Do not throw exception when flat_object field is explicitly null

It is valid for a flat_object field to have an explicit value of null. (It's functionally the same as not specifying the field at all.) Prior to this fix, though, we would erroneously advance the context parser to the next token, violating the contract with DocumentParser (which says that a call to parseCreateField with a null value should complete with the parser still pointing at the null value -- it is DocumentParser's responsibility to advance). Signed-off-by: Michael Froh <[email protected]>
msfroh · Aug 23, 2024 · b416205 · b416205
1 parent ed65482
commit b416205
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diff --git a/rest-api-spec/src/main/resources/rest-api-spec/test/index/100_partial_flat_object.yml b/rest-api-spec/src/main/resources/rest-api-spec/test/index/100_partial_flat_object.yml
@@ -88,7 +88,16 @@ setup:
             } ]
           }
         }
-
+  - do:
+      index:
+        index: test_partial_flat_object
+        id: 4
+        body: {
+          "issue": {
+            "number": 999,
+            "labels": null
+          }
+        }
   - do:
       indices.refresh:
         index: test_partial_flat_object
@@ -135,7 +144,7 @@ teardown:
           }
         }
 
-  - length: { hits.hits: 3 }
+  - length: { hits.hits: 4 }
 
   # Match Query with exact dot path.
   - do:

diff --git a/server/src/main/java/org/opensearch/index/mapper/FlatObjectFieldMapper.java b/server/src/main/java/org/opensearch/index/mapper/FlatObjectFieldMapper.java
@@ -568,11 +568,7 @@ protected void parseCreateField(ParseContext context) throws IOException {
         if (context.externalValueSet()) {
             String value = context.externalValue().toString();
             parseValueAddFields(context, value, fieldType().name());
-        } else if (context.parser().currentToken() == XContentParser.Token.VALUE_NULL) {
-            context.parser().nextToken(); // This triggers an exception in DocumentParser.
-            // We could remove the above nextToken() call to skip the null value, but the existing
-            // behavior (since 2.7) throws the exception.
-        } else {
+        } else if (context.parser().currentToken() != XContentParser.Token.VALUE_NULL) {
             JsonToStringXContentParser jsonToStringParser = new JsonToStringXContentParser(
                 NamedXContentRegistry.EMPTY,
                 DeprecationHandler.IGNORE_DEPRECATIONS,