Add textRefOrNull to DotExpandingXContentParser

Author: jordan-powers

server/src/main/java/org/elasticsearch/index/mapper/DotExpandingXContentParser.java

@@ -10,6 +10,7 @@
 package org.elasticsearch.index.mapper;
 
 import org.elasticsearch.core.CheckedFunction;
+import org.elasticsearch.xcontent.ESBytesRef;
 import org.elasticsearch.xcontent.FilterXContentParser;
 import org.elasticsearch.xcontent.FilterXContentParserWrapper;
 import org.elasticsearch.xcontent.XContentLocation;
@@ -379,6 +380,14 @@ public void skipChildren() throws IOException {
         }
     }
 
+    @Override
+    public ESBytesRef textRefOrNull() throws IOException {
+        if (state == State.EXPANDING_START_OBJECT) {
+            throw new IllegalStateException("Can't get text on a " + currentToken() + " at " + getTokenLocation());
+        }
+        return super.textRefOrNull();
+    }
+
     @Override
     public String textOrNull() throws IOException {
         if (state == State.EXPANDING_START_OBJECT) {