SQUASH: flatten DeepCopyFor types

Signed-off-by: Dr. Stefan Schimanski <stefan.schimanski@gmail.com>

pkg/builder/controller.go

@@ -288,8 +288,8 @@ func (blder *Builder) doWatch() error {
 			return err
 		}
 		src := clusterAwareSource{
-			Source:              source.Kind(blder.cluster.GetCache(), obj),
-			forceDefaultCluster: blder.forInput.forceDefaultCluster,
+			DeepCopyableSyncingSource: source.Kind(blder.cluster.GetCache(), obj),
+			forceDefaultCluster:       blder.forInput.forceDefaultCluster,
 		}
 		hdler := &handler.EnqueueRequestForObject{}
 		allPredicates := append([]predicate.Predicate(nil), blder.globalPredicates...)
@@ -309,8 +309,8 @@ func (blder *Builder) doWatch() error {
 			return err
 		}
 		src := clusterAwareSource{
-			Source:              source.Kind(blder.cluster.GetCache(), obj),
-			forceDefaultCluster: own.forceDefaultCluster,
+			DeepCopyableSyncingSource: source.Kind(blder.cluster.GetCache(), obj),
+			forceDefaultCluster:       own.forceDefaultCluster,
 		}
 		opts := []handler.OwnerOption{}
 		if !own.matchEveryOwner {
@@ -334,12 +334,17 @@ func (blder *Builder) doWatch() error {
 	}
 	for _, w := range blder.watchesInput {
 		// If the source of this watch is of type Kind, project it.
+		src := w.src
 		if srcKind, ok := w.src.(*internalsource.Kind); ok {
 			typeForSrc, err := blder.project(srcKind.Type, w.objectProjection)
 			if err != nil {
 				return err
 			}
 			srcKind.Type = typeForSrc
+			src = clusterAwareSource{
+				DeepCopyableSyncingSource: srcKind,
+				forceDefaultCluster:       w.forceDefaultCluster,
+			}
 		} else if !ok {
 			// If we're building a cluster-aware controller, raw watches are not allowed
 			// given that the cache cannot be validated to be coming from the same cluster.
@@ -351,10 +356,7 @@ func (blder *Builder) doWatch() error {
 		}
 		allPredicates := append([]predicate.Predicate(nil), blder.globalPredicates...)
 		allPredicates = append(allPredicates, w.predicates...)
-		if err := blder.ctrl.Watch(
-			clusterAwareSource{Source: w.src, forceDefaultCluster: w.forceDefaultCluster},
-			w.eventHandler, allPredicates...,
-		); err != nil {
+		if err := blder.ctrl.Watch(src, w.eventHandler, allPredicates...); err != nil {
 			return err
 		}
 	}
@@ -445,7 +447,7 @@ func (blder *Builder) doController(r reconcile.Reconciler) error {
 }
 
 type clusterAwareSource struct {
-	source.Source
+	source.DeepCopyableSyncingSource
 	forceDefaultCluster bool
 }
 

pkg/cluster/cluster.go

@@ -57,13 +57,6 @@ type AwareRunnable interface {
 	Disengage(context.Context, Cluster) error
 }
 
-// AwareDeepCopy is an interface that can be implemented by types
-// that are cluster-aware, and can return a copy of themselves
-// for a given cluster.
-type AwareDeepCopy[T any] interface {
-	DeepCopyFor(Cluster) T
-}
-
 // ByNameGetterFunc is a function that returns a cluster for a given identifying cluster name.
 type ByNameGetterFunc func(ctx context.Context, clusterName string) (Cluster, error)
 

pkg/handler/enqueue.go

@@ -127,6 +127,6 @@ func (e *EnqueueRequestForObject) Generic(ctx context.Context, evt event.Generic
 }
 
 // DeepCopyFor implements cluster.AwareDeepCopy[EventHandler].
-func (e *EnqueueRequestForObject) DeepCopyFor(c cluster.Cluster) EventHandler {
+func (e *EnqueueRequestForObject) DeepCopyFor(c cluster.Cluster) DeepCopyableEventHandler {
 	return &EnqueueRequestForObject{cluster: c}
 }

pkg/handler/enqueue_mapped.go

@@ -97,7 +97,7 @@ func (e *enqueueRequestsFromMapFunc) mapAndEnqueue(ctx context.Context, q workqu
 	}
 }
 
-func (e *enqueueRequestsFromMapFunc) DeepCopyFor(c cluster.Cluster) EventHandler {
+func (e *enqueueRequestsFromMapFunc) DeepCopyFor(c cluster.Cluster) DeepCopyableEventHandler {
 	return &enqueueRequestsFromMapFunc{
 		cluster:    c,
 		toRequests: e.toRequests,

pkg/handler/enqueue_owner.go

@@ -207,7 +207,7 @@ func (e *enqueueRequestForOwner) getOwnersReferences(object metav1.Object) []met
 	return nil
 }
 
-func (e *enqueueRequestForOwner) DeepCopyFor(c cluster.Cluster) EventHandler {
+func (e *enqueueRequestForOwner) DeepCopyFor(c cluster.Cluster) DeepCopyableEventHandler {
 	copy := &enqueueRequestForOwner{
 		cluster:      c,
 		ownerType:    e.ownerType,

pkg/handler/eventhandler.go

@@ -20,6 +20,7 @@ import (
 	"context"
 
 	"k8s.io/client-go/util/workqueue"
+	"sigs.k8s.io/controller-runtime/pkg/cluster"
 	"sigs.k8s.io/controller-runtime/pkg/event"
 )
 
@@ -56,6 +57,13 @@ type EventHandler interface {
 	Generic(context.Context, event.GenericEvent, workqueue.RateLimitingInterface)
 }
 
+// DeepCopyableEventHandler is an EventHandler that can be deep copied for use
+// in a different Cluster. This is used if a cluster provider is set in a manager.
+type DeepCopyableEventHandler interface {
+	EventHandler
+	DeepCopyFor(c cluster.Cluster) DeepCopyableEventHandler
+}
+
 var _ EventHandler = Funcs{}
 
 // Funcs implements EventHandler.

pkg/internal/controller/controller.go

@@ -32,7 +32,6 @@ import (
 	"sigs.k8s.io/controller-runtime/pkg/cluster"
 	"sigs.k8s.io/controller-runtime/pkg/handler"
 	ctrlmetrics "sigs.k8s.io/controller-runtime/pkg/internal/controller/metrics"
-	internal "sigs.k8s.io/controller-runtime/pkg/internal/source"
 	logf "sigs.k8s.io/controller-runtime/pkg/log"
 	"sigs.k8s.io/controller-runtime/pkg/predicate"
 	"sigs.k8s.io/controller-runtime/pkg/reconcile"
@@ -82,7 +81,7 @@ type Controller struct {
 	startWatches []*watchDescription
 
 	// clusterAwareWatches maintains a list of cluster aware sources, handlers, and predicates to start when the controller is started.
-	clusterAwareWatches []*watchDescription
+	clusterAwareWatches []*deepcopyableWatchDescription
 
 	// clustersByName is used to manage the fleet of clusters.
 	clustersByName map[string]*clusterDescription
@@ -124,37 +123,13 @@ type watchDescription struct {
 	predicates []predicate.Predicate
 }
 
-func (w *watchDescription) IsClusterAware() bool {
-	if _, ok := w.src.(cluster.AwareDeepCopy[*internal.Kind]); !ok {
-		if _, ok := w.src.(cluster.AwareDeepCopy[source.Source]); !ok {
-			return false
-		}
-	}
-	if _, ok := w.handler.(cluster.AwareDeepCopy[handler.EventHandler]); !ok {
-		return false
-	}
-	return true
-}
-
-func (w *watchDescription) DeepCopyFor(c cluster.Cluster) *watchDescription {
-	copy := &watchDescription{
-		predicates: w.predicates,
-	}
-	if clusterAwareSource, ok := w.src.(cluster.AwareDeepCopy[*internal.Kind]); ok {
-		copy.src = clusterAwareSource.DeepCopyFor(c)
-	} else if clusterAwareSource, ok := w.src.(cluster.AwareDeepCopy[source.Source]); ok {
-		copy.src = clusterAwareSource.DeepCopyFor(c)
-	} else {
-		return nil
-	}
-
-	if clusterAwareHandler, ok := w.handler.(cluster.AwareDeepCopy[handler.EventHandler]); ok {
-		copy.handler = clusterAwareHandler.DeepCopyFor(c)
-	} else {
-		return nil
-	}
-
-	return copy
+// deepcopyableWatchDescription contains all the information necessary to start
+// a watch. In addition to watchDescription it also contains the DeepCopyFor
+// method to adapt it to a different cluster.
+type deepcopyableWatchDescription struct {
+	src        source.DeepCopyableSyncingSource
+	handler    handler.DeepCopyableEventHandler
+	predicates []predicate.Predicate
 }
 
 // Reconcile implements reconcile.Reconciler.
@@ -182,14 +157,22 @@ func (c *Controller) Watch(src source.Source, evthdler handler.EventHandler, prc
 	c.mu.Lock()
 	defer c.mu.Unlock()
 
-	watchDesc := &watchDescription{src: src, handler: evthdler, predicates: prct}
-
 	// If the source is cluster aware, store it in a separate list.
-	_, forceDefaultClsuter := src.(ClusterAwareSource)
-	if c.WatchProviderClusters && !forceDefaultClsuter {
-		if !watchDesc.IsClusterAware() {
-			return fmt.Errorf("source %s is not cluster aware, but WatchProviderClusters is true", src)
+	var forceDefaultCluster bool
+	if src, ok := src.(ClusterAwareSource); ok {
+		forceDefaultCluster = src.ForceDefaultCluster()
+	}
+	if c.WatchProviderClusters && !forceDefaultCluster {
+		src, ok := src.(source.DeepCopyableSyncingSource)
+		if !ok {
+			return fmt.Errorf("source %T is not cluster aware, but WatchProviderClusters is true", src)
 		}
+		evthdler, ok := evthdler.(handler.DeepCopyableEventHandler)
+		if !ok {
+			return fmt.Errorf("handler %T is not cluster aware, but WatchProviderClusters is true", evthdler)
+		}
+
+		watchDesc := &deepcopyableWatchDescription{src: src, handler: evthdler, predicates: prct}
 		c.clusterAwareWatches = append(c.clusterAwareWatches, watchDesc)
 
 		// If the watch is cluster aware, start it for all the clusters
@@ -208,7 +191,7 @@ func (c *Controller) Watch(src source.Source, evthdler handler.EventHandler, prc
 	//
 	// These watches are going to be held on the controller struct until the manager or user calls Start(...).
 	if !c.Started {
-		c.startWatches = append(c.startWatches, watchDesc)
+		c.startWatches = append(c.startWatches, &watchDescription{src: src, handler: evthdler, predicates: prct})
 		return nil
 	}
 
@@ -260,8 +243,8 @@ func (c *Controller) Disengage(ctx context.Context, cluster cluster.Cluster) err
 	return nil
 }
 
-func (c *Controller) startClusterAwareWatchLocked(cldesc *clusterDescription, watchDesc *watchDescription) error {
-	watch := watchDesc.DeepCopyFor(cldesc)
+func (c *Controller) startClusterAwareWatchLocked(cldesc *clusterDescription, watchDesc *deepcopyableWatchDescription) error {
+	watch := &deepcopyableWatchDescription{src: watchDesc.src.DeepCopyFor(cldesc.Cluster), handler: watchDesc.handler.DeepCopyFor(cldesc.Cluster), predicates: watchDesc.predicates}
 	if watch == nil {
 		return nil
 	}

pkg/internal/source/kind.go

@@ -17,6 +17,20 @@ import (
 	"sigs.k8s.io/controller-runtime/pkg/predicate"
 )
 
+type Source interface {
+	Start(context.Context, handler.EventHandler, workqueue.RateLimitingInterface, ...predicate.Predicate) error
+}
+
+type SyncingSource interface {
+	Source
+	WaitForSync(ctx context.Context) error
+}
+
+type DeepCopyableSyncingSource interface {
+	SyncingSource
+	DeepCopyFor(cluster cluster.Cluster) DeepCopyableSyncingSource
+}
+
 // Kind is used to provide a source of events originating inside the cluster from Watches (e.g. Pod Create).
 type Kind struct {
 	// Type is the type of object to watch.  e.g. &v1.Pod{}
@@ -118,7 +132,7 @@ func (ks *Kind) WaitForSync(ctx context.Context) error {
 }
 
 // DeepCopyFor implements cluster.AwareDeepCopy[Source].
-func (ks *Kind) DeepCopyFor(c cluster.Cluster) *Kind {
+func (ks *Kind) DeepCopyFor(c cluster.Cluster) DeepCopyableSyncingSource {
 	return &Kind{
 		Type:  ks.Type,
 		Cache: c.GetCache(),

pkg/source/source.go

@@ -44,21 +44,18 @@ const (
 // * Use Channel for events originating outside the cluster (eh.g. GitHub Webhook callback, Polling external urls).
 //
 // Users may build their own Source implementations.
-type Source interface {
-	// Start is internal and should be called only by the Controller to register an EventHandler with the Informer
-	// to enqueue reconcile.Requests.
-	Start(context.Context, handler.EventHandler, workqueue.RateLimitingInterface, ...predicate.Predicate) error
-}
+type Source = internal.Source
 
 // SyncingSource is a source that needs syncing prior to being usable. The controller
 // will call its WaitForSync prior to starting workers.
-type SyncingSource interface {
-	Source
-	WaitForSync(ctx context.Context) error
-}
+type SyncingSource = internal.SyncingSource
+
+// DeepCopyableSyncingSource is a source that can be deep copied for a specific cluster.
+// It is used in setups with a cluster provider set in the manager.
+type DeepCopyableSyncingSource = internal.DeepCopyableSyncingSource
 
 // Kind creates a KindSource with the given cache provider.
-func Kind(cache cache.Cache, object client.Object) SyncingSource {
+func Kind(cache cache.Cache, object client.Object) DeepCopyableSyncingSource {
 	return &internal.Kind{Type: object, Cache: cache}
 }