fix #5102: accounting for null replicas

Author: shawkins

CHANGELOG.md

@@ -3,6 +3,7 @@
 ### 6.7-SNAPSHOT
 
 #### Bugs
+* Fix #5102: wait on scale to 0 was not completing
 
 #### Improvements
 

kubernetes-client/src/main/java/io/fabric8/kubernetes/client/dsl/internal/HasMetadataOperation.java

@@ -34,7 +34,7 @@
 import org.slf4j.LoggerFactory;
 
 import java.io.IOException;
-import java.util.Objects;
+import java.util.Optional;
 import java.util.concurrent.CompletableFuture;
 import java.util.concurrent.TimeUnit;
 import java.util.concurrent.atomic.AtomicReference;
@@ -309,7 +309,7 @@ public Scale scale(Scale scaleParam) {
   /**
    * Let's wait until there are enough Ready pods.
    */
-  protected void waitUntilScaled(final Integer count) {
+  protected void waitUntilScaled(final int count) {
     final AtomicReference<Integer> replicasRef = new AtomicReference<>(0);
 
     final String name = checkName(getItem());
@@ -319,11 +319,13 @@ protected void waitUntilScaled(final Integer count) {
     Utils.scheduleWithVariableRate(completion, getOperationContext().getExecutor(), () -> {
       try {
         Scale scale = scale();
-        if (Objects.equals(count, scale.getStatus().getReplicas()) && Objects.equals(count, scale.getSpec().getReplicas())) {
+        int statusReplicas = Optional.ofNullable(scale.getStatus().getReplicas()).orElse(0);
+        int specReplicas = Optional.ofNullable(scale.getSpec().getReplicas()).orElse(0);
+        if (count == statusReplicas && count == specReplicas) {
           completion.complete(null);
         } else {
           LOGGER.debug("Only {}/{} replicas scheduled for {}: {} in namespace: {} seconds so waiting...",
-              scale.getSpec().getReplicas(), count, getKind(), getName(), namespace);
+              specReplicas, count, getKind(), getName(), namespace);
         }
       } catch (KubernetesClientException e) {
         completion.completeExceptionally(e);

kubernetes-itests/src/test/java/io/fabric8/kubernetes/DeploymentIT.java

@@ -28,6 +28,7 @@
 import org.junit.jupiter.api.Test;
 
 import java.util.List;
+import java.util.Optional;
 import java.util.concurrent.TimeUnit;
 
 import static org.assertj.core.api.Assertions.assertThat;
@@ -78,6 +79,9 @@ void scale() {
     assertEquals(5, deployment1.getStatus().getReplicas());
     deployment1 = client.apps().deployments().withName("deployment-standard").scale(1, true);
     assertEquals(1, deployment1.getStatus().getReplicas());
+    // ensure scale to 0 as some replica fields can flip to null
+    deployment1 = client.apps().deployments().withName("deployment-standard").scale(0, true);
+    assertEquals(0, Optional.ofNullable(deployment1.getStatus().getReplicas()).orElse(0));
 
     // will only work on clusters older than 1.16
     if (client.supports(io.fabric8.kubernetes.api.model.extensions.Deployment.class)) {