fix bug in parent handling where the parsed parent value was not set in the SourceToParse

modules/elasticsearch/src/main/java/org/elasticsearch/index/mapper/internal/ParentFieldMapper.java

@@ -122,6 +122,7 @@ public class ParentFieldMapper extends AbstractFieldMapper<Uid> implements Inter
         if (context.parser().currentName() != null && context.parser().currentName().equals(Defaults.NAME)) {
             // we are in the parsing of _parent phase
             String parentId = context.parser().text();
+            context.sourceToParse().parent(parentId);
             return new Field(names.indexName(), Uid.createUid(context.stringBuilder(), type, parentId), store, index);
         }
         // otherwise, we are running it post processing of the xcontent

modules/elasticsearch/src/test/java/org/elasticsearch/index/mapper/parent/ParentMappingTests.java

@@ -48,6 +48,7 @@ public class ParentMappingTests {
                 .copiedBytes()).type("type").id("1"));
 
         // no _parent mapping, used as a simple field
+        assertThat(doc.parent(), equalTo(null));
         assertThat(doc.rootDoc().get("_parent"), equalTo("1122"));
     }
 
@@ -64,6 +65,7 @@ public class ParentMappingTests {
                 .endObject()
                 .copiedBytes()).type("type").id("1"));
         
+        assertThat(doc.parent(), equalTo("1122"));
         assertThat(doc.rootDoc().get("_parent"), equalTo(Uid.createUid("p_type", "1122")));
     }