Adjust SearchRequest version checks (#38181)

The finalReduce flag is now supported on 6.x too, hence we need to update the version checks in master.

Author: javanna

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

@@ -205,17 +205,14 @@ public SearchRequest(StreamInput in) throws IOException {
             localClusterAlias = in.readOptionalString();
             if (localClusterAlias != null) {
                 absoluteStartMillis = in.readVLong();
+                finalReduce = in.readBoolean();
             } else {
                 absoluteStartMillis = DEFAULT_ABSOLUTE_START_MILLIS;
+                finalReduce = true;
             }
         } else {
             localClusterAlias = null;
             absoluteStartMillis = DEFAULT_ABSOLUTE_START_MILLIS;
-        }
-        //TODO move to the 6_7_0 branch once backported to 6.x
-        if (in.getVersion().onOrAfter(Version.V_7_0_0)) {
-            finalReduce = in.readBoolean();
-        } else {
             finalReduce = true;
         }
         if (in.getVersion().onOrAfter(Version.V_7_0_0)) {
@@ -245,12 +242,9 @@ public void writeTo(StreamOutput out) throws IOException {
             out.writeOptionalString(localClusterAlias);
             if (localClusterAlias != null) {
                 out.writeVLong(absoluteStartMillis);
+                out.writeBoolean(finalReduce);
             }
         }
-        //TODO move to the 6_7_0 branch once backported to 6.x
-        if (out.getVersion().onOrAfter(Version.V_7_0_0)) {
-            out.writeBoolean(finalReduce);
-        }
         if (out.getVersion().onOrAfter(Version.V_7_0_0)) {
             out.writeBoolean(ccsMinimizeRoundtrips);
         }

server/src/test/java/org/elasticsearch/action/search/SearchRequestTests.java

@@ -91,14 +91,10 @@ public void testRandomVersionSerialization() throws IOException {
         if (version.before(Version.V_6_7_0)) {
             assertNull(deserializedRequest.getLocalClusterAlias());
             assertAbsoluteStartMillisIsCurrentTime(deserializedRequest);
+            assertTrue(deserializedRequest.isFinalReduce());
         } else {
             assertEquals(searchRequest.getLocalClusterAlias(), deserializedRequest.getLocalClusterAlias());
             assertEquals(searchRequest.getOrCreateAbsoluteStartMillis(), deserializedRequest.getOrCreateAbsoluteStartMillis());
-        }
-        //TODO move to the 6_7_0 branch once backported to 6.x
-        if (version.before(Version.V_7_0_0)) {
-            assertTrue(deserializedRequest.isFinalReduce());
-        } else {
             assertEquals(searchRequest.isFinalReduce(), deserializedRequest.isFinalReduce());
         }
     }

server/src/test/java/org/elasticsearch/action/search/TransportSearchActionSingleNodeTests.java

@@ -171,6 +171,7 @@ public void testFinalReduce()  {
             assertEquals(2, searchResponse.getHits().getTotalHits().value);
             Aggregations aggregations = searchResponse.getAggregations();
             LongTerms longTerms = aggregations.get("terms");
+            assertEquals(2, longTerms.getBuckets().size());
         }
     }
 }