shallow copy on sets (#548)

* shallow copy on sets

* add unit tests

* check for same pointers in shallow copy

* update

* update

* goimports

changelog/v0.38.4/sets-shallowcopy.yaml

@@ -0,0 +1,6 @@
+changelog:
+  - type: NON_USER_FACING
+    issueLink: 
+    description: >
+      ""
+    skipCI: "false"

contrib/pkg/sets/v2/sets.go

@@ -67,6 +67,8 @@ type ResourceSet[T client.Object] interface {
 	Generic() sk_sets.ResourceSet
 	// Clone returns a deep copy of the set
 	Clone() ResourceSet[T]
+	// ShallowCopy returns a shallow copy of the set
+	ShallowCopy() ResourceSet[T]
 }
 
 // ResourceDelta represents the set of changes between two ResourceSets.
@@ -335,6 +337,14 @@ func (oldSet *resourceSet[T]) Clone() ResourceSet[T] {
 	return new
 }
 
+func (oldSet *resourceSet[T]) ShallowCopy() ResourceSet[T] {
+	newSet := make([]T, len(oldSet.set))
+	copy(newSet, oldSet.set)
+	return &resourceSet[T]{
+		set: newSet,
+	}
+}
+
 func (s *resourceSet[T]) Generic() sk_sets.ResourceSet {
 	set := sk_sets.NewResourceSet(nil)
 	s.Iter(func(_ int, v T) bool {

contrib/tests/set_v2_test.go

@@ -110,6 +110,29 @@ var _ = Describe("PaintSetV2", func() {
 		})
 	})
 
+	It("should shallow copy", func() {
+		newPaint := &v1.Paint{
+			ObjectMeta: metav1.ObjectMeta{Name: "newPaint", Namespace: "newPaint"},
+		}
+		setA.Insert(paintA, paintBCluster2, paintC, newPaint)
+		Expect(setA.Has(newPaint)).To(BeTrue())
+		Expect(setA.Len()).To(Equal(4))
+
+		setB = setA.ShallowCopy()
+		Expect(setB.Has(newPaint)).To(BeTrue())
+		// want to make sure that the pointers are the same in both sets
+		// without having to construct a new list, so we just iterate
+		setB.Iter(func(i int, p *v1.Paint) bool {
+			setA.Iter(func(j int, p2 *v1.Paint) bool {
+				if i == j {
+					Expect(p == p2).To(BeTrue())
+				}
+				return true
+			})
+			return true
+		})
+	})
+
 	It("should double filter List", func() {
 		setA.Insert(paintA, paintBCluster2, paintC)
 		Expect(setA.Has(paintA)).To(BeTrue())