feat: add interface method annotation

build/ClientAnnotator.php

@@ -6,19 +6,33 @@ class ClientAnnotator
 {
     /** @var ReflectionClass */
     private $reflection;
+
+    /** @var ReflectionClass|null */
+    private $reflectionInterface;
+
     /** @var string */
     private $endpoint;
+
     /** @var string[] */
     private $versions;
+
     /** @var array */
     private $methods;
+
     /** @var array */
     private $aliases;
 
 
     public function __construct($clientClassName)
     {
         $this->reflection = new ReflectionClass($clientClassName);
+        $this->reflectionInterface = null;
+        // Check if client has an interface
+        $interfaceName = $clientClassName . 'Interface';
+        if (interface_exists($interfaceName)) {
+            $this->reflectionInterface = new ReflectionClass($interfaceName);
+        }
+
         $this->aliases = \Aws\load_compiled_json(__DIR__ . '/../src/data/aliases.json');
     }
 
@@ -36,6 +50,17 @@ public function updateApiMethodAnnotations()
             '/^\* @method (\\\\Aws\\\\Result|\\\\GuzzleHttp\\\\Promise\\\\Promise) /'
         );
 
+        if ($this->reflectionInterface !== null) {
+            $interfaceUpdater = new ClassAnnotationUpdater(
+                $this->reflectionInterface,
+                $this->getMethodAnnotations(),
+                $this->getDefaultDocComment(),
+                '/^\* @method (\\\\Aws\\\\Result|\\\\GuzzleHttp\\\\Promise\\\\Promise) /'
+            );
+
+            return $interfaceUpdater->update() && $updater->update();
+        }
+
         return $updater->update();
     }