Fix AnalyticsStats response serialization

Fixes incorrect serialization of cumulativeCardinalityUsage

Relates to elastic#55162

Author: imotov

x-pack/plugin/analytics/src/test/java/org/elasticsearch/xpack/analytics/action/AnalyticsStatsActionNodeResponseTests.java

@@ -0,0 +1,29 @@
+/*
+ * Copyright Elasticsearch B.V. and/or licensed to Elasticsearch B.V. under one
+ * or more contributor license agreements. Licensed under the Elastic License;
+ * you may not use this file except in compliance with the Elastic License.
+ */
+
+package org.elasticsearch.xpack.analytics.action;
+
+import org.elasticsearch.Version;
+import org.elasticsearch.cluster.node.DiscoveryNode;
+import org.elasticsearch.common.io.stream.Writeable;
+import org.elasticsearch.test.AbstractWireSerializingTestCase;
+import org.elasticsearch.xpack.core.analytics.action.AnalyticsStatsAction;
+
+public class AnalyticsStatsActionNodeResponseTests extends AbstractWireSerializingTestCase<AnalyticsStatsAction.NodeResponse> {
+
+    @Override
+    protected Writeable.Reader<AnalyticsStatsAction.NodeResponse> instanceReader() {
+        return AnalyticsStatsAction.NodeResponse::new;
+    }
+
+    @Override
+    protected AnalyticsStatsAction.NodeResponse createTestInstance() {
+        String nodeName = randomAlphaOfLength(10);
+        DiscoveryNode node = new DiscoveryNode(nodeName, buildNewFakeTransportAddress(), Version.CURRENT);
+        return new AnalyticsStatsAction.NodeResponse(node, randomLongBetween(0, 1000), randomLongBetween(0, 1000),
+            randomLongBetween(0, 1000), randomLongBetween(0, 1000));
+    }
+}

x-pack/plugin/core/src/main/java/org/elasticsearch/xpack/core/analytics/action/AnalyticsStatsAction.java

@@ -152,7 +152,7 @@ public void writeTo(StreamOutput out) throws IOException {
             if (out.getVersion().onOrAfter(Version.V_7_7_0)) {
                 out.writeVLong(boxplotUsage);
             }
-            out.writeVLong(cumulativeCardinalityUsage);
+            out.writeZLong(cumulativeCardinalityUsage);
             if (out.getVersion().onOrAfter(Version.V_7_7_0)) {
                 out.writeVLong(stringStatsUsage);
                 out.writeVLong(topMetricsUsage);
@@ -185,5 +185,21 @@ public long getStringStatsUsage() {
         public long getTopMetricsUsage() {
             return topMetricsUsage;
         }
+
+        @Override
+        public boolean equals(Object o) {
+            if (this == o) return true;
+            if (o == null || getClass() != o.getClass()) return false;
+            NodeResponse that = (NodeResponse) o;
+            return boxplotUsage == that.boxplotUsage &&
+                cumulativeCardinalityUsage == that.cumulativeCardinalityUsage &&
+                stringStatsUsage == that.stringStatsUsage &&
+                topMetricsUsage == that.topMetricsUsage;
+        }
+
+        @Override
+        public int hashCode() {
+            return Objects.hash(boxplotUsage, cumulativeCardinalityUsage, stringStatsUsage, topMetricsUsage);
+        }
     }
 }