.handler.(modernResourceEventHandler); ok {
+		m.OnAdd(obj, false)
+		return
+	}
+	e.handler.(legacyResourceEventHandler).OnAdd(obj)
+}
+
+func (e eventHandlerWrapper) OnUpdate(oldObj, newObj interface{}) {
+	if m, ok := e.handler.(modernResourceEventHandler); ok {
+		m.OnUpdate(oldObj, newObj)
+		return
+	}
+	e.handler.(legacyResourceEventHandler).OnUpdate(oldObj, newObj)
+}
+
+func (e eventHandlerWrapper) OnDelete(obj interface{}) {
+	if m, ok := e.handler.(modernResourceEventHandler); ok {
+		m.OnDelete(obj)
+		return
+	}
+	e.handler.(legacyResourceEventHandler).OnDelete(obj)
 }
 
 // AddIndexers does nothing.  TODO(community): Implement this.
@@ -58,7 +100,7 @@ func (f *FakeInformer) HasSynced() bool {
 
 // AddEventHandler implements the Informer interface.  Adds an EventHandler to the fake Informers. TODO(community): Implement Registration.
 func (f *FakeInformer) AddEventHandler(handler cache.ResourceEventHandler) (cache.ResourceEventHandlerRegistration, error) {
-	f.handlers = append(f.handlers, handler)
+	f.handlers = append(f.handlers, eventHandlerWrapper{handler})
 	return nil, nil
 }
 

pkg/internal/source/event_handler.go

@@ -32,8 +32,6 @@ import (
 
 var log = logf.RuntimeLog.WithName("source").WithName("EventHandler")
 
-var _ cache.ResourceEventHandler = &EventHandler{}
-
 // NewEventHandler creates a new EventHandler.
 func NewEventHandler(ctx context.Context, queue workqueue.RateLimitingInterface, handler handler.EventHandler, predicates []predicate.Predicate) *EventHandler {
 	return &EventHandler{
@@ -55,6 +53,15 @@ type EventHandler struct {
 	predicates []predicate.Predicate
 }
 
+// HandlerFuncs converts EventHandler to a ResourceEventHandlerFuncs
+func (e *EventHandler) HandlerFuncs() cache.ResourceEventHandlerFuncs {
+	return cache.ResourceEventHandlerFuncs{
+		AddFunc:    e.OnAdd,
+		UpdateFunc: e.OnUpdate,
+		DeleteFunc: e.OnDelete,
+	}
+}
+
 // OnAdd creates CreateEvent and calls Create on EventHandler.
 func (e *EventHandler) OnAdd(obj interface{}) {
 	c := event.CreateEvent{}

pkg/internal/source/kind.go

@@ -79,7 +79,7 @@ func (ks *Kind) Start(ctx context.Context, handler handler.EventHandler, queue w
 			return
 		}
 
-		_, err := i.AddEventHandler(NewEventHandler(ctx, queue, handler, prct))
+		_, err := i.AddEventHandler(NewEventHandler(ctx, queue, handler, prct).HandlerFuncs())
 		if err != nil {
 			ks.started <- err
 			return

pkg/source/source.go

@@ -204,7 +204,7 @@ func (is *Informer) Start(ctx context.Context, handler handler.EventHandler, que
 		return fmt.Errorf("must specify Informer.Informer")
 	}
 
-	_, err := is.Informer.AddEventHandler(internal.NewEventHandler(ctx, queue, handler, prct))
+	_, err := is.Informer.AddEventHandler(internal.NewEventHandler(ctx, queue, handler, prct).HandlerFuncs())
 	if err != nil {
 		return err
 	}