refactor(resolver): make default resource variables immutable functions

Refactors `DefaultResourcesAdmin` and `DefaultResourcesEtcd` in the `resolver`
package from exported package-level variables to functions.

This change prevents consumers of the package from accidentally mutating the
global default state, which could have side effects on other parts of the
application.

Updates `resolver` logic and tests, as well as `cluster-handler` integration
tests, to invoke these functions instead of accessing variables directly.

Author: fernando-villalba

pkg/cluster-handler/controller/multigrescluster/integration_test.go

@@ -128,7 +128,7 @@ func TestMultigresClusterReconciliation(t *testing.T) {
 							Image:     "etcd:latest",
 							Replicas:  ptr.To(int32(3)), // Default from logic
 							Storage:   multigresv1alpha1.StorageSpec{Size: resolver.DefaultEtcdStorageSize},
-							Resources: resolver.DefaultResourcesEtcd,
+							Resources: resolver.DefaultResourcesEtcd(),
 						},
 					},
 				},
@@ -154,7 +154,7 @@ func TestMultigresClusterReconciliation(t *testing.T) {
 									{
 										Name:      "multiadmin",
 										Image:     "admin:latest",
-										Resources: resolver.DefaultResourcesAdmin,
+										Resources: resolver.DefaultResourcesAdmin(),
 									},
 								},
 							},

pkg/resolver/cluster.go

@@ -60,7 +60,7 @@ func (r *Resolver) PopulateClusterDefaults(cluster *multigresv1alpha1.MultigresC
 	if cluster.Spec.MultiAdmin.Spec != nil {
 		defaultStatelessSpec(
 			cluster.Spec.MultiAdmin.Spec,
-			DefaultResourcesAdmin,
+			DefaultResourcesAdmin(),
 			DefaultAdminReplicas,
 		)
 	}
@@ -93,8 +93,8 @@ func defaultEtcdSpec(spec *multigresv1alpha1.EtcdSpec) {
 		spec.Replicas = &r
 	}
 	if isResourcesEmpty(spec.Resources) {
-		// Safety: Must DeepCopy global default to avoid shared mutable state
-		spec.Resources = *DefaultResourcesEtcd.DeepCopy()
+		// Safety: DefaultResourcesEtcd() returns a fresh struct, so no DeepCopy needed.
+		spec.Resources = DefaultResourcesEtcd()
 	}
 }
 
@@ -108,7 +108,8 @@ func defaultStatelessSpec(
 		spec.Replicas = &defaultReplicas
 	}
 	if isResourcesEmpty(spec.Resources) {
-		// Safety: Must DeepCopy global default to avoid shared mutable state
+		// Safety: We assume defaultRes is passed by value (a fresh copy from the default function).
+		// We perform a DeepCopy to ensure spec.Resources owns its own maps, independent of the input defaultRes.
 		spec.Resources = *defaultRes.DeepCopy()
 	}
 }
@@ -208,7 +209,7 @@ func ResolveMultiAdmin(
 	}
 
 	// 2. Apply Deep Defaults
-	defaultStatelessSpec(finalSpec, DefaultResourcesAdmin, DefaultAdminReplicas)
+	defaultStatelessSpec(finalSpec, DefaultResourcesAdmin(), DefaultAdminReplicas)
 
 	return finalSpec
 }

pkg/resolver/cluster_test.go

@@ -115,14 +115,14 @@ func TestResolver_PopulateClusterDefaults(t *testing.T) {
 						Etcd: &multigresv1alpha1.EtcdSpec{
 							Image:     DefaultEtcdImage,
 							Replicas:  ptr.To(DefaultEtcdReplicas),
-							Resources: DefaultResourcesEtcd,
+							Resources: DefaultResourcesEtcd(),
 							Storage:   multigresv1alpha1.StorageSpec{Size: DefaultEtcdStorageSize},
 						},
 					},
 					MultiAdmin: multigresv1alpha1.MultiAdminConfig{
 						Spec: &multigresv1alpha1.StatelessSpec{
 							Replicas:  ptr.To(DefaultAdminReplicas),
-							Resources: DefaultResourcesAdmin,
+							Resources: DefaultResourcesAdmin(),
 						},
 					},
 				},
@@ -199,7 +199,7 @@ func TestResolver_PopulateClusterDefaults(t *testing.T) {
 						Etcd: &multigresv1alpha1.EtcdSpec{
 							Image:     "custom-etcd",
 							Replicas:  ptr.To(DefaultEtcdReplicas),
-							Resources: DefaultResourcesEtcd,
+							Resources: DefaultResourcesEtcd(),
 							Storage:   multigresv1alpha1.StorageSpec{Size: DefaultEtcdStorageSize},
 						},
 					},
@@ -344,7 +344,7 @@ func TestResolveGlobalTopo(t *testing.T) {
 				Etcd: &multigresv1alpha1.EtcdSpec{
 					Image:     "inline",
 					Replicas:  ptr.To(DefaultEtcdReplicas),
-					Resources: DefaultResourcesEtcd,
+					Resources: DefaultResourcesEtcd(),
 					Storage:   multigresv1alpha1.StorageSpec{Size: DefaultEtcdStorageSize},
 				},
 			},
@@ -375,7 +375,7 @@ func TestResolveGlobalTopo(t *testing.T) {
 				Etcd: &multigresv1alpha1.EtcdSpec{
 					Image:     "template",
 					Replicas:  ptr.To(DefaultEtcdReplicas),
-					Resources: DefaultResourcesEtcd,
+					Resources: DefaultResourcesEtcd(),
 					Storage:   multigresv1alpha1.StorageSpec{Size: DefaultEtcdStorageSize},
 				},
 			},
@@ -391,7 +391,7 @@ func TestResolveGlobalTopo(t *testing.T) {
 				Etcd: &multigresv1alpha1.EtcdSpec{
 					Image:     DefaultEtcdImage,
 					Replicas:  ptr.To(DefaultEtcdReplicas),
-					Resources: DefaultResourcesEtcd,
+					Resources: DefaultResourcesEtcd(),
 					Storage:   multigresv1alpha1.StorageSpec{Size: DefaultEtcdStorageSize},
 				},
 			},
@@ -403,7 +403,7 @@ func TestResolveGlobalTopo(t *testing.T) {
 				Etcd: &multigresv1alpha1.EtcdSpec{
 					Image:     DefaultEtcdImage,
 					Replicas:  ptr.To(DefaultEtcdReplicas),
-					Resources: DefaultResourcesEtcd,
+					Resources: DefaultResourcesEtcd(),
 					Storage:   multigresv1alpha1.StorageSpec{Size: DefaultEtcdStorageSize},
 				},
 			},
@@ -436,7 +436,7 @@ func TestResolveMultiAdmin(t *testing.T) {
 			tpl: nil,
 			want: &multigresv1alpha1.StatelessSpec{
 				Replicas:  ptr.To(int32(5)),
-				Resources: DefaultResourcesAdmin,
+				Resources: DefaultResourcesAdmin(),
 			},
 		},
 		"Template Fallback": {
@@ -448,7 +448,7 @@ func TestResolveMultiAdmin(t *testing.T) {
 			},
 			want: &multigresv1alpha1.StatelessSpec{
 				Replicas:  ptr.To(int32(3)),
-				Resources: DefaultResourcesAdmin,
+				Resources: DefaultResourcesAdmin(),
 			},
 		},
 		"Template Found but Nil Content": {
@@ -460,15 +460,15 @@ func TestResolveMultiAdmin(t *testing.T) {
 			},
 			want: &multigresv1alpha1.StatelessSpec{
 				Replicas:  ptr.To(DefaultAdminReplicas),
-				Resources: DefaultResourcesAdmin,
+				Resources: DefaultResourcesAdmin(),
 			},
 		},
 		"No-op (Nil Template)": {
 			spec: &multigresv1alpha1.MultiAdminConfig{},
 			tpl:  nil,
 			want: &multigresv1alpha1.StatelessSpec{
 				Replicas:  ptr.To(DefaultAdminReplicas),
-				Resources: DefaultResourcesAdmin,
+				Resources: DefaultResourcesAdmin(),
 			},
 		},
 	}

pkg/resolver/defaults.go

@@ -46,13 +46,10 @@ const (
 	DefaultEtcdStorageSize = "1Gi"
 )
 
-// Resource Defaults (Computed variables for reuse).
-// Note: These are declared as variables because Go does not support const structs,
-// but they should be treated as immutable.
-var (
-	// DefaultResourcesAdmin defines the default resource requests and limits for the MultiAdmin deployment.
-	// It requests 100m CPU and 128Mi memory, with a limit of 256Mi memory.
-	DefaultResourcesAdmin = corev1.ResourceRequirements{
+// DefaultResourcesAdmin returns the default resource requests and limits for the MultiAdmin deployment.
+// It requests 100m CPU and 128Mi memory, with a limit of 256Mi memory.
+func DefaultResourcesAdmin() corev1.ResourceRequirements {
+	return corev1.ResourceRequirements{
 		Requests: corev1.ResourceList{
 			corev1.ResourceCPU:    resource.MustParse("100m"),
 			corev1.ResourceMemory: resource.MustParse("128Mi"),
@@ -61,10 +58,12 @@ var (
 			corev1.ResourceMemory: resource.MustParse("256Mi"),
 		},
 	}
+}
 
-	// DefaultResourcesEtcd defines the default resource requests and limits for the managed Etcd cluster.
-	// It requests 100m CPU and 256Mi memory, with a limit of 512Mi memory.
-	DefaultResourcesEtcd = corev1.ResourceRequirements{
+// DefaultResourcesEtcd returns the default resource requests and limits for the managed Etcd cluster.
+// It requests 100m CPU and 256Mi memory, with a limit of 512Mi memory.
+func DefaultResourcesEtcd() corev1.ResourceRequirements {
+	return corev1.ResourceRequirements{
 		Requests: corev1.ResourceList{
 			corev1.ResourceCPU:    resource.MustParse("100m"),
 			corev1.ResourceMemory: resource.MustParse("256Mi"),
@@ -73,4 +72,4 @@ var (
 			corev1.ResourceMemory: resource.MustParse("512Mi"),
 		},
 	}
-)
+}