fix issue 912: do dedupe with resourceVersion

Author: fishautumn

util/src/main/java/io/kubernetes/client/informer/cache/DeltaFIFO.java

@@ -29,6 +29,7 @@
 import java.util.function.Consumer;
 import java.util.function.Function;
 import org.apache.commons.collections4.CollectionUtils;
+import org.apache.commons.lang3.StringUtils;
 import org.apache.commons.lang3.tuple.MutablePair;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
@@ -443,7 +444,15 @@ private Deque<MutablePair<DeltaType, KubernetesObject>> combineDeltas(
    */
   private MutablePair<DeltaType, KubernetesObject> isDuplicate(
       MutablePair<DeltaType, KubernetesObject> d1, MutablePair<DeltaType, KubernetesObject> d2) {
-    return isDeletionDup(d1, d2);
+    MutablePair<DeltaType, KubernetesObject> deletionDelta = isDeletionDup(d1, d2);
+    if (deletionDelta != null) {
+      return deletionDelta;
+    }
+    if (d1.getLeft() != DeltaType.Deleted && d2.getLeft() != DeltaType.Deleted &&
+            StringUtils.equals(d1.getRight().getMetadata().getResourceVersion(), d2.getRight().getMetadata().getResourceVersion())) {
+      return d1;
+    }
+    return null;
   }
 
   /**

util/src/test/java/io/kubernetes/client/informer/cache/DeltaFIFOTest.java

@@ -20,6 +20,7 @@
 import io.kubernetes.client.openapi.models.V1ObjectMeta;
 import io.kubernetes.client.openapi.models.V1Pod;
 import java.util.Arrays;
+import java.util.Collections;
 import java.util.Deque;
 import java.util.LinkedList;
 import org.apache.commons.lang3.tuple.MutablePair;
@@ -94,7 +95,7 @@ public void testDeltaFIFOBasic() throws InterruptedException {
 
   @Test
   public void testDeltaFIFODedup() {
-    V1Pod foo1 = new V1Pod().metadata(new V1ObjectMeta().name("foo1").namespace("default"));
+    V1Pod foo1 = new V1Pod().metadata(new V1ObjectMeta().name("foo1").namespace("default").resourceVersion("ver"));
     Cache cache = new Cache();
     DeltaFIFO deltaFIFO = new DeltaFIFO(Caches::deletionHandlingMetaNamespaceKeyFunc, cache);
     Deque<MutablePair<DeltaFIFO.DeltaType, KubernetesObject>> deltas;
@@ -121,6 +122,12 @@ public void testDeltaFIFODedup() {
     assertEquals(foo1, deltas.peekFirst().getRight());
     assertEquals(2, deltas.size());
     deltaFIFO.getItems().remove(Caches.deletionHandlingMetaNamespaceKeyFunc(foo1));
+
+    // add-sync dedupe
+    deltaFIFO.add(foo1);
+    deltaFIFO.replace(Collections.singletonList(foo1), foo1.getMetadata().getResourceVersion());
+    deltas = deltaFIFO.getItems().get(Caches.deletionHandlingMetaNamespaceKeyFunc(foo1));
+    assertEquals(1, deltas.size());
   }
 
   @Test