From 04550f805fbe452612cf9256efad28ca54096a39 Mon Sep 17 00:00:00 2001
From: vladar <vladimir.razuvaev@gmail.com>
Date: Sat, 19 Nov 2016 17:21:22 +0700
Subject: [PATCH] Differentiate between input values with no default and with
 default = null

---
 src/Type/Introspection.php       |  7 ++++++-
 tests/Type/IntrospectionTest.php | 34 +++++++++++++++++++++++---------
 2 files changed, 31 insertions(+), 10 deletions(-)

diff --git a/src/Type/Introspection.php b/src/Type/Introspection.php
index 6a325f5..5b44f50 100644
--- a/src/Type/Introspection.php
+++ b/src/Type/Introspection.php
@@ -6,7 +6,9 @@ use GraphQL\Language\Printer;
 use GraphQL\Schema;
 use GraphQL\Type\Definition\Directive;
 use GraphQL\Type\Definition\EnumType;
+use GraphQL\Type\Definition\FieldArgument;
 use GraphQL\Type\Definition\FieldDefinition;
+use GraphQL\Type\Definition\InputObjectField;
 use GraphQL\Type\Definition\InputObjectType;
 use GraphQL\Type\Definition\InterfaceType;
 use GraphQL\Type\Definition\ListOfType;
@@ -613,8 +615,11 @@ EOD;
                         ],
                         'defaultValue' => [
                             'type' => Type::string(),
+                            'description' =>
+                                'A GraphQL-formatted string representing the default value for this input value.',
                             'resolve' => function ($inputValue) {
-                                return $inputValue->defaultValue === null
+                                /** @var FieldArgument|InputObjectField $inputValue */
+                                return !$inputValue->defaultValueExists()
                                     ? null
                                     : Printer::doPrint(AST::astFromValue($inputValue->defaultValue, $inputValue->getType()));
                             }
diff --git a/tests/Type/IntrospectionTest.php b/tests/Type/IntrospectionTest.php
index 3c10912..ac24e46 100644
--- a/tests/Type/IntrospectionTest.php
+++ b/tests/Type/IntrospectionTest.php
@@ -1079,7 +1079,8 @@ class IntrospectionTest extends \PHPUnit_Framework_TestCase
             'name' => 'TestInputObject',
             'fields' => [
                 'a' => ['type' => Type::string(), 'defaultValue' => 'foo'],
-                'b' => ['type' => Type::listOf(Type::string())]
+                'b' => ['type' => Type::listOf(Type::string())],
+                'c' => ['type' => Type::string(), 'defaultValue' => null ]
             ]
         ]);
 
@@ -1135,17 +1136,32 @@ class IntrospectionTest extends \PHPUnit_Framework_TestCase
             'kind' => 'INPUT_OBJECT',
             'name' => 'TestInputObject',
             'inputFields' => [
-                ['name' => 'a', 'type' => [
-                    'kind' => 'SCALAR',
-                    'name' => 'String',
-                    'ofType' => null],
+                [
+                    'name' => 'a',
+                    'type' => [
+                        'kind' => 'SCALAR',
+                        'name' => 'String',
+                        'ofType' => null
+                    ],
                     'defaultValue' => '"foo"'
                 ],
-                ['name' => 'b', 'type' => [
-                    'kind' => 'LIST',
-                    'name' => null,
-                    'ofType' => ['kind' => 'SCALAR', 'name' => 'String', 'ofType' => null]],
+                [
+                    'name' => 'b',
+                    'type' => [
+                        'kind' => 'LIST',
+                        'name' => null,
+                        'ofType' => ['kind' => 'SCALAR', 'name' => 'String', 'ofType' => null]
+                    ],
                     'defaultValue' => null
+                ],
+                [
+                    'name' => 'c',
+                    'type' => [
+                        'kind' => 'SCALAR',
+                        'name' => 'String',
+                        'ofType' => null
+                    ],
+                    'defaultValue' => 'null' // defaultValue was set (even if it was set to null)
                 ]
             ]
         ];