Bump sigs.k8s.io/structured-merge-diff to v3

vendor/sigs.k8s.io/structured-merge-diff/v3/fieldpath/managers.go

@@ -58,6 +58,37 @@ func (v versionedSet) Applied() bool {
 // what version).
 type ManagedFields map[string]VersionedSet
 
+// Equals returns true if the two managedfields are the same, false
+// otherwise.
+func (lhs ManagedFields) Equals(rhs ManagedFields) bool {
+	if len(lhs) != len(rhs) {
+		return false
+	}
+
+	for manager, left := range lhs {
+		right, ok := rhs[manager]
+		if !ok {
+			return false
+		}
+		if left.APIVersion() != right.APIVersion() || left.Applied() != right.Applied() {
+			return false
+		}
+		if !left.Set().Equals(right.Set()) {
+			return false
+		}
+	}
+	return true
+}
+
+// Copy the list, this is mostly a shallow copy.
+func (lhs ManagedFields) Copy() ManagedFields {
+	copy := ManagedFields{}
+	for manager, set := range lhs {
+		copy[manager] = set
+	}
+	return copy
+}
+
 // Difference returns a symmetric difference between two Managers. If a
 // given user's entry has version X in lhs and version Y in rhs, then
 // the return value for that user will be from rhs. If the difference for

vendor/sigs.k8s.io/structured-merge-diff/v3/merge/update.go

@@ -148,7 +148,8 @@ func (s *Updater) Update(liveObject, newObject *typed.TypedValue, version fieldp
 
 // Apply should be called when Apply is run, given the current object as
 // well as the configuration that is applied. This will merge the object
-// and return it.
+// and return it. If the object hasn't changed, nil is returned (the
+// managers can still have changed though).
 func (s *Updater) Apply(liveObject, configObject *typed.TypedValue, version fieldpath.APIVersion, managers fieldpath.ManagedFields, manager string, force bool) (*typed.TypedValue, fieldpath.ManagedFields, error) {
 	managers = shallowCopyManagers(managers)
 	var err error
@@ -178,10 +179,13 @@ func (s *Updater) Apply(liveObject, configObject *typed.TypedValue, version fiel
 	if err != nil {
 		return nil, fieldpath.ManagedFields{}, fmt.Errorf("failed to prune fields: %v", err)
 	}
-	managers, _, err = s.update(liveObject, newObject, version, managers, manager, force)
+	managers, compare, err := s.update(liveObject, newObject, version, managers, manager, force)
 	if err != nil {
 		return nil, fieldpath.ManagedFields{}, err
 	}
+	if compare.IsSame() {
+		newObject = nil
+	}
 	return newObject, managers, nil
 }