Restore process should replace the mapping and settings if index already exists

Closes #5210

src/main/java/org/elasticsearch/snapshots/RestoreService.java

@@ -191,7 +191,8 @@ public class RestoreService extends AbstractComponent implements ClusterStateLis
                                             "] shard from snapshot with [" + snapshotIndexMetaData.getNumberOfShards() + "] shards");
                                 }
                                 // Index exists and it's closed - open it in metadata and start recovery
-                                IndexMetaData.Builder indexMdBuilder = IndexMetaData.builder(currentIndexMetaData).state(IndexMetaData.State.OPEN);
+                                IndexMetaData.Builder indexMdBuilder = IndexMetaData.builder(snapshotIndexMetaData).state(IndexMetaData.State.OPEN);
+                                indexMdBuilder.version(Math.max(snapshotIndexMetaData.version(), currentIndexMetaData.version() + 1));
                                 IndexMetaData updatedIndexMetaData = indexMdBuilder.index(renamedIndex).build();
                                 rtBuilder.addAsRestore(updatedIndexMetaData, restoreSource);
                                 blocks.removeIndexBlock(index, INDEX_CLOSED_BLOCK);

src/test/java/org/elasticsearch/snapshots/SharedClusterSnapshotRestoreTests.java

@@ -29,12 +29,15 @@ import org.elasticsearch.action.admin.cluster.snapshots.delete.DeleteSnapshotRes
 import org.elasticsearch.action.admin.cluster.snapshots.get.GetSnapshotsResponse;
 import org.elasticsearch.action.admin.cluster.snapshots.restore.RestoreSnapshotResponse;
 import org.elasticsearch.action.admin.cluster.state.ClusterStateResponse;
+import org.elasticsearch.action.admin.indices.settings.get.GetSettingsResponse;
 import org.elasticsearch.action.count.CountResponse;
 import org.elasticsearch.client.Client;
 import org.elasticsearch.cluster.ClusterState;
 import org.elasticsearch.cluster.metadata.IndexMetaData;
+import org.elasticsearch.cluster.metadata.MappingMetaData;
 import org.elasticsearch.cluster.routing.allocation.decider.FilterAllocationDecider;
 import org.elasticsearch.common.Strings;
+import org.elasticsearch.common.collect.ImmutableOpenMap;
 import org.elasticsearch.common.settings.ImmutableSettings;
 import org.elasticsearch.common.settings.Settings;
 import org.elasticsearch.common.unit.TimeValue;
@@ -138,6 +141,54 @@ public class SharedClusterSnapshotRestoreTests extends AbstractSnapshotTests {
         assertThat(clusterState.getMetaData().hasIndex("test-idx-2"), equalTo(false));
     }
 
+    @Test
+    public void restoreWithDifferentMappingsAndSettingsTest() throws Exception {
+        Client client = client();
+
+        logger.info("-->  creating repository");
+        PutRepositoryResponse putRepositoryResponse = client.admin().cluster().preparePutRepository("test-repo")
+                .setType("fs").setSettings(ImmutableSettings.settingsBuilder()
+                        .put("location", newTempDir(LifecycleScope.SUITE))
+                        .put("compress", randomBoolean())
+                        .put("chunk_size", randomIntBetween(100, 1000))
+                ).get();
+        assertThat(putRepositoryResponse.isAcknowledged(), equalTo(true));
+
+        logger.info("--> create index with foo type");
+        assertAcked(prepareCreate("test-idx", 2, ImmutableSettings.builder().put("refresh_interval", 10)));
+
+        assertAcked(client().admin().indices().preparePutMapping("test-idx").setType("foo").setSource("baz", "type=string"));
+        ensureGreen();
+
+        logger.info("--> snapshot it");
+        CreateSnapshotResponse createSnapshotResponse = client.admin().cluster().prepareCreateSnapshot("test-repo", "test-snap").setWaitForCompletion(true).setIndices("test-idx").get();
+        assertThat(createSnapshotResponse.getSnapshotInfo().successfulShards(), greaterThan(0));
+        assertThat(createSnapshotResponse.getSnapshotInfo().successfulShards(), equalTo(createSnapshotResponse.getSnapshotInfo().totalShards()));
+
+        logger.info("--> delete the index and recreate it with bar type");
+        wipeIndices("test-idx");
+        assertAcked(prepareCreate("test-idx", 2, ImmutableSettings.builder().put("refresh_interval", 5)));
+        assertAcked(client().admin().indices().preparePutMapping("test-idx").setType("bar").setSource("baz", "type=string"));
+        ensureGreen();
+
+        logger.info("--> close index");
+        client.admin().indices().prepareClose("test-idx").get();
+
+        logger.info("--> restore all indices from the snapshot");
+        RestoreSnapshotResponse restoreSnapshotResponse = client.admin().cluster().prepareRestoreSnapshot("test-repo", "test-snap").setWaitForCompletion(true).execute().actionGet();
+        assertThat(restoreSnapshotResponse.getRestoreInfo().totalShards(), greaterThan(0));
+        ensureGreen();
+
+        logger.info("--> assert that old mapping is restored");
+        ImmutableOpenMap<String, MappingMetaData> mappings = client().admin().cluster().prepareState().get().getState().getMetaData().getIndices().get("test-idx").getMappings();
+        assertThat(mappings.get("foo"), notNullValue());
+        assertThat(mappings.get("bar"), nullValue());
+
+        logger.info("--> assert that old settings are restored");
+        GetSettingsResponse getSettingsResponse = client.admin().indices().prepareGetSettings("test-idx").execute().actionGet();
+        assertThat(getSettingsResponse.getSetting("test-idx", "index.refresh_interval"), equalTo("10"));
+    }
+
     @Test
     public void emptySnapshotTest() throws Exception {
         Client client = client();