feat: setup appdata folder based on config value

RUN patch -u ${BASE_DIR}/lib/private/Security/VerificationToken/VerificationToken.php -i ${TMP_PATCH_DIR}/033-verification-token-private.patch

RUN patch -u ${BASE_DIR}/lib/private/AppFramework/Middleware/Security/CORSMiddleware.php -i ${TMP_PATCH_DIR}/034-oidc-bearer-token-auth.patch

#RUN patch -u ${BASE_DIR}/custom_apps/snappymail/app/snappymail/v/2.38.2+murena-20251112/app/libraries/RainLoop/Actions/Contacts.php -i ${TMP_PATCH_DIR}/037-snappymail-contact.patch

RUN cd ${BASE_DIR} && patch -p0 < ${TMP_PATCH_DIR}/038-appdata-folder-based-on-config.patch

RUN rm -rf ${TMP_PATCH_DIR}

diff --git a/config/config.sample.php b/config/config.sample.php

index 82acd43e9d9..5620c3c0156 100644

--- a/config/config.sample.php

+++ b/config/config.sample.php

@@ -2291,6 +2291,15 @@ $CONFIG = [

 	 */

 	'updatedirectory' => '',

+	/**

+ 	* Override where Nextcloud stores the ``appdata_INSTANCEID`` directory. Useful

+ 	* when using remote object storage where local system disks provide faster data

+ 	* access. Defaults to `datadirectory` if unset.

+ 	*

+ 	* The Web server user must have write access to this directory.

+ 	*/

+	'appdatadirectory' => '',

+

 	/**

 	 * Block specific files or filenames, disallowing uploads or access (read and write).

 	 * ``.htaccess`` is blocked by default.

diff --git a/lib/private/Files/SetupManager.php b/lib/private/Files/SetupManager.php

index e058be0663b..fb8fb01d69a 100644

--- a/lib/private/Files/SetupManager.php

+++ b/lib/private/Files/SetupManager.php

@@ -429,10 +429,26 @@ class SetupManager implements ISetupManager {

 		foreach ($rootMounts as $rootMountProvider) {

 			$this->mountManager->addMount($rootMountProvider);

 		}

-

+		$this->setupAppData();

 		$this->eventLogger->end('fs:setup:root');

 	}

+	private function setupAppData(): void {

+		if ($appdatadirectory = $this->config->getSystemValue('appdatadirectory', null)) {

+			$instanceId = $this->config->getSystemValue('instanceid', null);

+			if ($instanceId === null) {

+				throw new \RuntimeException('no instance id!');

+			}

+			$folderName = 'appdata_' . $instanceId;

+			$arguments = [

+				'datadir' => $appdatadirectory,

+			];

+			$storage = new \OC\Files\Storage\Local($arguments);

+			$mount = new \OC\Files\Mount\MountPoint($storage, $folderName, $arguments);

+			$this->mountManager->addMount($mount);

+		}

+	}

+

 	/**

 	 * Get the user to setup for a path or `null` if the root needs to be setup

 	 *

diff --git a/lib/private/SystemConfig.php b/lib/private/SystemConfig.php

index 7e8946f4d05..b59b979d7b5 100644

--- a/lib/private/SystemConfig.php

+++ b/lib/private/SystemConfig.php

@@ -20,6 +20,7 @@ class SystemConfig {

 	protected const DEFAULT_SENSITIVE_VALUES = [

 		'instanceid' => true,

 		'datadirectory' => true,

+		'appdatadirectory' => true,

 		'dbname' => true,

 		'dbhost' => true,

 		'dbpassword' => true,