Remove some uses of V_8_0_0 constant from server (elastic#135738)

Since main (9.2) is only compatible back to 8.19 nodes, serialization
logic checking for pre 8.19 isnot necessary. This commit removes
some of that logic for the 8.0.0 constant from server.

Author: rjernst

server/src/main/java/org/elasticsearch/action/DocWriteResponse.java

@@ -8,7 +8,6 @@
  */
 package org.elasticsearch.action;
 
-import org.elasticsearch.TransportVersions;
 import org.elasticsearch.action.bulk.IndexDocFailureStoreStatus;
 import org.elasticsearch.action.support.WriteRequest;
 import org.elasticsearch.action.support.WriteRequest.RefreshPolicy;
@@ -115,10 +114,6 @@ public DocWriteResponse(ShardId shardId, String id, long seqNo, long primaryTerm
     protected DocWriteResponse(ShardId shardId, StreamInput in) throws IOException {
         super(in);
         this.shardId = shardId;
-        if (in.getTransportVersion().before(TransportVersions.V_8_0_0)) {
-            String type = in.readString();
-            assert MapperService.SINGLE_MAPPING_NAME.equals(type) : "Expected [_doc] but received [" + type + "]";
-        }
         id = in.readString();
         version = in.readZLong();
         seqNo = in.readZLong();
@@ -134,10 +129,6 @@ protected DocWriteResponse(ShardId shardId, StreamInput in) throws IOException {
     protected DocWriteResponse(StreamInput in) throws IOException {
         super(in);
         shardId = new ShardId(in);
-        if (in.getTransportVersion().before(TransportVersions.V_8_0_0)) {
-            String type = in.readString();
-            assert MapperService.SINGLE_MAPPING_NAME.equals(type) : "Expected [_doc] but received [" + type + "]";
-        }
         id = in.readString();
         version = in.readZLong();
         seqNo = in.readZLong();
@@ -266,9 +257,6 @@ public void writeTo(StreamOutput out) throws IOException {
     }
 
     private void writeWithoutShardId(StreamOutput out) throws IOException {
-        if (out.getTransportVersion().before(TransportVersions.V_8_0_0)) {
-            out.writeString(MapperService.SINGLE_MAPPING_NAME);
-        }
         out.writeString(id);
         out.writeZLong(version);
         out.writeZLong(seqNo);

server/src/main/java/org/elasticsearch/action/admin/cluster/configuration/AddVotingConfigExclusionsRequest.java

@@ -8,7 +8,6 @@
  */
 package org.elasticsearch.action.admin.cluster.configuration;
 
-import org.elasticsearch.TransportVersions;
 import org.elasticsearch.action.ActionRequestValidationException;
 import org.elasticsearch.action.support.master.MasterNodeRequest;
 import org.elasticsearch.cluster.ClusterState;
@@ -78,12 +77,6 @@ public AddVotingConfigExclusionsRequest(TimeValue masterNodeTimeout, String[] no
 
     public AddVotingConfigExclusionsRequest(StreamInput in) throws IOException {
         super(in);
-        if (in.getTransportVersion().before(TransportVersions.V_8_0_0)) {
-            final String[] legacyNodeDescriptions = in.readStringArray();
-            if (legacyNodeDescriptions.length > 0) {
-                throw new IllegalArgumentException("legacy [node_name] field was deprecated and must be empty");
-            }
-        }
         nodeIds = in.readStringArray();
         nodeNames = in.readStringArray();
         timeout = in.readTimeValue();
@@ -191,9 +184,6 @@ public ActionRequestValidationException validate() {
     @Override
     public void writeTo(StreamOutput out) throws IOException {
         super.writeTo(out);
-        if (out.getTransportVersion().before(TransportVersions.V_8_0_0)) {
-            out.writeStringArray(Strings.EMPTY_ARRAY);
-        }
         out.writeStringArray(nodeIds);
         out.writeStringArray(nodeNames);
         out.writeTimeValue(timeout);

server/src/main/java/org/elasticsearch/action/admin/cluster/snapshots/create/CreateSnapshotRequest.java

@@ -10,7 +10,6 @@
 package org.elasticsearch.action.admin.cluster.snapshots.create;
 
 import org.elasticsearch.ElasticsearchException;
-import org.elasticsearch.TransportVersion;
 import org.elasticsearch.TransportVersions;
 import org.elasticsearch.action.ActionRequestValidationException;
 import org.elasticsearch.action.IndicesRequest;
@@ -21,7 +20,6 @@
 import org.elasticsearch.common.bytes.BytesReference;
 import org.elasticsearch.common.io.stream.StreamInput;
 import org.elasticsearch.common.io.stream.StreamOutput;
-import org.elasticsearch.common.settings.Settings;
 import org.elasticsearch.core.Nullable;
 import org.elasticsearch.core.TimeValue;
 import org.elasticsearch.xcontent.ToXContentObject;
@@ -36,7 +34,6 @@
 
 import static org.elasticsearch.action.ValidateActions.addValidationError;
 import static org.elasticsearch.common.Strings.EMPTY_ARRAY;
-import static org.elasticsearch.common.settings.Settings.readSettingsFromStream;
 import static org.elasticsearch.common.xcontent.support.XContentMapValues.nodeBooleanValue;
 
 /**
@@ -58,8 +55,6 @@ public class CreateSnapshotRequest extends MasterNodeRequest<CreateSnapshotReque
         IndicesRequest.Replaceable,
         ToXContentObject {
 
-    public static final TransportVersion SETTINGS_IN_REQUEST_VERSION = TransportVersions.V_8_0_0;
-
     public static final int MAXIMUM_METADATA_BYTES = 1024; // chosen arbitrarily
 
     private String snapshot;
@@ -107,9 +102,6 @@ public CreateSnapshotRequest(StreamInput in) throws IOException {
         repository = in.readString();
         indices = in.readStringArray();
         indicesOptions = IndicesOptions.readIndicesOptions(in);
-        if (in.getTransportVersion().before(SETTINGS_IN_REQUEST_VERSION)) {
-            readSettingsFromStream(in);
-        }
         featureStates = in.readStringArray();
         includeGlobalState = in.readBoolean();
         waitForCompletion = in.readBoolean();
@@ -125,9 +117,6 @@ public void writeTo(StreamOutput out) throws IOException {
         out.writeString(repository);
         out.writeStringArray(indices);
         indicesOptions.writeIndicesOptions(out);
-        if (out.getTransportVersion().before(SETTINGS_IN_REQUEST_VERSION)) {
-            Settings.EMPTY.writeTo(out);
-        }
         out.writeStringArray(featureStates);
         out.writeBoolean(includeGlobalState);
         out.writeBoolean(waitForCompletion);

server/src/main/java/org/elasticsearch/action/admin/indices/create/CreateIndexRequest.java

@@ -87,19 +87,7 @@ public CreateIndexRequest(StreamInput in) throws IOException {
         cause = in.readString();
         index = in.readString();
         settings = readSettingsFromStream(in);
-        if (in.getTransportVersion().before(TransportVersions.V_8_0_0)) {
-            int size = in.readVInt();
-            assert size <= 1 : "Expected to read 0 or 1 mappings, but received " + size;
-            if (size == 1) {
-                String type = in.readString();
-                if (MapperService.SINGLE_MAPPING_NAME.equals(type) == false) {
-                    throw new IllegalArgumentException("Expected to receive mapping type of [_doc] but got [" + type + "]");
-                }
-                mappings = in.readString();
-            }
-        } else {
-            mappings = in.readString();
-        }
+        mappings = in.readString();
         int aliasesSize = in.readVInt();
         for (int i = 0; i < aliasesSize; i++) {
             aliases.add(new Alias(in));
@@ -510,17 +498,7 @@ public void writeTo(StreamOutput out) throws IOException {
         out.writeString(cause);
         out.writeString(index);
         settings.writeTo(out);
-        if (out.getTransportVersion().before(TransportVersions.V_8_0_0)) {
-            if ("{}".equals(mappings)) {
-                out.writeVInt(0);
-            } else {
-                out.writeVInt(1);
-                out.writeString(MapperService.SINGLE_MAPPING_NAME);
-                out.writeString(mappings);
-            }
-        } else {
-            out.writeString(mappings);
-        }
+        out.writeString(mappings);
         out.writeCollection(aliases);
         waitForActiveShards.writeTo(out);
         out.writeString(origin);

server/src/main/java/org/elasticsearch/action/admin/indices/forcemerge/ForceMergeRequest.java

@@ -9,8 +9,6 @@
 
 package org.elasticsearch.action.admin.indices.forcemerge;
 
-import org.elasticsearch.TransportVersion;
-import org.elasticsearch.TransportVersions;
 import org.elasticsearch.action.ActionRequestValidationException;
 import org.elasticsearch.action.support.broadcast.BroadcastRequest;
 import org.elasticsearch.common.UUIDs;
@@ -48,8 +46,6 @@ public static final class Defaults {
      */
     private boolean shouldStoreResult;
 
-    private static final TransportVersion FORCE_MERGE_UUID_SIMPLE_VERSION = TransportVersions.V_8_0_0;
-
     /**
      * Force merge UUID to store in the live commit data of a shard under
      * {@link org.elasticsearch.index.engine.Engine#FORCE_MERGE_UUID_KEY} after force merging it.
@@ -71,12 +67,7 @@ public ForceMergeRequest(StreamInput in) throws IOException {
         maxNumSegments = in.readInt();
         onlyExpungeDeletes = in.readBoolean();
         flush = in.readBoolean();
-        if (in.getTransportVersion().onOrAfter(FORCE_MERGE_UUID_SIMPLE_VERSION)) {
-            forceMergeUUID = in.readString();
-        } else {
-            forceMergeUUID = in.readOptionalString();
-            assert forceMergeUUID != null : "optional was just used as a BwC measure";
-        }
+        forceMergeUUID = in.readString();
     }
 
     /**
@@ -167,11 +158,7 @@ public void writeTo(StreamOutput out) throws IOException {
         out.writeInt(maxNumSegments);
         out.writeBoolean(onlyExpungeDeletes);
         out.writeBoolean(flush);
-        if (out.getTransportVersion().onOrAfter(FORCE_MERGE_UUID_SIMPLE_VERSION)) {
-            out.writeString(forceMergeUUID);
-        } else {
-            out.writeOptionalString(forceMergeUUID);
-        }
+        out.writeString(forceMergeUUID);
     }
 
     @Override

server/src/main/java/org/elasticsearch/action/admin/indices/stats/CommonStats.java

@@ -217,9 +217,7 @@ public CommonStats(StreamInput in) throws IOException {
         translog = in.readOptionalWriteable(TranslogStats::new);
         requestCache = in.readOptionalWriteable(RequestCacheStats::new);
         recoveryStats = in.readOptionalWriteable(RecoveryStats::new);
-        if (in.getTransportVersion().onOrAfter(TransportVersions.V_8_0_0)) {
-            bulk = in.readOptionalWriteable(BulkStats::new);
-        }
+        bulk = in.readOptionalWriteable(BulkStats::new);
         shards = in.readOptionalWriteable(ShardCountStats::new);
         if (in.getTransportVersion().onOrAfter(VERSION_SUPPORTING_NODE_MAPPINGS)) {
             nodeMappings = in.readOptionalWriteable(NodeMappingStats::new);
@@ -250,9 +248,7 @@ public void writeTo(StreamOutput out) throws IOException {
         out.writeOptionalWriteable(translog);
         out.writeOptionalWriteable(requestCache);
         out.writeOptionalWriteable(recoveryStats);
-        if (out.getTransportVersion().onOrAfter(TransportVersions.V_8_0_0)) {
-            out.writeOptionalWriteable(bulk);
-        }
+        out.writeOptionalWriteable(bulk);
         out.writeOptionalWriteable(shards);
         if (out.getTransportVersion().onOrAfter(VERSION_SUPPORTING_NODE_MAPPINGS)) {
             out.writeOptionalWriteable(nodeMappings);

server/src/main/java/org/elasticsearch/action/admin/indices/stats/CommonStatsFlags.java

@@ -9,8 +9,6 @@
 
 package org.elasticsearch.action.admin.indices.stats;
 
-import org.elasticsearch.TransportVersions;
-import org.elasticsearch.common.Strings;
 import org.elasticsearch.common.io.stream.StreamInput;
 import org.elasticsearch.common.io.stream.StreamOutput;
 import org.elasticsearch.common.io.stream.Writeable;
@@ -56,9 +54,6 @@ public CommonStatsFlags(StreamInput in) throws IOException {
                 flags.add(flag);
             }
         }
-        if (in.getTransportVersion().before(TransportVersions.V_8_0_0)) {
-            in.readStringArray();
-        }
         groups = in.readStringArray();
         fieldDataFields = in.readStringArray();
         completionDataFields = in.readStringArray();
@@ -73,10 +68,6 @@ public void writeTo(StreamOutput out) throws IOException {
             longFlags |= (1 << flag.getIndex());
         }
         out.writeLong(longFlags);
-
-        if (out.getTransportVersion().before(TransportVersions.V_8_0_0)) {
-            out.writeStringArrayNullable(Strings.EMPTY_ARRAY);
-        }
         out.writeStringArrayNullable(groups);
         out.writeStringArrayNullable(fieldDataFields);
         out.writeStringArrayNullable(completionDataFields);

server/src/main/java/org/elasticsearch/action/bulk/BulkItemResponse.java

@@ -22,7 +22,6 @@
 import org.elasticsearch.common.io.stream.StreamInput;
 import org.elasticsearch.common.io.stream.StreamOutput;
 import org.elasticsearch.common.io.stream.Writeable;
-import org.elasticsearch.index.mapper.MapperService;
 import org.elasticsearch.index.seqno.SequenceNumbers;
 import org.elasticsearch.index.shard.ShardId;
 import org.elasticsearch.rest.RestStatus;
@@ -189,11 +188,6 @@ private Failure(
          */
         public Failure(StreamInput in) throws IOException {
             index = in.readString();
-            if (in.getTransportVersion().before(TransportVersions.V_8_0_0)) {
-                in.readString();
-                // can't make an assertion about type names here because too many tests still set their own
-                // types bypassing various checks
-            }
             id = in.readOptionalString();
             cause = in.readException();
             status = ExceptionsHelper.status(cause);
@@ -210,9 +204,6 @@ public Failure(StreamInput in) throws IOException {
         @Override
         public void writeTo(StreamOutput out) throws IOException {
             out.writeString(index);
-            if (out.getTransportVersion().before(TransportVersions.V_8_0_0)) {
-                out.writeString(MapperService.SINGLE_MAPPING_NAME);
-            }
             out.writeOptionalString(id);
             out.writeException(cause);
             out.writeZLong(seqNo);

server/src/main/java/org/elasticsearch/action/delete/DeleteRequest.java

@@ -10,7 +10,6 @@
 package org.elasticsearch.action.delete;
 
 import org.apache.lucene.util.RamUsageEstimator;
-import org.elasticsearch.TransportVersions;
 import org.elasticsearch.action.ActionRequestValidationException;
 import org.elasticsearch.action.CompositeIndicesRequest;
 import org.elasticsearch.action.DocWriteRequest;
@@ -22,7 +21,6 @@
 import org.elasticsearch.common.lucene.uid.Versions;
 import org.elasticsearch.core.Nullable;
 import org.elasticsearch.index.VersionType;
-import org.elasticsearch.index.mapper.MapperService;
 import org.elasticsearch.index.shard.ShardId;
 
 import java.io.IOException;
@@ -63,10 +61,6 @@ public DeleteRequest(StreamInput in) throws IOException {
 
     public DeleteRequest(@Nullable ShardId shardId, StreamInput in) throws IOException {
         super(shardId, in);
-        if (in.getTransportVersion().before(TransportVersions.V_8_0_0)) {
-            String type = in.readString();
-            assert MapperService.SINGLE_MAPPING_NAME.equals(type) : "Expected [_doc] but received [" + type + "]";
-        }
         id = in.readString();
         routing = in.readOptionalString();
         version = in.readLong();
@@ -255,9 +249,6 @@ public void writeThin(StreamOutput out) throws IOException {
     }
 
     private void writeBody(StreamOutput out) throws IOException {
-        if (out.getTransportVersion().before(TransportVersions.V_8_0_0)) {
-            out.writeString(MapperService.SINGLE_MAPPING_NAME);
-        }
         out.writeString(id);
         out.writeOptionalString(routing());
         out.writeLong(version);

server/src/main/java/org/elasticsearch/action/explain/ExplainRequest.java

@@ -9,14 +9,12 @@
 
 package org.elasticsearch.action.explain;
 
-import org.elasticsearch.TransportVersions;
 import org.elasticsearch.action.ActionRequestValidationException;
 import org.elasticsearch.action.ValidateActions;
 import org.elasticsearch.action.support.single.shard.SingleShardRequest;
 import org.elasticsearch.common.Strings;
 import org.elasticsearch.common.io.stream.StreamInput;
 import org.elasticsearch.common.io.stream.StreamOutput;
-import org.elasticsearch.index.mapper.MapperService;
 import org.elasticsearch.index.query.QueryBuilder;
 import org.elasticsearch.search.fetch.subphase.FetchSourceContext;
 import org.elasticsearch.search.internal.AliasFilter;
@@ -55,10 +53,6 @@ public ExplainRequest(String index, String id) {
 
     ExplainRequest(StreamInput in) throws IOException {
         super(in);
-        if (in.getTransportVersion().before(TransportVersions.V_8_0_0)) {
-            String type = in.readString();
-            assert MapperService.SINGLE_MAPPING_NAME.equals(type);
-        }
         id = in.readString();
         routing = in.readOptionalString();
         preference = in.readOptionalString();
@@ -161,9 +155,6 @@ public ActionRequestValidationException validate() {
     @Override
     public void writeTo(StreamOutput out) throws IOException {
         super.writeTo(out);
-        if (out.getTransportVersion().before(TransportVersions.V_8_0_0)) {
-            out.writeString(MapperService.SINGLE_MAPPING_NAME);
-        }
         out.writeString(id);
         out.writeOptionalString(routing);
         out.writeOptionalString(preference);