pkg/listwatch: Change to accept single instance of rvs

Author: lilic

pkg/listwatch/listwatch.go

@@ -169,14 +169,14 @@ func (mlw multiListerWatcher) List(options metav1.ListOptions) (runtime.Object,
 // It returns a watch.Interface that combines the output from the
 // watch.Interface of every cache.ListerWatcher into a single result chan.
 func (mlw multiListerWatcher) Watch(options metav1.ListOptions) (watch.Interface, error) {
-	resourceVersions := make([]string, len(mlw))
+	var resourceVersions string
 	// Allow resource versions to be "".
 	if options.ResourceVersion != "" {
 		rvs := strings.Split(options.ResourceVersion, "/")
-		if len(rvs) != 1 {
-			return nil, fmt.Errorf("expected resource version to have 1 parts to match the number of ListerWatchers, got %d", len(rvs))
+		if len(rvs) > 1 {
+			return nil, fmt.Errorf("expected resource version to have 1 part, got %d", len(rvs))
 		}
-		resourceVersions = rvs
+		resourceVersions = options.ResourceVersion
 	}
 	return newMultiWatch(mlw, resourceVersions, options)
 }
@@ -190,9 +190,8 @@ type multiWatch struct {
 }
 
 // newMultiWatch returns a new multiWatch or an error if one of the underlying
-// Watch funcs errored. The length of []cache.ListerWatcher and []string must
-// match.
-func newMultiWatch(lws []cache.ListerWatcher, resourceVersions []string, options metav1.ListOptions) (*multiWatch, error) {
+// Watch funcs errored.
+func newMultiWatch(lws []cache.ListerWatcher, resourceVersions string, options metav1.ListOptions) (*multiWatch, error) {
 	var (
 		result   = make(chan watch.Event)
 		stopped  = make(chan struct{})
@@ -204,7 +203,7 @@ func newMultiWatch(lws []cache.ListerWatcher, resourceVersions []string, options
 
 	for _, lw := range lws {
 		o := options.DeepCopy()
-		o.ResourceVersion = resourceVersions[0]
+		o.ResourceVersion = resourceVersions
 		w, err := lw.Watch(*o)
 		if err != nil {
 			return nil, err

pkg/listwatch/listwatch_test.go

@@ -26,11 +26,7 @@ import (
 
 var _ watch.Interface = &multiWatch{}
 
-func setupMultiWatch(n int, t *testing.T, rvs ...string) ([]*watch.FakeWatcher, *multiWatch) {
-	// Default resource versions to the correct length if none were passed.
-	if len(rvs) == 0 {
-		rvs = make([]string, n)
-	}
+func setupMultiWatch(n int, t *testing.T, rvs string) ([]*watch.FakeWatcher, *multiWatch) {
 	ws := make([]*watch.FakeWatcher, n)
 	lws := make([]cache.ListerWatcher, n)
 	for i := range ws {
@@ -48,28 +44,19 @@ func setupMultiWatch(n int, t *testing.T, rvs ...string) ([]*watch.FakeWatcher,
 }
 
 func TestNewMultiWatch(t *testing.T) {
-	func() {
-		defer func() {
-			if r := recover(); r == nil {
-				t.Error("expected newMultiWatch to panic when number of resource versions is less than ListerWatchers")
-			}
-		}()
-		// Create a multiWatch from 2 ListerWatchers but only pass 1 resource version.
-		_, _ = setupMultiWatch(2, t, "1")
-	}()
 	func() {
 		defer func() {
 			if r := recover(); r != nil {
 				t.Errorf("newMultiWatch should not panic when number of resource versions matches ListerWatchers; got: %v", r)
 			}
 		}()
-		// Create a multiWatch from 2 ListerWatchers and pass 2 resource versions.
-		_, _ = setupMultiWatch(2, t, "1", "2")
+		// Create a multiWatch from 1 ListerWatchers and pass 1 resource versions.
+		_, _ = setupMultiWatch(1, t, "1")
 	}()
 }
 
 func TestMultiWatchResultChan(t *testing.T) {
-	ws, m := setupMultiWatch(10, t)
+	ws, m := setupMultiWatch(10, t, "10")
 	defer m.Stop()
 	var events []watch.Event
 	var wg sync.WaitGroup
@@ -97,7 +84,7 @@ func TestMultiWatchResultChan(t *testing.T) {
 }
 
 func TestMultiWatchStop(t *testing.T) {
-	ws, m := setupMultiWatch(10, t)
+	ws, m := setupMultiWatch(10, t, "10")
 	m.Stop()
 	var stopped int
 	for _, w := range ws {
@@ -149,7 +136,7 @@ func TestRacyMultiWatch(t *testing.T) {
 
 	mw, err := newMultiWatch(
 		[]cache.ListerWatcher{lw},
-		[]string{"foo"},
+		"foo",
 		metav1.ListOptions{},
 	)
 	if err != nil {