Serialize BackedEnum instances by name, not value

Author: spawnia

CHANGELOG.md

@@ -9,6 +9,12 @@ You can find and compare releases at the [GitHub release page](https://github.co
 
 ## Unreleased
 
+## v15.14.3
+
+### Fixed
+
+- Serialize `BackedEnum` instances by name, not value https://github.com/webonyx/graphql-php/pull/1618
+
 ## v15.14.2
 
 ### Changed

src/Type/Definition/EnumType.php

@@ -137,7 +137,7 @@ public function serialize($value)
         }
 
         if (is_a($value, \BackedEnum::class)) {
-            return $value->value;
+            return $value->name;
         }
 
         if (is_a($value, \UnitEnum::class)) {

tests/Type/PhpEnumType/BackedPhpEnum.php

@@ -4,7 +4,7 @@
 
 enum BackedPhpEnum: string
 {
-    case A = 'A';
+    case A = 'a';
     case B = 'B';
-    case C = 'C';
+    case C = 'the value does not really matter';
 }