Remove GroupShardsIterator and replace it with plain List

server/src/internalClusterTest/java/org/elasticsearch/index/shard/RemoveCorruptedShardDataCommandIT.java

@@ -32,7 +32,6 @@
 import org.elasticsearch.cluster.ClusterState;
 import org.elasticsearch.cluster.node.DiscoveryNode;
 import org.elasticsearch.cluster.node.DiscoveryNodes;
-import org.elasticsearch.cluster.routing.GroupShardsIterator;
 import org.elasticsearch.cluster.routing.ShardIterator;
 import org.elasticsearch.cluster.routing.ShardRouting;
 import org.elasticsearch.cluster.routing.ShardRoutingState;
@@ -531,8 +530,7 @@ public void testResolvePath() throws Exception {
             nodeNameToNodeId.put(cursor.getValue().getName(), cursor.getKey());
         }
 
-        final GroupShardsIterator<ShardIterator> shardIterators = state.getRoutingTable()
-            .activePrimaryShardsGrouped(new String[] { indexName }, false);
+        final List<ShardIterator> shardIterators = state.getRoutingTable().activePrimaryShardsGrouped(new String[] { indexName }, false);
         final List<ShardIterator> iterators = iterableAsArrayList(shardIterators);
         final ShardRouting shardRouting = iterators.iterator().next().nextOrNull();
         assertThat(shardRouting, notNullValue());
@@ -571,8 +569,7 @@ public void testResolvePath() throws Exception {
 
     private Path getPathToShardData(String indexName, String dirSuffix) {
         ClusterState state = clusterAdmin().prepareState(TEST_REQUEST_TIMEOUT).get().getState();
-        GroupShardsIterator<ShardIterator> shardIterators = state.getRoutingTable()
-            .activePrimaryShardsGrouped(new String[] { indexName }, false);
+        List<ShardIterator> shardIterators = state.getRoutingTable().activePrimaryShardsGrouped(new String[] { indexName }, false);
         List<ShardIterator> iterators = iterableAsArrayList(shardIterators);
         ShardIterator shardIterator = RandomPicks.randomFrom(random(), iterators);
         ShardRouting shardRouting = shardIterator.nextOrNull();

server/src/internalClusterTest/java/org/elasticsearch/index/store/CorruptedFileIT.java

@@ -34,7 +34,6 @@
 import org.elasticsearch.cluster.health.ClusterHealthStatus;
 import org.elasticsearch.cluster.metadata.IndexMetadata;
 import org.elasticsearch.cluster.node.DiscoveryNode;
-import org.elasticsearch.cluster.routing.GroupShardsIterator;
 import org.elasticsearch.cluster.routing.IndexShardRoutingTable;
 import org.elasticsearch.cluster.routing.ShardIterator;
 import org.elasticsearch.cluster.routing.ShardRouting;
@@ -311,8 +310,7 @@ public void testCorruptPrimaryNoReplica() throws ExecutionException, Interrupted
         }
         assertThat(response.getStatus(), is(ClusterHealthStatus.RED));
         ClusterState state = clusterAdmin().prepareState(TEST_REQUEST_TIMEOUT).get().getState();
-        GroupShardsIterator<ShardIterator> shardIterators = state.getRoutingTable()
-            .activePrimaryShardsGrouped(new String[] { "test" }, false);
+        List<ShardIterator> shardIterators = state.getRoutingTable().activePrimaryShardsGrouped(new String[] { "test" }, false);
         for (ShardIterator iterator : shardIterators) {
             ShardRouting routing;
             while ((routing = iterator.nextOrNull()) != null) {
@@ -667,7 +665,7 @@ public void testReplicaCorruption() throws Exception {
 
     private int numShards(String... index) {
         ClusterState state = clusterAdmin().prepareState(TEST_REQUEST_TIMEOUT).get().getState();
-        GroupShardsIterator<?> shardIterators = state.getRoutingTable().activePrimaryShardsGrouped(index, false);
+        List<?> shardIterators = state.getRoutingTable().activePrimaryShardsGrouped(index, false);
         return shardIterators.size();
     }
 
@@ -695,8 +693,7 @@ private ShardRouting corruptRandomPrimaryFile() throws IOException {
     private ShardRouting corruptRandomPrimaryFile(final boolean includePerCommitFiles) throws IOException {
         ClusterState state = clusterAdmin().prepareState(TEST_REQUEST_TIMEOUT).get().getState();
         Index test = state.metadata().index("test").getIndex();
-        GroupShardsIterator<ShardIterator> shardIterators = state.getRoutingTable()
-            .activePrimaryShardsGrouped(new String[] { "test" }, false);
+        List<ShardIterator> shardIterators = state.getRoutingTable().activePrimaryShardsGrouped(new String[] { "test" }, false);
         List<ShardIterator> iterators = iterableAsArrayList(shardIterators);
         ShardIterator shardIterator = RandomPicks.randomFrom(random(), iterators);
         ShardRouting shardRouting = shardIterator.nextOrNull();

server/src/internalClusterTest/java/org/elasticsearch/index/suggest/stats/SuggestStatsIT.java

@@ -14,7 +14,6 @@
 import org.elasticsearch.action.admin.indices.stats.IndicesStatsResponse;
 import org.elasticsearch.action.search.SearchRequestBuilder;
 import org.elasticsearch.cluster.ClusterState;
-import org.elasticsearch.cluster.routing.GroupShardsIterator;
 import org.elasticsearch.cluster.routing.ShardIterator;
 import org.elasticsearch.cluster.routing.ShardRouting;
 import org.elasticsearch.index.search.stats.SearchStats;
@@ -24,6 +23,7 @@
 import org.elasticsearch.test.ESIntegTestCase;
 
 import java.util.HashSet;
+import java.util.List;
 import java.util.Set;
 
 import static org.elasticsearch.test.hamcrest.ElasticsearchAssertions.assertAcked;
@@ -146,7 +146,7 @@ private SearchRequestBuilder addSuggestions(SearchRequestBuilder request, int i)
 
     private Set<String> nodeIdsWithIndex(String... indices) {
         ClusterState state = clusterAdmin().prepareState(TEST_REQUEST_TIMEOUT).get().getState();
-        GroupShardsIterator<ShardIterator> allAssignedShardsGrouped = state.routingTable().allAssignedShardsGrouped(indices, true);
+        List<ShardIterator> allAssignedShardsGrouped = state.routingTable().allAssignedShardsGrouped(indices, true);
         Set<String> nodes = new HashSet<>();
         for (ShardIterator shardIterator : allAssignedShardsGrouped) {
             for (ShardRouting routing : shardIterator) {
@@ -161,7 +161,7 @@ private Set<String> nodeIdsWithIndex(String... indices) {
 
     protected int numAssignedShards(String... indices) {
         ClusterState state = clusterAdmin().prepareState(TEST_REQUEST_TIMEOUT).get().getState();
-        GroupShardsIterator<?> allAssignedShardsGrouped = state.routingTable().allAssignedShardsGrouped(indices, true);
+        List<?> allAssignedShardsGrouped = state.routingTable().allAssignedShardsGrouped(indices, true);
         return allAssignedShardsGrouped.size();
     }
 }

server/src/internalClusterTest/java/org/elasticsearch/search/stats/SearchStatsIT.java

@@ -14,7 +14,6 @@
 import org.elasticsearch.action.admin.indices.stats.IndicesStatsResponse;
 import org.elasticsearch.cluster.ClusterState;
 import org.elasticsearch.cluster.metadata.IndexMetadata;
-import org.elasticsearch.cluster.routing.GroupShardsIterator;
 import org.elasticsearch.cluster.routing.ShardIterator;
 import org.elasticsearch.cluster.routing.ShardRouting;
 import org.elasticsearch.common.settings.Settings;
@@ -165,7 +164,7 @@ public void testSimpleStats() throws Exception {
 
     private Set<String> nodeIdsWithIndex(String... indices) {
         ClusterState state = clusterAdmin().prepareState(TEST_REQUEST_TIMEOUT).get().getState();
-        GroupShardsIterator<ShardIterator> allAssignedShardsGrouped = state.routingTable().allAssignedShardsGrouped(indices, true);
+        List<ShardIterator> allAssignedShardsGrouped = state.routingTable().allAssignedShardsGrouped(indices, true);
         Set<String> nodes = new HashSet<>();
         for (ShardIterator shardIterator : allAssignedShardsGrouped) {
             for (ShardRouting routing : shardIterator) {
@@ -248,7 +247,7 @@ public void testOpenContexts() {
 
     protected int numAssignedShards(String... indices) {
         ClusterState state = clusterAdmin().prepareState(TEST_REQUEST_TIMEOUT).get().getState();
-        GroupShardsIterator<?> allAssignedShardsGrouped = state.routingTable().allAssignedShardsGrouped(indices, true);
+        List<?> allAssignedShardsGrouped = state.routingTable().allAssignedShardsGrouped(indices, true);
         return allAssignedShardsGrouped.size();
     }
 

server/src/main/java/org/elasticsearch/action/admin/cluster/shards/TransportClusterSearchShardsAction.java

@@ -19,7 +19,6 @@
 import org.elasticsearch.cluster.metadata.IndexNameExpressionResolver;
 import org.elasticsearch.cluster.metadata.IndexNameExpressionResolver.ResolvedExpression;
 import org.elasticsearch.cluster.node.DiscoveryNode;
-import org.elasticsearch.cluster.routing.GroupShardsIterator;
 import org.elasticsearch.cluster.routing.ShardIterator;
 import org.elasticsearch.cluster.routing.ShardRouting;
 import org.elasticsearch.cluster.service.ClusterService;
@@ -34,6 +33,7 @@
 
 import java.util.HashMap;
 import java.util.HashSet;
+import java.util.List;
 import java.util.Map;
 import java.util.Set;
 
@@ -101,7 +101,7 @@ protected void masterOperation(
         }
 
         Set<String> nodeIds = new HashSet<>();
-        GroupShardsIterator<ShardIterator> groupShardsIterator = clusterService.operationRouting()
+        List<ShardIterator> groupShardsIterator = clusterService.operationRouting()
             .searchShards(clusterState, concreteIndices, routingMap, request.preference());
         ShardRouting shard;
         ClusterSearchShardsGroup[] groupResponses = new ClusterSearchShardsGroup[groupShardsIterator.size()];

server/src/main/java/org/elasticsearch/action/admin/indices/diskusage/TransportAnalyzeIndexDiskUsageAction.java

@@ -21,7 +21,6 @@
 import org.elasticsearch.cluster.block.ClusterBlockLevel;
 import org.elasticsearch.cluster.metadata.IndexNameExpressionResolver;
 import org.elasticsearch.cluster.node.DiscoveryNode;
-import org.elasticsearch.cluster.routing.GroupShardsIterator;
 import org.elasticsearch.cluster.routing.ShardIterator;
 import org.elasticsearch.cluster.routing.ShardRouting;
 import org.elasticsearch.cluster.service.ClusterService;
@@ -214,13 +213,8 @@ protected AnalyzeIndexDiskUsageResponse newResponse(
     }
 
     @Override
-    protected GroupShardsIterator<ShardIterator> shards(
-        ClusterState clusterState,
-        AnalyzeIndexDiskUsageRequest request,
-        String[] concreteIndices
-    ) {
-        final GroupShardsIterator<ShardIterator> groups = clusterService.operationRouting()
-            .searchShards(clusterState, concreteIndices, null, null);
+    protected List<ShardIterator> shards(ClusterState clusterState, AnalyzeIndexDiskUsageRequest request, String[] concreteIndices) {
+        final List<ShardIterator> groups = clusterService.operationRouting().searchShards(clusterState, concreteIndices, null, null);
         for (ShardIterator group : groups) {
             // fails fast if any non-active groups
             if (group.size() == 0) {

server/src/main/java/org/elasticsearch/action/admin/indices/validate/query/TransportValidateQueryAction.java

@@ -22,7 +22,6 @@
 import org.elasticsearch.cluster.block.ClusterBlockLevel;
 import org.elasticsearch.cluster.metadata.IndexNameExpressionResolver;
 import org.elasticsearch.cluster.metadata.IndexNameExpressionResolver.ResolvedExpression;
-import org.elasticsearch.cluster.routing.GroupShardsIterator;
 import org.elasticsearch.cluster.routing.ShardIterator;
 import org.elasticsearch.cluster.routing.ShardRouting;
 import org.elasticsearch.cluster.service.ClusterService;
@@ -145,7 +144,7 @@ protected ShardValidateQueryResponse readShardResponse(StreamInput in) throws IO
     }
 
     @Override
-    protected GroupShardsIterator<ShardIterator> shards(ClusterState clusterState, ValidateQueryRequest request, String[] concreteIndices) {
+    protected List<ShardIterator> shards(ClusterState clusterState, ValidateQueryRequest request, String[] concreteIndices) {
         final String routing;
         if (request.allShards()) {
             routing = null;

server/src/main/java/org/elasticsearch/action/fieldcaps/RequestDispatcher.java

@@ -18,7 +18,6 @@
 import org.elasticsearch.action.OriginalIndices;
 import org.elasticsearch.cluster.ClusterState;
 import org.elasticsearch.cluster.node.DiscoveryNode;
-import org.elasticsearch.cluster.routing.GroupShardsIterator;
 import org.elasticsearch.cluster.routing.ShardIterator;
 import org.elasticsearch.cluster.routing.ShardRouting;
 import org.elasticsearch.cluster.service.ClusterService;
@@ -93,7 +92,7 @@ final class RequestDispatcher {
         this.onComplete = new RunOnce(onComplete);
         this.indexSelectors = ConcurrentCollections.newConcurrentMap();
         for (String index : indices) {
-            final GroupShardsIterator<ShardIterator> shardIts;
+            final List<ShardIterator> shardIts;
             try {
                 shardIts = clusterService.operationRouting().searchShards(clusterState, new String[] { index }, null, null);
             } catch (Exception e) {
@@ -250,7 +249,7 @@ private static class IndexSelector {
         private final Set<ShardId> unmatchedShardIds = new HashSet<>();
         private final Map<ShardId, Exception> failures = new HashMap<>();
 
-        IndexSelector(GroupShardsIterator<ShardIterator> shardIts) {
+        IndexSelector(List<ShardIterator> shardIts) {
             for (ShardIterator shardIt : shardIts) {
                 for (ShardRouting shard : shardIt) {
                     nodeToShards.computeIfAbsent(shard.currentNodeId(), node -> new ArrayList<>()).add(shard);

server/src/main/java/org/elasticsearch/action/search/AbstractSearchAsyncAction.java

@@ -22,7 +22,6 @@
 import org.elasticsearch.action.support.SubscribableListener;
 import org.elasticsearch.action.support.TransportActions;
 import org.elasticsearch.cluster.ClusterState;
-import org.elasticsearch.cluster.routing.GroupShardsIterator;
 import org.elasticsearch.common.bytes.BytesReference;
 import org.elasticsearch.common.io.stream.NamedWriteableRegistry;
 import org.elasticsearch.common.util.Maps;
@@ -60,9 +59,9 @@
 import static org.elasticsearch.core.Strings.format;
 
 /**
- * This is an abstract base class that encapsulates the logic to fan out to all shards in provided {@link GroupShardsIterator}
+ * This is an abstract base class that encapsulates the logic to fan out to all shards in provided {@link List<SearchShardIterator>}
  * and collect the results. If a shard request returns a failure this class handles the advance to the next replica of the shard until
- * the shards replica iterator is exhausted. Each shard is referenced by position in the {@link GroupShardsIterator} which is later
+ * the shards replica iterator is exhausted. Each shard is referenced by position in the {@link List<SearchShardIterator>} which is later
  * referred to as the {@code shardIndex}.
  * The fan out and collect algorithm is traditionally used as the initial phase which can either be a query execution or collection of
  * distributed frequencies
@@ -93,8 +92,8 @@ abstract class AbstractSearchAsyncAction<Result extends SearchPhaseResult> exten
     private final SearchTimeProvider timeProvider;
     private final SearchResponse.Clusters clusters;
 
-    protected final GroupShardsIterator<SearchShardIterator> toSkipShardsIts;
-    protected final GroupShardsIterator<SearchShardIterator> shardsIts;
+    protected final List<SearchShardIterator> toSkipShardsIts;
+    protected final List<SearchShardIterator> shardsIts;
     private final SearchShardIterator[] shardIterators;
     private final AtomicInteger outstandingShards;
     private final int maxConcurrentRequestsPerNode;
@@ -116,7 +115,7 @@ abstract class AbstractSearchAsyncAction<Result extends SearchPhaseResult> exten
         Executor executor,
         SearchRequest request,
         ActionListener<SearchResponse> listener,
-        GroupShardsIterator<SearchShardIterator> shardsIts,
+        List<SearchShardIterator> shardsIts,
         SearchTimeProvider timeProvider,
         ClusterState clusterState,
         SearchTask task,
@@ -135,8 +134,8 @@ abstract class AbstractSearchAsyncAction<Result extends SearchPhaseResult> exten
                 iterators.add(iterator);
             }
         }
-        this.toSkipShardsIts = new GroupShardsIterator<>(toSkipIterators);
-        this.shardsIts = new GroupShardsIterator<>(iterators);
+        this.toSkipShardsIts = toSkipIterators;
+        this.shardsIts = iterators;
         outstandingShards = new AtomicInteger(shardsIts.size());
         this.shardIterators = iterators.toArray(new SearchShardIterator[0]);
         // we later compute the shard index based on the natural order of the shards
@@ -171,8 +170,8 @@ protected void notifyListShards(
         SearchSourceBuilder sourceBuilder
     ) {
         progressListener.notifyListShards(
-            SearchProgressListener.buildSearchShards(this.shardsIts),
-            SearchProgressListener.buildSearchShards(toSkipShardsIts),
+            SearchProgressListener.buildSearchShardsFromIter(this.shardsIts),
+            SearchProgressListener.buildSearchShardsFromIter(toSkipShardsIts),
             clusters,
             sourceBuilder == null || sourceBuilder.size() > 0,
             timeProvider