Fix implementation of currentValueHash in FieldDataSource.Bytes.SortedAndUnique.

Close elastic#4330

Author: jpountz

src/main/java/org/elasticsearch/search/aggregations/bucket/terms/StringTermsAggregator.java

@@ -79,6 +79,7 @@ public void collect(int doc, long owningBucketOrdinal) throws IOException {
  continue;
  }
  final int hash = values.currentValueHash();
+ assert hash == bytes.hashCode();
  int bucketOrdinal = bucketOrds.add(bytes, hash);
  if (bucketOrdinal < 0) { // already seen
  bucketOrdinal = - 1 - bucketOrdinal;

src/main/java/org/elasticsearch/search/aggregations/support/FieldDataSource.java

@@ -166,7 +166,7 @@ public int setDocument(int docId) {
  bytes.clear();
  bytes.reinit();
  for (int i = 0; i < numValues; ++i) {
- bytes.add(super.nextValue(), super.hashCode());
+ bytes.add(super.nextValue(), super.currentValueHash());
  }
  numUniqueValues = bytes.size();
  sortedIds = bytes.sort(BytesRef.getUTF8SortedAsUnicodeComparator());
@@ -180,6 +180,11 @@ public BytesRef nextValue() {
  return spare;
  }
 
+ @Override
+ public int currentValueHash() {
+ return spare.hashCode();
+ }
+
  @Override
  public Order getOrder() {
  return Order.BYTES;