Throw a more meaningful message when no document is specified for indexing

src/main/java/org/elasticsearch/index/mapper/DocumentMapper.java

@@ -537,6 +537,11 @@ public class DocumentMapper implements ToXContent {
                 throw (MapperParsingException) e;
             }
 
+            // Throw a more meaningful message if the document is empty.
+            if (source.source() != null && source.source().length() == 0) {
+                throw new MapperParsingException("failed to parse, document is empty");
+            }
+
             throw new MapperParsingException("failed to parse", e);
         } finally {
             // only close the parser when its not provided externally

src/test/java/org/elasticsearch/test/unit/index/mapper/simple/SimpleMapperTests.java

@@ -24,6 +24,7 @@ import org.elasticsearch.common.bytes.BytesArray;
 import org.elasticsearch.common.bytes.BytesReference;
 import org.elasticsearch.index.mapper.DocumentMapper;
 import org.elasticsearch.index.mapper.DocumentMapperParser;
+import org.elasticsearch.index.mapper.MapperParsingException;
 import org.elasticsearch.index.mapper.Uid;
 import org.elasticsearch.test.unit.index.mapper.MapperTests;
 import org.testng.annotations.Test;
@@ -113,4 +114,21 @@ public class SimpleMapperTests {
         DocumentMapper builtDocMapper = MapperTests.newParser().parse(builtMapping);
         assertThat((String) builtDocMapper.meta().get("param1"), equalTo("value1"));
     }
+
+    @Test
+    public void testNoDocumentSent() throws Exception {
+        DocumentMapperParser mapperParser = MapperTests.newParser();
+        DocumentMapper docMapper = doc("test",
+                rootObject("person")
+                        .add(object("name").add(stringField("first").store(true).index(false)))
+        ).build(mapperParser);
+
+        BytesReference json = new BytesArray("".getBytes());
+        try {
+            docMapper.parse("person", "1", json).rootDoc();
+            assertThat("this point is never reached", false);
+        } catch (MapperParsingException e) {
+            assertThat(e.getMessage(), equalTo("failed to parse, document is empty"));
+        }
+    }
 }