Do not update number of replicas on no indices

server/src/main/java/org/elasticsearch/cluster/metadata/MetaData.java

@@ -1034,10 +1034,14 @@ public Builder updateSettings(Settings settings, String... indices) {
             return this;
         }
 
-        public Builder updateNumberOfReplicas(int numberOfReplicas, String... indices) {
-            if (indices == null || indices.length == 0) {
-                indices = this.indices.keys().toArray(String.class);
-            }
+        /**
+         * Update the number of replicas for the specified indices.
+         *
+         * @param numberOfReplicas the number of replicas
+         * @param indices          the indices to update the number of replicas for
+         * @return the builder
+         */
+        public Builder updateNumberOfReplicas(final int numberOfReplicas, final String[] indices) {
             for (String index : indices) {
                 IndexMetaData indexMetaData = this.indices.get(index);
                 if (indexMetaData == null) {

server/src/main/java/org/elasticsearch/cluster/routing/RoutingTable.java

@@ -457,13 +457,17 @@ public Builder updateNodes(long version, RoutingNodes routingNodes) {
             return this;
         }
 
-        public Builder updateNumberOfReplicas(int numberOfReplicas, String... indices) {
+        /**
+         * Update the number of replicas for the specified indices.
+         *
+         * @param numberOfReplicas the number of replicas
+         * @param indices          the indices to update the number of replicas for
+         * @return the builder
+         */
+        public Builder updateNumberOfReplicas(final int numberOfReplicas, final String[] indices) {
             if (indicesRouting == null) {
                 throw new IllegalStateException("once build is called the builder cannot be reused");
             }
-            if (indices == null || indices.length == 0) {
-                indices = indicesRouting.keys().toArray(String.class);
-            }
             for (String index : indices) {
                 IndexRoutingTable indexRoutingTable = indicesRouting.get(index);
                 if (indexRoutingTable == null) {

server/src/test/java/org/elasticsearch/cluster/routing/RoutingTableTests.java

@@ -275,7 +275,7 @@ public void testRoutingTableBuiltMoreThanOnce() {
             assertThat(e.getMessage(), containsString("cannot be reused"));
         }
         try {
-            b.updateNumberOfReplicas(1, "foo");
+            b.updateNumberOfReplicas(1, new String[]{"foo"});
             fail("expected exception");
         } catch (IllegalStateException e) {
             assertThat(e.getMessage(), containsString("cannot be reused"));

server/src/test/java/org/elasticsearch/cluster/routing/allocation/InSyncAllocationIdTests.java

@@ -292,8 +292,8 @@ public void testInSyncIdsNotTrimmedWhenNotGrowing() throws Exception {
 
         logger.info("decrease number of replicas to 0");
         clusterState = ClusterState.builder(clusterState)
-            .routingTable(RoutingTable.builder(clusterState.routingTable()).updateNumberOfReplicas(0, "test").build())
-            .metaData(MetaData.builder(clusterState.metaData()).updateNumberOfReplicas(0, "test")).build();
+            .routingTable(RoutingTable.builder(clusterState.routingTable()).updateNumberOfReplicas(0, new String[]{"test"}).build())
+            .metaData(MetaData.builder(clusterState.metaData()).updateNumberOfReplicas(0, new String[]{"test"})).build();
 
         logger.info("add back node 1");
         clusterState = ClusterState.builder(clusterState).nodes(DiscoveryNodes.builder().add(

server/src/test/java/org/elasticsearch/cluster/routing/allocation/PreferPrimaryAllocationTests.java

@@ -68,8 +68,10 @@ public void testPreferPrimaryAllocationOverReplicas() {
         }
 
         logger.info("increasing the number of replicas to 1, and perform a reroute (to get the replicas allocation going)");
-        RoutingTable updatedRoutingTable = RoutingTable.builder(clusterState.routingTable()).updateNumberOfReplicas(1).build();
-        metaData = MetaData.builder(clusterState.metaData()).updateNumberOfReplicas(1).build();
+        final String[] indices = {"test1", "test2"};
+        RoutingTable updatedRoutingTable =
+                RoutingTable.builder(clusterState.routingTable()).updateNumberOfReplicas(1, indices).build();
+        metaData = MetaData.builder(clusterState.metaData()).updateNumberOfReplicas(1, indices).build();
         clusterState = ClusterState.builder(clusterState).routingTable(updatedRoutingTable).metaData(metaData).build();
 
         clusterState = strategy.reroute(clusterState, "reroute");

server/src/test/java/org/elasticsearch/cluster/routing/allocation/UpdateNumberOfReplicasTests.java

@@ -96,8 +96,10 @@ public void testUpdateNumberOfReplicas() {
 
         logger.info("add another replica");
         routingNodes = clusterState.getRoutingNodes();
-        RoutingTable updatedRoutingTable = RoutingTable.builder(clusterState.routingTable()).updateNumberOfReplicas(2).build();
-        metaData = MetaData.builder(clusterState.metaData()).updateNumberOfReplicas(2).build();
+        final String[] indices = {"test"};
+        RoutingTable updatedRoutingTable =
+                RoutingTable.builder(clusterState.routingTable()).updateNumberOfReplicas(2, indices).build();
+        metaData = MetaData.builder(clusterState.metaData()).updateNumberOfReplicas(2, indices).build();
         clusterState = ClusterState.builder(clusterState).routingTable(updatedRoutingTable).metaData(metaData).build();
 
         assertThat(clusterState.metaData().index("test").getNumberOfReplicas(), equalTo(2));
@@ -143,8 +145,8 @@ public void testUpdateNumberOfReplicas() {
 
         logger.info("now remove a replica");
         routingNodes = clusterState.getRoutingNodes();
-        updatedRoutingTable = RoutingTable.builder(clusterState.routingTable()).updateNumberOfReplicas(1).build();
-        metaData = MetaData.builder(clusterState.metaData()).updateNumberOfReplicas(1).build();
+        updatedRoutingTable = RoutingTable.builder(clusterState.routingTable()).updateNumberOfReplicas(1, indices).build();
+        metaData = MetaData.builder(clusterState.metaData()).updateNumberOfReplicas(1, indices).build();
         clusterState = ClusterState.builder(clusterState).routingTable(updatedRoutingTable).metaData(metaData).build();
 
         assertThat(clusterState.metaData().index("test").getNumberOfReplicas(), equalTo(1));

server/src/test/java/org/elasticsearch/indices/settings/UpdateNumberOfReplicasIT.java

@@ -21,13 +21,15 @@
 
 import org.elasticsearch.action.admin.cluster.health.ClusterHealthResponse;
 import org.elasticsearch.action.search.SearchResponse;
+import org.elasticsearch.action.support.IndicesOptions;
 import org.elasticsearch.cluster.health.ClusterHealthStatus;
 import org.elasticsearch.cluster.metadata.IndexMetaData;
 import org.elasticsearch.common.Priority;
 import org.elasticsearch.common.settings.Settings;
 import org.elasticsearch.test.ESIntegTestCase;
 
 import java.io.IOException;
+import java.util.EnumSet;
 
 import static org.elasticsearch.common.xcontent.XContentFactory.jsonBuilder;
 import static org.elasticsearch.index.query.QueryBuilders.matchAllQuery;
@@ -274,4 +276,21 @@ public void testUpdateWithInvalidNumberOfReplicas() {
             assertEquals("Failed to parse value [" + value + "] for setting [index.number_of_replicas] must be >= 0", e.getMessage());
         }
     }
+
+    public void testUpdateNumberOfReplicasAllowNoIndices() {
+        createIndex("test-index", Settings.builder().put("index.number_of_replicas", 0).build());
+        final IndicesOptions options =
+                new IndicesOptions(EnumSet.of(IndicesOptions.Option.ALLOW_NO_INDICES), EnumSet.of(IndicesOptions.WildcardStates.OPEN));
+        assertAcked(client()
+                .admin()
+                .indices()
+                .prepareUpdateSettings("non-existent-*")
+                .setSettings(Settings.builder().put("index.number_of_replicas", 1))
+                .setIndicesOptions(options)
+                .get());
+        final int numberOfReplicas = Integer.parseInt(
+                client().admin().indices().prepareGetSettings("test-index").get().getSetting("test-index", "index.number_of_replicas"));
+        assertThat(numberOfReplicas, equalTo(0));
+    }
+
 }