Move GatewayShardsState logic into IndexShard

src/main/java/org/elasticsearch/cluster/routing/ImmutableShardRouting.java

@@ -301,19 +301,21 @@ public boolean equals(Object o) {
         if (shardId != that.shardId) {
             return false;
         }
-        if (currentNodeId != null ? !currentNodeId.equals(that.currentNodeId) : that.currentNodeId != null)
+        if (currentNodeId != null ? !currentNodeId.equals(that.currentNodeId) : that.currentNodeId != null) {
             return false;
+        }
         if (index != null ? !index.equals(that.index) : that.index != null) {
             return false;
         }
-        if (relocatingNodeId != null ? !relocatingNodeId.equals(that.relocatingNodeId) : that.relocatingNodeId != null)
+        if (relocatingNodeId != null ? !relocatingNodeId.equals(that.relocatingNodeId) : that.relocatingNodeId != null) {
             return false;
+        }
         if (state != that.state) {
             return false;
         }
-        if (restoreSource != null ? !restoreSource.equals(that.restoreSource) : that.restoreSource != null)
+        if (restoreSource != null ? !restoreSource.equals(that.restoreSource) : that.restoreSource != null) {
             return false;
-
+        }
         return true;
     }
 

src/main/java/org/elasticsearch/gateway/Gateway.java

@@ -31,6 +31,7 @@
 import org.elasticsearch.common.inject.Inject;
 import org.elasticsearch.common.settings.Settings;
 import org.elasticsearch.env.NodeEnvironment;
+import org.elasticsearch.indices.IndicesService;
 
 import java.nio.file.Path;
 
@@ -43,7 +44,6 @@ public class Gateway extends AbstractComponent implements ClusterStateListener {
 
     private final NodeEnvironment nodeEnv;
 
-    private final GatewayShardsState shardsState;
     private final GatewayMetaState metaState;
 
     private final TransportNodesListGatewayMetaState listGatewayMetaState;
@@ -52,8 +52,7 @@ public class Gateway extends AbstractComponent implements ClusterStateListener {
     private final ClusterName clusterName;
 
     @Inject
-    public Gateway(Settings settings, ClusterService clusterService, NodeEnvironment nodeEnv,
-                   GatewayShardsState shardsState, GatewayMetaState metaState,
+    public Gateway(Settings settings, ClusterService clusterService, NodeEnvironment nodeEnv, GatewayMetaState metaState,
                    TransportNodesListGatewayMetaState listGatewayMetaState, ClusterName clusterName) {
         super(settings);
         this.clusterService = clusterService;
@@ -62,8 +61,6 @@ public Gateway(Settings settings, ClusterService clusterService, NodeEnvironment
         this.listGatewayMetaState = listGatewayMetaState;
         this.clusterName = clusterName;
 
-        this.shardsState = shardsState;
-
         clusterService.addLast(this);
 
         // we define what is our minimum "master" nodes, use that to allow for recovery
@@ -180,7 +177,6 @@ public void clusterChanged(final ClusterChangedEvent event) {
         // order is important, first metaState, and then shardsState
         // so dangling indices will be recorded
         metaState.clusterChanged(event);
-        shardsState.clusterChanged(event);
     }
 
     public interface GatewayStateRecoveredListener {

src/main/java/org/elasticsearch/gateway/GatewayMetaState.java

@@ -37,6 +37,7 @@
 import org.elasticsearch.common.settings.ImmutableSettings;
 import org.elasticsearch.common.settings.Settings;
 import org.elasticsearch.common.unit.TimeValue;
+import org.elasticsearch.discovery.Discovery;
 import org.elasticsearch.env.NodeEnvironment;
 
 import java.io.IOException;
@@ -68,6 +69,9 @@ public GatewayMetaState(Settings settings, NodeEnvironment nodeEnv, MetaStateSer
         this.danglingIndicesState = danglingIndicesState;
         nodesListGatewayMetaState.init(this);
 
+        if (DiscoveryNode.dataNode(settings)) {
+            ensureNoPre019ShardState(nodeEnv);
+        }
 
         if (DiscoveryNode.masterNode(settings) || DiscoveryNode.dataNode(settings)) {
             nodeEnv.ensureAtomicMoveSupported();
@@ -230,4 +234,21 @@ private void pre20Upgrade() throws Exception {
                     + "used some custom routing logic, you can now remove these settings from your `elasticsearch.yml` file", DEPRECATED_SETTING_ROUTING_HASH_FUNCTION, DEPRECATED_SETTING_ROUTING_USE_TYPE);
         }
     }
+
+
+    // shard state BWC
+    private void ensureNoPre019ShardState(NodeEnvironment nodeEnv) throws Exception {
+        for (Path dataLocation : nodeEnv.nodeDataPaths()) {
+            final Path stateLocation = dataLocation.resolve(MetaDataStateFormat.STATE_DIR_NAME);
+            if (Files.exists(stateLocation)) {
+                try (DirectoryStream<Path> stream = Files.newDirectoryStream(stateLocation, "shards-*")) {
+                    for (Path stateFile : stream) {
+                        throw new ElasticsearchIllegalStateException("Detected pre 0.19 shard state file please upgrade to a version before "
+                                + Version.CURRENT.minimumCompatibilityVersion()
+                                + " first to upgrade state structures - shard state found: [" + stateFile.getParent().toAbsolutePath());
+                    }
+                }
+            }
+        }
+    }
 }

src/main/java/org/elasticsearch/gateway/GatewayModule.java

@@ -32,7 +32,6 @@ protected void configure() {
         bind(DanglingIndicesState.class).asEagerSingleton();
         bind(GatewayService.class).asEagerSingleton();
         bind(Gateway.class).asEagerSingleton();
-        bind(GatewayShardsState.class).asEagerSingleton();
         bind(TransportNodesListGatewayMetaState.class).asEagerSingleton();
         bind(GatewayMetaState.class).asEagerSingleton();
         bind(TransportNodesListGatewayStartedShards.class).asEagerSingleton();