fix: httproute status.parents is not cleaned up

internal/provider/kubernetes/status.go

@@ -501,12 +501,34 @@
 
 // mergeRouteParentStatus merges the old and new RouteParentStatus.
 // This is needed because the RouteParentStatus doesn't support strategic merge patch yet.
+// It also removes any status.parents entries that are no longer referenced in the route's spec.parentRefs.
 func mergeRouteParentStatus(ns string, old, new []gwapiv1.RouteParentStatus) []gwapiv1.RouteParentStatus {
-	merged := make([]gwapiv1.RouteParentStatus, len(old))
-	_ = copy(merged, old)
+	// First, create a map of all parentRefs in the new status
+	// These represent the current valid parentRefs from spec.parentRefs
+	newParentRefs := make(map[string]bool)
+	for _, parent := range new {
+		// Create a unique key for each parentRef
+		key := parentRefToString(parent.ParentRef, ns)
+		newParentRefs[key] = true
+	}
+
+	// Filter out old entries that are no longer referenced in spec.parentRefs
+	var filteredOld []gwapiv1.RouteParentStatus
+	for _, existing := range old {
+		key := parentRefToString(existing.ParentRef, ns)
+		if newParentRefs[key] {
+			// Keep this entry as it's still referenced
+			filteredOld = append(filteredOld, existing)
+		}
+		// Skip entries that are no longer referenced
+	}
+
+	// Now merge the filtered old entries with the new ones
+	merged := make([]gwapiv1.RouteParentStatus, len(filteredOld))
+	_ = copy(merged, filteredOld)
 	for _, parent := range new {
 		found := -1
-		for i, existing := range old {
+		for i, existing := range filteredOld {
 			if isParentRefEqual(parent.ParentRef, existing.ParentRef, ns) {
 				found = i
 				break
@@ -521,6 +543,30 @@
 	return merged
 }
 
+// parentRefToString creates a unique string representation of a ParentReference
+func parentRefToString(ref gwapiv1.ParentReference, routeNS string) string {
+	defaultGroup := (*gwapiv1.Group)(&gwapiv1.GroupVersion.Group)
+	group := defaultGroup
+	if ref.Group != nil {
+		group = ref.Group
+	}
+
+	defaultKind := gwapiv1.Kind(resource.KindGateway)
+	kind := &defaultKind
+	if ref.Kind != nil {
+		kind = ref.Kind
+	}
+
+	// If the parent's namespace is not set, default to the namespace of the Route.
+	defaultNS := gwapiv1.Namespace(routeNS)
+	namespace := &defaultNS
+	if ref.Namespace != nil {
+		namespace = ref.Namespace
+	}
+
+	return fmt.Sprintf("%s/%s/%s/%s", *group, *kind, *namespace, ref.Name)
+}
+
 func isParentRefEqual(ref1, ref2 gwapiv1.ParentReference, routeNS string) bool {
 	defaultGroup := (*gwapiv1.Group)(&gwapiv1.GroupVersion.Group)
 	if ref1.Group == nil {

internal/provider/kubernetes/status_cleanup_test.go

@@ -0,0 +1,174 @@
+// Copyright Envoy Gateway Authors
+// SPDX-License-Identifier: Apache-2.0
+// The full text of the Apache license is available in the LICENSE file at
+// the root of the repo.
+
+package kubernetes
+
+import (
+	"reflect"
+	"testing"
+
+	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
+	"k8s.io/utils/ptr"
+	gwapiv1 "sigs.k8s.io/gateway-api/apis/v1"
+)
+
+func Test_mergeRouteParentStatusCleanup(t *testing.T) {
+	type args struct {
+		ns  string
+		old []gwapiv1.RouteParentStatus
+		new []gwapiv1.RouteParentStatus
+	}
+	tests := []struct {
+		name string
+		args args
+		want []gwapiv1.RouteParentStatus
+	}{
+		{
+			name: "remove old entries that are no longer referenced",
+			args: args{
+				ns: "default",
+				old: []gwapiv1.RouteParentStatus{
+					{
+						ControllerName: "gateway.envoyproxy.io/gatewayclass-controller",
+						ParentRef: gwapiv1.ParentReference{
+							Name:      "gateway1",
+							Namespace: ptr.To[gwapiv1.Namespace]("default"),
+						},
+						Conditions: []metav1.Condition{
+							{
+								Type:   string(gwapiv1.RouteConditionAccepted),
+								Status: metav1.ConditionTrue,
+								Reason: "Accepted",
+							},
+						},
+					},
+					{
+						ControllerName: "gateway.envoyproxy.io/gatewayclass-controller",
+						ParentRef: gwapiv1.ParentReference{
+							Name:      "gateway2",
+							Namespace: ptr.To[gwapiv1.Namespace]("default"),
+						},
+						Conditions: []metav1.Condition{
+							{
+								Type:   string(gwapiv1.RouteConditionAccepted),
+								Status: metav1.ConditionTrue,
+								Reason: "OldReason",
+							},
+						},
+					},
+				},
+				new: []gwapiv1.RouteParentStatus{
+					{
+						ControllerName: "gateway.envoyproxy.io/gatewayclass-controller",
+						ParentRef: gwapiv1.ParentReference{
+							Name:      "gateway1",
+							Namespace: ptr.To[gwapiv1.Namespace]("default"),
+						},
+						Conditions: []metav1.Condition{
+							{
+								Type:   string(gwapiv1.RouteConditionAccepted),
+								Status: metav1.ConditionTrue,
+								Reason: "Accepted",
+							},
+						},
+					},
+					// gateway2 is removed from spec.parentRefs, so it should not appear in the merged result
+				},
+			},
+			want: []gwapiv1.RouteParentStatus{
+				{
+					ControllerName: "gateway.envoyproxy.io/gatewayclass-controller",
+					ParentRef: gwapiv1.ParentReference{
+						Name:      "gateway1",
+						Namespace: ptr.To[gwapiv1.Namespace]("default"),
+					},
+					Conditions: []metav1.Condition{
+						{
+							Type:   string(gwapiv1.RouteConditionAccepted),
+							Status: metav1.ConditionTrue,
+							Reason: "Accepted",
+						},
+					},
+				},
+			},
+		},
+		{
+			name: "update existing entry and keep only referenced entries",
+			args: args{
+				ns: "default",
+				old: []gwapiv1.RouteParentStatus{
+					{
+						ControllerName: "gateway.envoyproxy.io/gatewayclass-controller",
+						ParentRef: gwapiv1.ParentReference{
+							Name:      "gateway1",
+							Namespace: ptr.To[gwapiv1.Namespace]("default"),
+						},
+						Conditions: []metav1.Condition{
+							{
+								Type:   string(gwapiv1.RouteConditionAccepted),
+								Status: metav1.ConditionTrue,
+								Reason: "OldReason",
+							},
+						},
+					},
+					{
+						ControllerName: "gateway.envoyproxy.io/gatewayclass-controller",
+						ParentRef: gwapiv1.ParentReference{
+							Name:      "gateway2",
+							Namespace: ptr.To[gwapiv1.Namespace]("default"),
+						},
+						Conditions: []metav1.Condition{
+							{
+								Type:   string(gwapiv1.RouteConditionAccepted),
+								Status: metav1.ConditionTrue,
+								Reason: "OldReason",
+							},
+						},
+					},
+				},
+				new: []gwapiv1.RouteParentStatus{
+					{
+						ControllerName: "gateway.envoyproxy.io/gatewayclass-controller",
+						ParentRef: gwapiv1.ParentReference{
+							Name:      "gateway1",
+							Namespace: ptr.To[gwapiv1.Namespace]("default"),
+						},
+						Conditions: []metav1.Condition{
+							{
+								Type:   string(gwapiv1.RouteConditionAccepted),
+								Status: metav1.ConditionTrue,
+								Reason: "NewReason",
+							},
+						},
+					},
+					// gateway2 is removed from spec.parentRefs, so it should not appear in the merged result
+				},
+			},
+			want: []gwapiv1.RouteParentStatus{
+				{
+					ControllerName: "gateway.envoyproxy.io/gatewayclass-controller",
+					ParentRef: gwapiv1.ParentReference{
+						Name:      "gateway1",
+						Namespace: ptr.To[gwapiv1.Namespace]("default"),
+					},
+					Conditions: []metav1.Condition{
+						{
+							Type:   string(gwapiv1.RouteConditionAccepted),
+							Status: metav1.ConditionTrue,
+							Reason: "NewReason",
+						},
+					},
+				},
+			},
+		},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			if got := mergeRouteParentStatus(tt.args.ns, tt.args.old, tt.args.new); !reflect.DeepEqual(got, tt.want) {
+				t.Errorf("mergeRouteParentStatus() = %v, want %v", got, tt.want)
+			}
+		})
+	}
+}