⚠ fix: Stop accumulating lists in multi-namespace cache implementation (#3195)

* fix: prevent list accumulation in multi-namespace cache implementation

Signed-off-by: Xuhui zhang <[email protected]>

* Add test

Signed-off-by: Xuhui zhang <[email protected]>

---------

Signed-off-by: Xuhui zhang <[email protected]>

Author: zxh326

pkg/cache/cache_test.go

@@ -1035,13 +1035,15 @@ func CacheTest(createCacheFunc func(config *rest.Config, opts cache.Options) (ca
 							Version: "v1",
 							Kind:    "PodList",
 						})
-						Expect(namespacedCache.List(context.Background(), out)).To(Succeed())
-
-						By("verifying the returned pod is from the watched namespace")
-						Expect(out.Items).NotTo(BeEmpty())
-						Expect(out.Items).Should(HaveLen(2))
-						for _, item := range out.Items {
-							Expect(item.GetNamespace()).To(Equal(testNamespaceOne))
+						for range 2 {
+							Expect(namespacedCache.List(context.Background(), out)).To(Succeed())
+
+							By("verifying the returned pod is from the watched namespace")
+							Expect(out.Items).NotTo(BeEmpty())
+							Expect(out.Items).Should(HaveLen(2))
+							for _, item := range out.Items {
+								Expect(item.GetNamespace()).To(Equal(testNamespaceOne))
+							}
 						}
 						By("listing all nodes - should still be able to list a cluster-scoped resource")
 						nodeList := &unstructured.UnstructuredList{}

pkg/cache/multi_namespace_cache.go

@@ -279,10 +279,7 @@ func (c *multiNamespaceCache) List(ctx context.Context, list client.ObjectList,
 		return err
 	}
 
-	allItems, err := apimeta.ExtractList(list)
-	if err != nil {
-		return err
-	}
+	allItems := []runtime.Object{}
 
 	limitSet := listOpts.Limit > 0