WIP - Add wildcard to inject directive

CHANGELOG.md

@@ -9,6 +9,8 @@ You can find and compare releases at the [GitHub release page](https://github.co
 
 ## Unreleased
 
+- Allow to set value using asterisks as a wildcard in `@inject` https://github.com/nuwave/lighthouse/pull/2280
+
 ### Changed
 
 - Pass resolver arguments to `FieldBuilderDirective::handleFieldBuilder()` https://github.com/nuwave/lighthouse/pull/2234

docs/master/api-reference/directives.md

@@ -1729,6 +1729,7 @@ directive @inject(
   The target name of the argument into which the value is injected.
   You can use dot notation to set the value at arbitrary depth
   within the incoming argument.
+  Use an asterisk `*` as a path segment where the value of the argument is a list to be traversed.
   """
   name: String!
 ) repeatable on FIELD_DEFINITION
@@ -1756,6 +1757,16 @@ type Mutation {
 }
 ```
 
+If you have an array you need to inject a value into, you can use an asterisk `*`. 
+
+```graphql
+type Mutation {
+  updateUser(input: UpdateUser!): Task
+    @update
+    @inject(context: "user.id", name: "input.tasks.create.*.user_id")
+}
+```
+
 ## @interface
 
 ```graphql

src/Execution/Arguments/ArgumentSet.php

@@ -2,6 +2,8 @@
 
 namespace Nuwave\Lighthouse\Execution\Arguments;
 
+use GraphQL\Error\Error;
+
 class ArgumentSet
 {
     /**
@@ -61,19 +63,42 @@ public function has(string $key): bool
 
     /**
      * Add a value at the dot-separated path.
-     *
-     * Works just like @see \Illuminate\Support\Arr::add().
+     * Asterisks may be used to indicate wildcards.
      *
      * @param  mixed  $value  any value to inject
      */
-    public function addValue(string $path, $value): self
+    public function addValue(string $path, mixed $value): self
     {
         $argumentSet = $this;
         $keys = explode('.', $path);
 
+        self::applyValue($keys, $value, $argumentSet);
+
+        return $this;
+    }
+
+    /**
+     * @param  array<string>  $keys
+     * @param  mixed  $value any value to inject
+     * @param  ArgumentSet  $argumentSet
+     */
+    private static function applyValue(array $keys, $value, ArgumentSet $argumentSet): void
+    {
         while (count($keys) > 1) {
             $key = array_shift($keys);
 
+            if ($key === '*') {
+                if (!is_array($argumentSet)) {
+                    throw new Error('Asterisk `*` must target an array in the list.');
+                }
+
+                foreach ($argumentSet as $argument) {
+                    self::applyValue($keys, $value, $argument);
+                }
+
+                return;
+            }
+
             // If the key doesn't exist at this depth, we will just create an empty ArgumentSet
             // to hold the next value, allowing us to create the ArgumentSet to hold a final
             // value at the correct depth. Then we'll keep digging into the ArgumentSet.
@@ -89,8 +114,6 @@ public function addValue(string $path, $value): self
         $argument = new Argument();
         $argument->value = $value;
         $argumentSet->arguments[array_shift($keys)] = $argument;
-
-        return $this;
     }
 
     /**

src/Schema/Directives/InjectDirective.php

@@ -28,6 +28,7 @@ public static function definition(): string
   The target name of the argument into which the value is injected.
   You can use dot notation to set the value at arbitrary depth
   within the incoming argument.
+  Use an asterisk `*` as a path segment where the value of the argument is a list to be traversed.
   """
   name: String!
 ) repeatable on FIELD_DEFINITION

tests/Integration/Schema/Directives/InjectDirectiveTest.php

@@ -12,7 +12,7 @@ public function testCreateFromInputObjectWithDeepInjection(): void
         $user = factory(User::class)->create();
         $this->be($user);
 
-        $this->schema .= '
+        $this->schema .= /* @lang GraphQL */ '
         type Task {
             id: ID!
             name: String!
@@ -56,4 +56,87 @@ public function testCreateFromInputObjectWithDeepInjection(): void
             ],
         ]);
     }
+
+    public function testCreateFromInputObjectWithWildcardInjection(): void
+    {
+        $user = factory(User::class)->create();
+        $this->be($user);
+
+        $this->schema .= /* @lang GraphQL */ '
+        type Task {
+            id: ID!
+            name: String!
+            user: User @belongsTo
+        }
+
+        type User {
+            id: ID
+            tasks: [Task!] @hasmany
+        }
+
+        type Mutation {
+            updateUser(input: UpdateUserInput @spread): User
+                @update
+                @inject(context: "user.id", name: "tasks.create.*.user_id")
+        }
+
+        input UpdateUserInput {
+            id: ID!
+            tasks: CreateTaskInputMany
+        }
+
+        input CreateTaskInputMany {
+            create: [CreateTaskInput!]
+        }
+
+        input CreateTaskInput {
+            name: String
+        }
+        ';
+
+        $this->graphQL('
+        mutation ($input: UpdateUserInput!) {
+            updateUser(input: $input) {
+                tasks {
+                    id
+                    name
+                    user {
+                        id
+                    }
+                }
+            }
+        }
+        ', [
+            'input' => [
+                'id' => $user->getKey(),
+                'tasks' => [
+                    'create' => [
+                        [ 'name' => 'foo' ],
+                        [ 'name' => 'bar' ],
+                    ],
+                ],
+            ],
+        ])->assertJson([
+            'data' => [
+                'updateUser' => [
+                    'tasks' => [
+                        [
+                            'id' => '1',
+                            'name' => 'foo',
+                            'user' => [
+                                'id' => '1',
+                            ],
+                        ],
+                        [
+                            'id' => '2',
+                            'name' => 'bar',
+                            'user' => [
+                                'id' => '1',
+                            ],
+                        ],
+                    ],
+                ],
+            ],
+        ]);
+    }
 }