Force fields to be optional with "update" input

Author: devmaslov

docs/annotations_reference.md

@@ -66,7 +66,7 @@ Attribute      | Compulsory | Type   | Definition
 name           | *no*       | string | The name of the GraphQL input type generated. If not passed, the name of the class with suffix "Input" is used. If the class ends with "Input", the "Input" suffix is not added.
 description    | *no*       | string | Description of the input type in the documentation. If not passed, PHP doc comment is used.
 default        | *no*       | bool   | Defaults to *true* if name is not specified. Whether the annotated PHP class should be mapped by default to this type.
-update         | *no*       | bool   | Determines if the the input represents a partial update. When set to *true* input fields won't have default values thus won't be set on resolve if they are not specified in the query/mutation.
+update         | *no*       | bool   | Determines if the the input represents a partial update. When set to *true* all input fields will become optional and won't have default values thus won't be set on resolve if they are not specified in the query/mutation.
 
 
 ## @Field annotation

docs/input_types.md

@@ -547,7 +547,7 @@ There are 2 input types created for just one class: `CreateUserInput` and `Updat
 - Field `age` is optional for both input types.
 
 Note that `update: true` argument for `UpdateUserInput`. It should be used when input type is used for a partial update,
-It removes all default values from all fields thus prevents setting default values via setters or directly to public properties.
+It makes all fields optional and removes all default values from thus prevents setting default values via setters or directly to public properties.
 In example above if you use the class as `UpdateUserInput` and set only `username` the other ones will be ignored.
 In PHP 7 they will be set to `null`, while in PHP 8 they will be in not initialized state - this can be used as a trick
 to check if user actually passed a value for a certain field.

src/Types/InputType.php

@@ -4,6 +4,7 @@
 
 namespace TheCodingMachine\GraphQLite\Types;
 
+use GraphQL\Type\Definition\NonNull;
 use GraphQL\Type\Definition\ResolveInfo;
 use ReflectionClass;
 use TheCodingMachine\GraphQLite\FailedResolvingInputType;
@@ -40,6 +41,10 @@ public function __construct(string $className, string $inputName, ?string $descr
             foreach ($this->fields as $name => $field) {
                 $type = $field->getType();
 
+                if ($isUpdate && $type instanceof NonNull) {
+                    $type = $type->getWrappedType();
+                }
+
                 $fields[$name] = [
                     'type' => $type,
                     'description' => $field->getDescription(),

tests/Fixtures/Integration/Models/Post.php

@@ -52,6 +52,12 @@ class Post
      */
     public $author = null;
 
+    /**
+     * @Field(for="UpdatePostInput")
+     * @var int
+     */
+    public $views;
+
     /**
      * @Field(for="UpdatePostInput")
      * @var string|null