Mappings: Validate parsed document does not have trailing garbage that is invalid json

This remerges PR #11414. The added validation for trailing garbage is
now only done when the parse method created the parser.

core/src/main/java/org/elasticsearch/index/mapper/DocumentParser.java

@@ -25,6 +25,7 @@ import org.apache.lucene.document.Field;
 import org.apache.lucene.index.IndexOptions;
 import org.apache.lucene.index.IndexableField;
 import org.apache.lucene.util.CloseableThreadLocal;
+import org.elasticsearch.Version;
 import org.elasticsearch.common.Strings;
 import org.elasticsearch.common.joda.FormatDateTimeFormatter;
 import org.elasticsearch.common.settings.Settings;
@@ -42,6 +43,7 @@ import org.elasticsearch.index.mapper.internal.UidFieldMapper;
 import org.elasticsearch.index.mapper.object.ArrayValueMapperParser;
 import org.elasticsearch.index.mapper.object.ObjectMapper;
 import org.elasticsearch.index.mapper.object.RootObjectMapper;
+import org.elasticsearch.percolator.PercolatorService;
 
 import java.io.Closeable;
 import java.io.IOException;
@@ -127,6 +129,15 @@ class DocumentParser implements Closeable {
                 parser.nextToken();
             }
 
+            // try to parse the next token, this should be null if the object is ended properly
+            // but will throw a JSON exception if the extra tokens is not valid JSON (this will be handled by the catch)
+            if (Version.indexCreated(indexSettings).onOrAfter(Version.V_2_0_0_beta1)
+                && source.parser() == null && parser != null) {
+                // only check for end of tokens if we created the parser here
+                token = parser.nextToken();
+                assert token == null; // double check, in tests, that we didn't end parsing early
+            }
+
             for (MetadataFieldMapper metadataMapper : mapping.metadataMappers) {
                 metadataMapper.postParse(context);
             }

core/src/test/java/org/elasticsearch/index/mapper/source/DefaultSourceMappingTests.java

@@ -309,4 +309,18 @@ public class DefaultSourceMappingTests extends ESSingleNodeTestCase {
             .endObject().endObject().string();
         assertFalse(parser.parse(mapping).sourceMapper().isComplete());
     }
+
+    public void testSourceObjectContainsExtraTokens() throws Exception {
+        String mapping = XContentFactory.jsonBuilder().startObject().startObject("type").endObject().endObject().string();
+        DocumentMapper documentMapper = createIndex("test").mapperService().documentMapperParser().parse(mapping);
+
+        try {
+            documentMapper.parse("test", "type", "1", new BytesArray("{}}")); // extra end object (invalid JSON)
+            fail("Expected parse exception");
+        } catch (MapperParsingException e) {
+            assertNotNull(e.getRootCause());
+            String message = e.getRootCause().getMessage();
+            assertTrue(message, message.contains("Unexpected close marker '}'"));
+        }
+    }
 }