Fix a bug with Limit list opt. (#1618)

Previously, `Limit(n)` only looks at the first `n` objects. This could cause `List` to return less than `n` objects if other `opts` apply further filtering, even though there are more than `n` total number of objects matching the list options.

pkg/cache/cache_test.go

@@ -312,6 +312,15 @@ func CacheTest(createCacheFunc func(config *rest.Config, opts cache.Options) (ca
 					Expect(informerCache.List(context.Background(), listObj, opts)).To(Succeed())
 					Expect(listObj.Items).Should(HaveLen(3))
 				})
+
+				It("should return a limited result set matching the correct label", func() {
+					listObj := &corev1.PodList{}
+					labelOpt := client.MatchingLabels(map[string]string{"common-label": "common"})
+					limitOpt := client.Limit(1)
+					By("verifying that only Limit (1) number of objects are retrieved from the cache")
+					Expect(informerCache.List(context.Background(), listObj, labelOpt, limitOpt)).To(Succeed())
+					Expect(listObj.Items).Should(HaveLen(1))
+				})
 			})
 
 			Context("with unstructured objects", func() {

pkg/cache/internal/cache_reader.go

@@ -129,10 +129,10 @@ func (c *CacheReader) List(_ context.Context, out client.ObjectList, opts ...cli
 	limitSet := listOpts.Limit > 0
 
 	runtimeObjs := make([]runtime.Object, 0, len(objs))
-	for i, item := range objs {
+	for _, item := range objs {
 		// if the Limit option is set and the number of items
 		// listed exceeds this limit, then stop reading.
-		if limitSet && int64(i) >= listOpts.Limit {
+		if limitSet && int64(len(runtimeObjs)) >= listOpts.Limit {
 			break
 		}
 		obj, isObj := item.(runtime.Object)