Internal: fixed bw comp in ShardSearchTransportRequest

Original indices were introduced in 1.4.0.Beta1 as optional, preceded by a boolean flag that told whether they were empty or not. We have to keep serializing as optional only when reading and writing from/to 1.4.0.Beta1, although the original indices are not optional whenever we go and serialize the request they belong to (which is why the boolean got removed in 1.4.0).

Author: javanna

src/main/java/org/elasticsearch/search/internal/ShardSearchTransportRequest.java

@@ -19,6 +19,7 @@
 
 package org.elasticsearch.search.internal;
 
+import org.elasticsearch.Version;
 import org.elasticsearch.action.IndicesRequest;
 import org.elasticsearch.action.OriginalIndices;
 import org.elasticsearch.action.search.SearchRequest;
@@ -163,13 +164,23 @@ public void readFrom(StreamInput in) throws IOException {
         super.readFrom(in);
         shardSearchLocalRequest = new ShardSearchLocalRequest();
         shardSearchLocalRequest.innerReadFrom(in);
+        if (in.getVersion().onOrAfter(Version.V_1_4_0_Beta1) && in.getVersion().before(Version.V_1_4_0)) {
+            //original indices used to be optional in 1.4.0.Beta1 but ended up being empty only when the
+            // shard search request was used locally and never serialized
+            in.readBoolean();
+        }
         originalIndices = OriginalIndices.readOriginalIndices(in);
     }
 
     @Override
     public void writeTo(StreamOutput out) throws IOException {
         super.writeTo(out);
         shardSearchLocalRequest.innerWriteTo(out, false);
+        if (out.getVersion().onOrAfter(Version.V_1_4_0_Beta1) && out.getVersion().before(Version.V_1_4_0)) {
+            //original indices used to be optional in 1.4.0.Beta1 although ended up being empty only when the
+            //shard search request was used locally and never serialized
+            out.writeBoolean(true);
+        }
         OriginalIndices.writeOriginalIndices(originalIndices, out);
     }