Migration: Enforce NOT NULL and remove default on mail_attachments.created_at

This migration updates the mail_attachments table to require a non-null created_at timestamp for all attachments and removes any default value. This ensures that every attachment record must have an explicit creation time set by the application, preventing issues with zero or missing timestamps and enabling reliable cleanup of old data.

Author: dhairyajangir

lib/Migration/Version5007Date20251019000000.php

@@ -0,0 +1,45 @@
+<?php
+
+declare(strict_types=1);
+
+/**
+ * SPDX-FileCopyrightText: 2025 Nextcloud GmbH and Nextcloud contributors
+ * SPDX-License-Identifier: AGPL-3.0-only
+ */
+
+namespace OCA\Mail\Migration;
+
+use Closure;
+use OCP\DB\ISchemaWrapper;
+use OCP\Migration\IOutput;
+use OCP\Migration\SimpleMigrationStep;
+
+class Version5007Date20251019000000 extends SimpleMigrationStep {
+    /**
+     * @param IOutput $output
+     * @param Closure $schemaClosure The `\Closure` returns a `ISchemaWrapper`
+     * @param array $options
+     * @return null|ISchemaWrapper
+     */
+    #[\Override]
+    public function changeSchema(IOutput $output, Closure $schemaClosure, array $options): ?ISchemaWrapper {
+        /** @var ISchemaWrapper $schema */
+        $schema = $schemaClosure();
+
+        if (!$schema->hasTable('mail_attachments')) {
+            return $schema;
+        }
+
+        $attachments = $schema->getTable('mail_attachments');
+
+        // Ensure created_at is NOT NULL and has no default, so app must set it.
+        if ($attachments->hasColumn('created_at')) {
+            $attachments->changeColumn('created_at', [
+                'notnull' => true,
+                'default' => null,
+            ]);
+        }
+
+        return $schema;
+    }
+}

lib/Service/Attachment/AttachmentService.php

@@ -27,6 +27,7 @@
 use OCP\Files\NotFoundException;
 use OCP\Files\NotPermittedException;
 use Psr\Log\LoggerInterface;
+use OCP\AppFramework\Utility\ITimeFactory;
 
 class AttachmentService implements IAttachmentService {
 	/** @var LocalAttachmentMapper */
@@ -52,6 +53,11 @@ class AttachmentService implements IAttachmentService {
 	 */
 	private $logger;
 
+	/**
+	 * @var ITimeFactory
+	 */
+	private $timeFactory;
+
 	/**
 	 * @param Folder $userFolder
 	 */
@@ -60,13 +66,15 @@ public function __construct($userFolder,
 		AttachmentStorage $storage,
 		IMailManager $mailManager,
 		MessageMapper $imapMessageMapper,
-		LoggerInterface $logger) {
+		LoggerInterface $logger,
+		ITimeFactory $timeFactory) {
 		$this->mapper = $mapper;
 		$this->storage = $storage;
 		$this->mailManager = $mailManager;
 		$this->messageMapper = $imapMessageMapper;
 		$this->userFolder = $userFolder;
 		$this->logger = $logger;
+		$this->timeFactory = $timeFactory;
 	}
 
 	/**
@@ -80,6 +88,8 @@ public function addFile(string $userId, UploadedFile $file): LocalAttachment {
 		$attachment->setUserId($userId);
 		$attachment->setFileName($file->getFileName());
 		$attachment->setMimeType($file->getMimeType());
+        // set createdAt timestamp for cleanup/retention
+        $attachment->setCreatedAt($this->timeFactory->getTime());
 
 		$persisted = $this->mapper->insert($attachment);
 		try {
@@ -98,6 +108,8 @@ public function addFileFromString(string $userId, string $name, string $mime, st
 		$attachment->setUserId($userId);
 		$attachment->setFileName($name);
 		$attachment->setMimeType($mime);
+        // set createdAt timestamp for consistency with uploaded attachments
+        $attachment->setCreatedAt($this->timeFactory->getTime());
 
 		$persisted = $this->mapper->insert($attachment);
 		try {

tests/Unit/Service/Attachment/AttachmentServiceTest.php

@@ -24,6 +24,7 @@
 use OCA\Mail\Service\Attachment\AttachmentStorage;
 use OCA\Mail\Service\Attachment\UploadedFile;
 use OCP\AppFramework\Db\DoesNotExistException;
+use OCP\AppFramework\Utility\ITimeFactory;
 use OCP\Files\Folder;
 use OCP\Files\NotPermittedException;
 use OCP\Share\IAttributes;
@@ -53,6 +54,9 @@ class AttachmentServiceTest extends TestCase {
 	/** @var MockObject|LoggerInterface */
 	private $logger;
 
+	/** @var ITimeFactory|MockObject */
+	private $timeFactory;
+
 	protected function setUp(): void {
 		parent::setUp();
 
@@ -62,14 +66,17 @@ protected function setUp(): void {
 		$this->messageMapper = $this->createMock(MessageMapper::class);
 		$this->userFolder = $this->createMock(Folder::class);
 		$this->logger = $this->createMock(LoggerInterface::class);
+		$this->timeFactory = $this->createMock(ITimeFactory::class);
+		$this->timeFactory->method('getTime')->willReturn(123456);
 
 		$this->service = new AttachmentService(
 			$this->userFolder,
 			$this->mapper,
 			$this->storage,
 			$this->mailManager,
 			$this->messageMapper,
-			$this->logger
+			$this->logger,
+			$this->timeFactory
 		);
 	}
 
@@ -82,6 +89,7 @@ public function testAddFileWithUploadException() {
 		$attachment = LocalAttachment::fromParams([
 			'userId' => $userId,
 			'fileName' => 'cat.jpg',
+			'createdAt' => 123456,
 		]);
 		$persistedAttachment = LocalAttachment::fromParams([
 			'id' => 123,
@@ -113,7 +121,8 @@ public function testAddFile() {
 			->willReturn('cat.jpg');
 		$attachment = LocalAttachment::fromParams([
 			'userId' => $userId,
-			'fileName' => 'cat.jpg'
+			'fileName' => 'cat.jpg',
+			'createdAt' => 123456
 		]);
 		$persistedAttachment = LocalAttachment::fromParams([
 			'id' => 123,
@@ -138,6 +147,7 @@ public function testAddFileFromStringWithUploadException() {
 			'userId' => $userId,
 			'fileName' => 'cat.jpg',
 			'mimeType' => 'image/jpg',
+			'createdAt' => 123456,
 		]);
 		$persistedAttachment = LocalAttachment::fromParams([
 			'id' => 123,
@@ -168,6 +178,7 @@ public function testAddFileFromString() {
 			'userId' => $userId,
 			'fileName' => 'cat.jpg',
 			'mimeType' => 'image/jpg',
+			'createdAt' => 123456,
 		]);
 		$persistedAttachment = LocalAttachment::fromParams([
 			'id' => 123,
@@ -283,6 +294,7 @@ public function testHandleAttachmentsForwardedMessageAttachment(): void {
 			'userId' => $userId,
 			'fileName' => 'cat.jpg',
 			'mimeType' => 'text/plain',
+			'createdAt' => 123456,
 		]);
 		$persistedAttachment = LocalAttachment::fromParams([
 			'id' => 123,
@@ -334,6 +346,7 @@ public function testHandleAttachmentsForwardedAttachment(): void {
 			'userId' => $userId,
 			'fileName' => 'cat.jpg',
 			'mimeType' => 'text/plain',
+			'createdAt' => 123456,
 		]);
 		$persistedAttachment = LocalAttachment::fromParams([
 			'id' => 123,