Throw better exception on wrong dynamic_templates syntax (#51783)

Currently, a mappings update request, where dynamic_mappings is an object instead of an array, results in a http response with a 500 code. This PR checks for this condition and throws a MapperParsingException like we do for other malformed mapping cases. Closes #51486
elastic · Feb 4, 2020 · 337153b · 337153b
1 parent b7aace4
commit 337153b
Show file tree

Hide file tree

Showing 2 changed files with 18 additions and 0 deletions.
diff --git a/server/src/main/java/org/elasticsearch/index/mapper/RootObjectMapper.java b/server/src/main/java/org/elasticsearch/index/mapper/RootObjectMapper.java
@@ -163,6 +163,9 @@ protected boolean processField(RootObjectMapper.Builder builder, String fieldNam
                 //          }
                 //      }
                 //  ]
+                if ((fieldNode instanceof List) == false) {
+                    throw new MapperParsingException("Dynamic template syntax error. An array of named objects is expected.");
+                }
                 List<?> tmplNodes = (List<?>) fieldNode;
                 List<DynamicTemplate> templates = new ArrayList<>();
                 for (Object tmplNode : tmplNodes) {

diff --git a/server/src/test/java/org/elasticsearch/index/mapper/RootObjectMapperTests.java b/server/src/test/java/org/elasticsearch/index/mapper/RootObjectMapperTests.java
@@ -185,4 +185,19 @@ public void testIllegalFormatField() throws Exception {
             assertEquals("Invalid format: [[test_format]]: expected string value", e.getMessage());
         }
     }
+
+    public void testIllegalDynamicTemplates() throws Exception {
+        String mapping = Strings.toString(XContentFactory.jsonBuilder()
+                .startObject()
+                .startObject("type")
+                    .startObject("dynamic_templates")
+                    .endObject()
+                .endObject()
+            .endObject());
+
+        DocumentMapperParser parser = createIndex("test").mapperService().documentMapperParser();
+        MapperParsingException e = expectThrows(MapperParsingException.class,
+                    () -> parser.parse("type", new CompressedXContent(mapping)));
+        assertEquals("Dynamic template syntax error. An array of named objects is expected.", e.getMessage());
+    }
 }