From b3afb5f7ee3b8339795154ac26b49cd2e2b066c0 Mon Sep 17 00:00:00 2001
From: Felipe Reis <freis@atlassian.com>
Date: Thu, 1 Feb 2024 14:11:50 +1100
Subject: [PATCH] Fix oneOf bug when variables is empty

---
 .../ValuesResolverOneOfValidation.java        | 39 ++++++++++++-------
 .../execution/ValuesResolverTest.groovy       |  3 ++
 2 files changed, 29 insertions(+), 13 deletions(-)

diff --git a/src/main/java/graphql/execution/ValuesResolverOneOfValidation.java b/src/main/java/graphql/execution/ValuesResolverOneOfValidation.java
index 6456ffaa01..c0f98f5523 100644
--- a/src/main/java/graphql/execution/ValuesResolverOneOfValidation.java
+++ b/src/main/java/graphql/execution/ValuesResolverOneOfValidation.java
@@ -75,23 +75,36 @@ static void validateOneOfInputTypes(GraphQLType type, Object inputValue, Value<?
     }
 
     private static void validateOneOfInputTypesInternal(GraphQLInputObjectType oneOfInputType, Value<?> argumentValue, Map<String, Object> objectMap, Locale locale) {
-        int mapSize;
-
+        final String fieldName;
         if (argumentValue instanceof ObjectValue) {
-            mapSize = ((ObjectValue) argumentValue).getObjectFields().size();
+            List<ObjectField> objectFields = ((ObjectValue) argumentValue).getObjectFields();
+            if (objectFields.size() != 1) {
+                throwNotOneFieldError(oneOfInputType, locale);
+            }
+
+            fieldName = objectFields.iterator().next().getName();
         } else {
-            mapSize = objectMap.size();
-        }
-        if (mapSize != 1) {
-            String msg = I18n.i18n(I18n.BundleType.Execution, locale)
-                    .msg("Execution.handleOneOfNotOneFieldError", oneOfInputType.getName());
-            throw new OneOfTooManyKeysException(msg);
+            if (objectMap.size() != 1) {
+                throwNotOneFieldError(oneOfInputType, locale);
+            }
+
+            fieldName = objectMap.keySet().iterator().next();
         }
-        String fieldName = objectMap.keySet().iterator().next();
+
         if (objectMap.get(fieldName) == null) {
-            String msg = I18n.i18n(I18n.BundleType.Execution, locale)
-                    .msg("Execution.handleOneOfValueIsNullError", oneOfInputType.getName() + "." + fieldName);
-            throw new OneOfNullValueException(msg);
+            throwValueIsNullError(oneOfInputType, locale, fieldName);
         }
     }
+
+    private static void throwValueIsNullError(GraphQLInputObjectType oneOfInputType, Locale locale, String fieldName) {
+        String msg = I18n.i18n(I18n.BundleType.Execution, locale)
+                .msg("Execution.handleOneOfValueIsNullError", oneOfInputType.getName() + "." + fieldName);
+        throw new OneOfNullValueException(msg);
+    }
+
+    private static void throwNotOneFieldError(GraphQLInputObjectType oneOfInputType, Locale locale) {
+        String msg = I18n.i18n(I18n.BundleType.Execution, locale)
+                .msg("Execution.handleOneOfNotOneFieldError", oneOfInputType.getName());
+        throw new OneOfTooManyKeysException(msg);
+    }
 }
diff --git a/src/test/groovy/graphql/execution/ValuesResolverTest.groovy b/src/test/groovy/graphql/execution/ValuesResolverTest.groovy
index 8e40ac4433..83488658d2 100644
--- a/src/test/groovy/graphql/execution/ValuesResolverTest.groovy
+++ b/src/test/groovy/graphql/execution/ValuesResolverTest.groovy
@@ -600,6 +600,9 @@ class ValuesResolverTest extends Specification {
                 a: VariableReference.of("var")
         ])                                            | CoercedVariables.of(["var": null])
 
+        '`{ a: $var }`  { }' | buildObjectLiteral([
+                a: VariableReference.of("var")
+        ])                                            | CoercedVariables.emptyVariables()
     }
 
     def "getArgumentValues: invalid oneOf list input because element contains duplicate key - #testCase"() {