[v0.15] Fix namespace label equality check and nil map panic (#5172)

* Fix namespace label equality check before update

Compare the computed desired state against the current namespace
labels and annotations instead of comparing raw options directly.
The previous reflect.DeepEqual check could never return true because
ns.Labels always includes kubernetes.io/metadata.name (and now also
preserved pod-security labels), causing an unnecessary updateNamespace
call on every reconcile even when no label changes were needed.

* Fix nil map panic and update addLabelsFromOptions doc comment

addLabelsFromOptions panics when ns.Labels is nil (maps.Clone returns
nil) and NamespaceLabels options are non-nil. Add the same nil guard
already present for annotations.

Update the function doc comment to reflect the actual label retention
rules: options labels, kubernetes.io/metadata.name, and existing
pod-security.kubernetes.io/* labels are preserved; pod-security labels
from options are ignored.

Author: thardeck

internal/cmd/agent/deployer/deployer.go

@@ -4,7 +4,7 @@ import (
 	"context"
 	"errors"
 	"fmt"
-	"reflect"
+	"maps"
 	"regexp"
 	"strings"
 
@@ -197,25 +197,28 @@ func (d *Deployer) setNamespaceLabelsAndAnnotations(ctx context.Context, bd *fle
 		return err
 	}
 
-	if reflect.DeepEqual(bd.Spec.Options.NamespaceLabels, ns.Labels) && reflect.DeepEqual(bd.Spec.Options.NamespaceAnnotations, ns.Annotations) {
-		return nil
-	}
-
+	desiredLabels := maps.Clone(ns.Labels)
 	if bd.Spec.Options.NamespaceLabels != nil {
-		addLabelsFromOptions(log.FromContext(ctx), ns.Labels, bd.Spec.Options.NamespaceLabels)
+		if desiredLabels == nil {
+			desiredLabels = make(map[string]string)
+		}
+		addLabelsFromOptions(log.FromContext(ctx), desiredLabels, bd.Spec.Options.NamespaceLabels)
 	}
+	desiredAnnotations := maps.Clone(ns.Annotations)
 	if bd.Spec.Options.NamespaceAnnotations != nil {
-		if ns.Annotations == nil {
-			ns.Annotations = map[string]string{}
+		if desiredAnnotations == nil {
+			desiredAnnotations = make(map[string]string)
 		}
-		addAnnotationsFromOptions(ns.Annotations, bd.Spec.Options.NamespaceAnnotations)
+		addAnnotationsFromOptions(desiredAnnotations, bd.Spec.Options.NamespaceAnnotations)
 	}
-	err = d.updateNamespace(ctx, ns)
-	if err != nil {
-		return err
+
+	if maps.Equal(desiredLabels, ns.Labels) && maps.Equal(desiredAnnotations, ns.Annotations) {
+		return nil
 	}
 
-	return nil
+	ns.Labels = desiredLabels
+	ns.Annotations = desiredAnnotations
+	return d.updateNamespace(ctx, ns)
 }
 
 // updateNamespace updates a namespace resource in the cluster.
@@ -242,7 +245,10 @@ func (d *Deployer) fetchNamespace(ctx context.Context, releaseID string) (*corev
 
 const podSecurityLabelPrefix = "pod-security.kubernetes.io/"
 
-// addLabelsFromOptions updates nsLabels so that it only contains all labels specified in optLabels, plus the `kubernetes.io/metadata.name` labels added by kubernetes when creating the namespace.
+// addLabelsFromOptions updates nsLabels to contain labels from optLabels, while preserving
+// the `kubernetes.io/metadata.name` label added by Kubernetes when creating the namespace
+// and any existing `pod-security.kubernetes.io/*` labels. Labels with the
+// `pod-security.kubernetes.io/` prefix in optLabels are ignored.
 func addLabelsFromOptions(logger logr.Logger, nsLabels map[string]string, optLabels map[string]string) {
 	for k, v := range optLabels {
 		if strings.HasPrefix(k, podSecurityLabelPrefix) {