Init client with correct base URL when custom request adapter is used

src/GraphServiceClient.php

@@ -51,18 +51,20 @@ public function __construct(
     /**
      * Get an instance of GraphServiceClient that uses $requestAdapter
      * @param RequestAdapter $requestAdapter
-     * @param string $nationalCloud Defaults to https://graph.microsoft.com. See
-     * https://learn.microsoft.com/en-us/graph/deployments
+     * @param string $nationalCloud Sets $requestAdapter baseURL if none has already been set
+     * Defaults to https://graph.microsoft.com. See https://learn.microsoft.com/en-us/graph/deployments
      * @return GraphServiceClient
      */
     public static function createWithRequestAdapter(
         RequestAdapter $requestAdapter,
         string $nationalCloud = NationalCloud::GLOBAL
     ): GraphServiceClient
     {
-        $requestAdapter->setBaseUrl($nationalCloud);
+        if (!$requestAdapter->getBaseUrl()) {
+            $requestAdapter->setBaseUrl("$nationalCloud/beta");
+        }
         $placeholder = new ClientCredentialContext('tenant', 'client', 'secret');
-        return new GraphServiceClient($placeholder, [], $nationalCloud, $requestAdapter);
+        return new GraphServiceClient($placeholder, [], 'placeholder', $requestAdapter);
     }
 
     /**

tests/GraphServiceClientTest.php

@@ -3,6 +3,7 @@
 namespace Microsoft\Graph\Beta\Test;
 
 use Microsoft\Graph\Beta\GraphServiceClient;
+use Microsoft\Graph\Core\NationalCloud;
 use Microsoft\Kiota\Abstractions\Authentication\AnonymousAuthenticationProvider;
 use Microsoft\Kiota\Authentication\Oauth\ClientCredentialContext;
 use Microsoft\Kiota\Http\GuzzleRequestAdapter;
@@ -20,4 +21,23 @@ public function testsInit(): void
         $client = new GraphServiceClient($testContext, ['Users.Read']);
         $this->assertInstanceOf(GraphServiceClient::class, $client);
     }
+
+    public function testCorrectDefaultBaseUrlIsSetWhenRequestAdapterHasEmptyBaseUrl(): void
+    {
+        $requestAdapter = new GuzzleRequestAdapter(new AnonymousAuthenticationProvider());
+        $client = GraphServiceClient::createWithRequestAdapter($requestAdapter);
+        $this->assertEquals(NationalCloud::GLOBAL.'/beta', $client->getRequestAdapter()->getBaseUrl());
+
+        $requestAdapter = new GuzzleRequestAdapter(new AnonymousAuthenticationProvider());
+        $client = GraphServiceClient::createWithRequestAdapter($requestAdapter, NationalCloud::CHINA);
+        $this->assertEquals(NationalCloud::CHINA.'/beta', $client->getRequestAdapter()->getBaseUrl());
+    }
+
+    public function testCustomBaseUrlIsNotOverriden(): void
+    {
+        $requestAdapter = new GuzzleRequestAdapter(new AnonymousAuthenticationProvider());
+        $requestAdapter->setBaseUrl(NationalCloud::CHINA);
+        $client = GraphServiceClient::createWithRequestAdapter($requestAdapter, NationalCloud::US_DOD);
+        $this->assertEquals(NationalCloud::CHINA, $client->getRequestAdapter()->getBaseUrl());
+    }
 }