Search fails when sorting on a field that has no values in the hits returned, closes #285.

modules/elasticsearch/src/main/java/org/elasticsearch/action/search/type/TransportSearchTypeAction.java

@@ -217,6 +217,13 @@ public abstract class TransportSearchTypeAction extends BaseAction<SearchRequest
                 try {
                     moveToSecondPhase();
                 } catch (Exception e) {
+                    if (logger.isDebugEnabled()) {
+                        if (shard != null) {
+                            logger.debug(shard.shortSummary() + ": Failed to execute [" + request + "] while moving to second phase", e);
+                        } else {
+                            logger.debug(shardIt.shardId() + ": Failed to execute [" + request + "] while moving to second phase", e);
+                        }
+                    }
                     invokeListener(new ReduceSearchPhaseException(firstPhaseName(), "", e, buildShardFailures()));
                 }
             }

modules/elasticsearch/src/main/java/org/elasticsearch/search/controller/SearchPhaseController.java

@@ -80,14 +80,16 @@ public class SearchPhaseController {
         }
         PriorityQueue queue;
         if (queryResultProvider.queryResult().topDocs() instanceof TopFieldDocs) {
-            // sorting, first if the type is a String, chance CUSTOM to STRING so we handle nulls properly
+            // sorting, first if the type is a String, chance CUSTOM to STRING so we handle nulls properly (since our CUSTOM String sorting might return null)
             TopFieldDocs fieldDocs = (TopFieldDocs) queryResultProvider.queryResult().topDocs();
             for (int i = 0; i < fieldDocs.fields.length; i++) {
+                boolean allValuesAreNull = true;
                 boolean resolvedField = false;
                 for (QuerySearchResultProvider resultProvider : results) {
                     for (ScoreDoc doc : resultProvider.queryResult().topDocs().scoreDocs) {
                         FieldDoc fDoc = (FieldDoc) doc;
                         if (fDoc.fields[i] != null) {
+                            allValuesAreNull = false;
                             if (fDoc.fields[i] instanceof String) {
                                 fieldDocs.fields[i] = new SortField(fieldDocs.fields[i].getField(), SortField.STRING, fieldDocs.fields[i].getReverse());
                             }
@@ -99,6 +101,10 @@ public class SearchPhaseController {
                         break;
                     }
                 }
+                if (!resolvedField && allValuesAreNull) {
+                    // we did not manage to resolve a field, and all the fields are null (which can only happen for STRING), make it a STRING
+                    fieldDocs.fields[i] = new SortField(fieldDocs.fields[i].getField(), SortField.STRING, fieldDocs.fields[i].getReverse());
+                }
             }
             queue = new ShardFieldDocSortedHitQueue(fieldDocs.fields, queueSize);
 

modules/test/integration/src/test/java/org/elasticsearch/test/integration/search/sort/SimpleSortTests.java

@@ -206,5 +206,23 @@ public class SimpleSortTests extends AbstractNodesTests {
         assertThat((String) searchResponse.hits().getAt(0).field("id").value(), equalTo("3"));
         assertThat((String) searchResponse.hits().getAt(1).field("id").value(), equalTo("1"));
         assertThat((String) searchResponse.hits().getAt(2).field("id").value(), equalTo("2"));
+
+        // a query with docs just with null values
+        searchResponse = client.prepareSearch()
+                .setQuery(termQuery("id", "2"))
+                .addScriptField("id", "doc['id'].value")
+                .addSort("svalue", SearchSourceBuilder.Order.DESC)
+                .execute().actionGet();
+
+        if (searchResponse.failedShards() > 0) {
+            logger.warn("Failed shards:");
+            for (ShardSearchFailure shardSearchFailure : searchResponse.shardFailures()) {
+                logger.warn("-> {}", shardSearchFailure);
+            }
+        }
+        assertThat(searchResponse.failedShards(), equalTo(0));
+
+        assertThat(searchResponse.hits().getTotalHits(), equalTo(1l));
+        assertThat((String) searchResponse.hits().getAt(0).field("id").value(), equalTo("2"));
     }
 }