feat(upgrade): migration attributes

Signed-off-by: Maxence Lange <maxence@artificial-owl.com>

21 files changed, 1138 insertions, 0 deletions

diff --git a/core/Command/Db/Migrations/PreviewCommand.php b/core/Command/Db/Migrations/PreviewCommand.php
new file mode 100644
index 00000000000..6440ed5835c
--- /dev/null
+++ b/core/Command/Db/Migrations/PreviewCommand.php
@@ -0,0 +1,102 @@
+<?php
+
+declare(strict_types=1);
+
+/**
+ * SPDX-FileCopyrightText: 2024 Nextcloud GmbH and Nextcloud contributors
+ * SPDX-License-Identifier: AGPL-3.0-or-later
+ */
+namespace OC\Core\Command\Db\Migrations;
+
+use OC\Migration\MetadataManager;
+use OC\Updater\ReleaseMetadata;
+use OCP\Migration\Attributes\MigrationAttribute;
+use Symfony\Component\Console\Command\Command;
+use Symfony\Component\Console\Helper\Table;
+use Symfony\Component\Console\Helper\TableCell;
+use Symfony\Component\Console\Helper\TableCellStyle;
+use Symfony\Component\Console\Helper\TableSeparator;
+use Symfony\Component\Console\Input\InputArgument;
+use Symfony\Component\Console\Input\InputInterface;
+use Symfony\Component\Console\Output\OutputInterface;
+
+/**
+ * @since 30.0.0
+ */
+class PreviewCommand extends Command {
+	private bool $initiated = false;
+	public function __construct(
+		private MetadataManager $metadataManager,
+		private ReleaseMetadata $releaseMetadata,
+	) {
+		parent::__construct();
+	}
+
+	protected function configure(): void {
+		$this
+			->setName('migrations:preview')
+			->setDescription('Get preview of available DB migrations in case of initiating an upgrade')
+			->addArgument('version', InputArgument::REQUIRED, 'The destination version number');
+
+		parent::configure();
+	}
+
+	public function execute(InputInterface $input, OutputInterface $output): int {
+		$version = $input->getArgument('version');
+		if (filter_var($version, FILTER_VALIDATE_URL)) {
+			$metadata = $this->releaseMetadata->downloadMetadata($version);
+		} elseif (str_starts_with($version, '/')) {
+			$metadata = json_decode(file_get_contents($version), true, flags: JSON_THROW_ON_ERROR);
+		} else {
+			$metadata = $this->releaseMetadata->getMetadata($version);
+		}
+
+		$parsed = $this->metadataManager->getMigrationsAttributesFromReleaseMetadata($metadata['migrations'] ?? [], true);
+
+		$table = new Table($output);
+		$this->displayMigrations($table, 'core', $parsed['core'] ?? []);
+		foreach ($parsed['apps'] as $appId => $migrations) {
+			if (!empty($migrations)) {
+				$this->displayMigrations($table, $appId, $migrations);
+			}
+		}
+		$table->render();
+
+		return 0;
+	}
+
+	private function displayMigrations(Table $table, string $appId, array $data): void {
+		if (empty($data)) {
+			return;
+		}
+
+		if ($this->initiated) {
+			$table->addRow(new TableSeparator());
+		}
+		$this->initiated = true;
+
+		$table->addRow(
+			[
+				new TableCell(
+					$appId,
+					[
+						'colspan' => 2,
+						'style' => new TableCellStyle(['cellFormat' => '<info>%s</info>'])
+					]
+				)
+			]
+		)->addRow(new TableSeparator());
+
+		/** @var MigrationAttribute[] $attributes */
+		foreach($data as $migration => $attributes) {
+			$attributesStr = [];
+			foreach($attributes as $attribute) {
+				$definition = '<info>' . $attribute->definition() . "</info>";
+				$definition .= empty($attribute->getDescription()) ? '' : "\n  " . $attribute->getDescription();
+				$definition .= empty($attribute->getNotes()) ? '' : "\n  <comment>" . implode("</comment>\n  <comment>", $attribute->getNotes()) . '</comment>';
+				$attributesStr[] = $definition;
+			}
+			$table->addRow([$migration, implode("\n", $attributesStr)]);
+		}
+	}
+}
diff --git a/core/register_command.php b/core/register_command.php
index 4a84e551ce0..6d1abb52fea 100644
--- a/core/register_command.php
+++ b/core/register_command.php
@@ -110,6 +110,7 @@ if ($config->getSystemValueBool('installed', false)) {
 	$application->add(Server::get(Command\Db\AddMissingIndices::class));
 	$application->add(Server::get(Command\Db\AddMissingPrimaryKeys::class));
 
+	$application->add(Server::get(Command\Db\Migrations\PreviewCommand::class));
 	if ($config->getSystemValueBool('debug', false)) {
 		$application->add(Server::get(Command\Db\Migrations\StatusCommand::class));
 		$application->add(Server::get(Command\Db\Migrations\MigrateCommand::class));
diff --git a/lib/composer/composer/autoload_classmap.php b/lib/composer/composer/autoload_classmap.php
index 6defb0f12fb..a09bbb25038 100644
--- a/lib/composer/composer/autoload_classmap.php
+++ b/lib/composer/composer/autoload_classmap.php
@@ -555,6 +555,18 @@ return array(
     'OCP\\Mail\\IEMailTemplate' => $baseDir . '/lib/public/Mail/IEMailTemplate.php',
     'OCP\\Mail\\IMailer' => $baseDir . '/lib/public/Mail/IMailer.php',
     'OCP\\Mail\\IMessage' => $baseDir . '/lib/public/Mail/IMessage.php',
+    'OCP\\Migration\\Attributes\\AddColumn' => $baseDir . '/lib/public/Migration/Attributes/AddColumn.php',
+    'OCP\\Migration\\Attributes\\AddIndex' => $baseDir . '/lib/public/Migration/Attributes/AddIndex.php',
+    'OCP\\Migration\\Attributes\\ColumnMigrationAttribute' => $baseDir . '/lib/public/Migration/Attributes/ColumnMigrationAttribute.php',
+    'OCP\\Migration\\Attributes\\CreateTable' => $baseDir . '/lib/public/Migration/Attributes/CreateTable.php',
+    'OCP\\Migration\\Attributes\\DropColumn' => $baseDir . '/lib/public/Migration/Attributes/DropColumn.php',
+    'OCP\\Migration\\Attributes\\DropIndex' => $baseDir . '/lib/public/Migration/Attributes/DropIndex.php',
+    'OCP\\Migration\\Attributes\\DropTable' => $baseDir . '/lib/public/Migration/Attributes/DropTable.php',
+    'OCP\\Migration\\Attributes\\GenericMigrationAttribute' => $baseDir . '/lib/public/Migration/Attributes/GenericMigrationAttribute.php',
+    'OCP\\Migration\\Attributes\\IndexMigrationAttribute' => $baseDir . '/lib/public/Migration/Attributes/IndexMigrationAttribute.php',
+    'OCP\\Migration\\Attributes\\MigrationAttribute' => $baseDir . '/lib/public/Migration/Attributes/MigrationAttribute.php',
+    'OCP\\Migration\\Attributes\\ModifyColumn' => $baseDir . '/lib/public/Migration/Attributes/ModifyColumn.php',
+    'OCP\\Migration\\Attributes\\TableMigrationAttribute' => $baseDir . '/lib/public/Migration/Attributes/TableMigrationAttribute.php',
     'OCP\\Migration\\BigIntMigration' => $baseDir . '/lib/public/Migration/BigIntMigration.php',
     'OCP\\Migration\\IMigrationStep' => $baseDir . '/lib/public/Migration/IMigrationStep.php',
     'OCP\\Migration\\IOutput' => $baseDir . '/lib/public/Migration/IOutput.php',
@@ -1071,6 +1083,7 @@ return array(
     'OC\\Core\\Command\\Db\\Migrations\\ExecuteCommand' => $baseDir . '/core/Command/Db/Migrations/ExecuteCommand.php',
     'OC\\Core\\Command\\Db\\Migrations\\GenerateCommand' => $baseDir . '/core/Command/Db/Migrations/GenerateCommand.php',
     'OC\\Core\\Command\\Db\\Migrations\\MigrateCommand' => $baseDir . '/core/Command/Db/Migrations/MigrateCommand.php',
+    'OC\\Core\\Command\\Db\\Migrations\\PreviewCommand' => $baseDir . '/core/Command/Db/Migrations/PreviewCommand.php',
     'OC\\Core\\Command\\Db\\Migrations\\StatusCommand' => $baseDir . '/core/Command/Db/Migrations/StatusCommand.php',
     'OC\\Core\\Command\\Encryption\\ChangeKeyStorageRoot' => $baseDir . '/core/Command/Encryption/ChangeKeyStorageRoot.php',
     'OC\\Core\\Command\\Encryption\\DecryptAll' => $baseDir . '/core/Command/Encryption/DecryptAll.php',
@@ -1565,6 +1578,8 @@ return array(
     'OC\\MemoryInfo' => $baseDir . '/lib/private/MemoryInfo.php',
     'OC\\Migration\\BackgroundRepair' => $baseDir . '/lib/private/Migration/BackgroundRepair.php',
     'OC\\Migration\\ConsoleOutput' => $baseDir . '/lib/private/Migration/ConsoleOutput.php',
+    'OC\\Migration\\Exceptions\\AttributeException' => $baseDir . '/lib/private/Migration/Exceptions/AttributeException.php',
+    'OC\\Migration\\MetadataManager' => $baseDir . '/lib/private/Migration/MetadataManager.php',
     'OC\\Migration\\NullOutput' => $baseDir . '/lib/private/Migration/NullOutput.php',
     'OC\\Migration\\SimpleOutput' => $baseDir . '/lib/private/Migration/SimpleOutput.php',
     'OC\\NaturalSort' => $baseDir . '/lib/private/NaturalSort.php',
@@ -1844,6 +1859,8 @@ return array(
     'OC\\Updater\\Changes' => $baseDir . '/lib/private/Updater/Changes.php',
     'OC\\Updater\\ChangesCheck' => $baseDir . '/lib/private/Updater/ChangesCheck.php',
     'OC\\Updater\\ChangesMapper' => $baseDir . '/lib/private/Updater/ChangesMapper.php',
+    'OC\\Updater\\Exceptions\\ReleaseMetadataException' => $baseDir . '/lib/private/Updater/Exceptions/ReleaseMetadataException.php',
+    'OC\\Updater\\ReleaseMetadata' => $baseDir . '/lib/private/Updater/ReleaseMetadata.php',
     'OC\\Updater\\VersionCheck' => $baseDir . '/lib/private/Updater/VersionCheck.php',
     'OC\\UserStatus\\ISettableProvider' => $baseDir . '/lib/private/UserStatus/ISettableProvider.php',
     'OC\\UserStatus\\Manager' => $baseDir . '/lib/private/UserStatus/Manager.php',
diff --git a/lib/composer/composer/autoload_static.php b/lib/composer/composer/autoload_static.php
index db8baeb6341..16fb699964c 100644
--- a/lib/composer/composer/autoload_static.php
+++ b/lib/composer/composer/autoload_static.php
@@ -588,6 +588,18 @@ class ComposerStaticInit749170dad3f5e7f9ca158f5a9f04f6a2
         'OCP\\Mail\\IEMailTemplate' => __DIR__ . '/../../..' . '/lib/public/Mail/IEMailTemplate.php',
         'OCP\\Mail\\IMailer' => __DIR__ . '/../../..' . '/lib/public/Mail/IMailer.php',
         'OCP\\Mail\\IMessage' => __DIR__ . '/../../..' . '/lib/public/Mail/IMessage.php',
+        'OCP\\Migration\\Attributes\\AddColumn' => __DIR__ . '/../../..' . '/lib/public/Migration/Attributes/AddColumn.php',
+        'OCP\\Migration\\Attributes\\AddIndex' => __DIR__ . '/../../..' . '/lib/public/Migration/Attributes/AddIndex.php',
+        'OCP\\Migration\\Attributes\\ColumnMigrationAttribute' => __DIR__ . '/../../..' . '/lib/public/Migration/Attributes/ColumnMigrationAttribute.php',
+        'OCP\\Migration\\Attributes\\CreateTable' => __DIR__ . '/../../..' . '/lib/public/Migration/Attributes/CreateTable.php',
+        'OCP\\Migration\\Attributes\\DropColumn' => __DIR__ . '/../../..' . '/lib/public/Migration/Attributes/DropColumn.php',
+        'OCP\\Migration\\Attributes\\DropIndex' => __DIR__ . '/../../..' . '/lib/public/Migration/Attributes/DropIndex.php',
+        'OCP\\Migration\\Attributes\\DropTable' => __DIR__ . '/../../..' . '/lib/public/Migration/Attributes/DropTable.php',
+        'OCP\\Migration\\Attributes\\GenericMigrationAttribute' => __DIR__ . '/../../..' . '/lib/public/Migration/Attributes/GenericMigrationAttribute.php',
+        'OCP\\Migration\\Attributes\\IndexMigrationAttribute' => __DIR__ . '/../../..' . '/lib/public/Migration/Attributes/IndexMigrationAttribute.php',
+        'OCP\\Migration\\Attributes\\MigrationAttribute' => __DIR__ . '/../../..' . '/lib/public/Migration/Attributes/MigrationAttribute.php',
+        'OCP\\Migration\\Attributes\\ModifyColumn' => __DIR__ . '/../../..' . '/lib/public/Migration/Attributes/ModifyColumn.php',
+        'OCP\\Migration\\Attributes\\TableMigrationAttribute' => __DIR__ . '/../../..' . '/lib/public/Migration/Attributes/TableMigrationAttribute.php',
         'OCP\\Migration\\BigIntMigration' => __DIR__ . '/../../..' . '/lib/public/Migration/BigIntMigration.php',
         'OCP\\Migration\\IMigrationStep' => __DIR__ . '/../../..' . '/lib/public/Migration/IMigrationStep.php',
         'OCP\\Migration\\IOutput' => __DIR__ . '/../../..' . '/lib/public/Migration/IOutput.php',
@@ -1104,6 +1116,7 @@ class ComposerStaticInit749170dad3f5e7f9ca158f5a9f04f6a2
         'OC\\Core\\Command\\Db\\Migrations\\ExecuteCommand' => __DIR__ . '/../../..' . '/core/Command/Db/Migrations/ExecuteCommand.php',
         'OC\\Core\\Command\\Db\\Migrations\\GenerateCommand' => __DIR__ . '/../../..' . '/core/Command/Db/Migrations/GenerateCommand.php',
         'OC\\Core\\Command\\Db\\Migrations\\MigrateCommand' => __DIR__ . '/../../..' . '/core/Command/Db/Migrations/MigrateCommand.php',
+        'OC\\Core\\Command\\Db\\Migrations\\PreviewCommand' => __DIR__ . '/../../..' . '/core/Command/Db/Migrations/PreviewCommand.php',
         'OC\\Core\\Command\\Db\\Migrations\\StatusCommand' => __DIR__ . '/../../..' . '/core/Command/Db/Migrations/StatusCommand.php',
         'OC\\Core\\Command\\Encryption\\ChangeKeyStorageRoot' => __DIR__ . '/../../..' . '/core/Command/Encryption/ChangeKeyStorageRoot.php',
         'OC\\Core\\Command\\Encryption\\DecryptAll' => __DIR__ . '/../../..' . '/core/Command/Encryption/DecryptAll.php',
@@ -1598,6 +1611,8 @@ class ComposerStaticInit749170dad3f5e7f9ca158f5a9f04f6a2
         'OC\\MemoryInfo' => __DIR__ . '/../../..' . '/lib/private/MemoryInfo.php',
         'OC\\Migration\\BackgroundRepair' => __DIR__ . '/../../..' . '/lib/private/Migration/BackgroundRepair.php',
         'OC\\Migration\\ConsoleOutput' => __DIR__ . '/../../..' . '/lib/private/Migration/ConsoleOutput.php',
+        'OC\\Migration\\Exceptions\\AttributeException' => __DIR__ . '/../../..' . '/lib/private/Migration/Exceptions/AttributeException.php',
+        'OC\\Migration\\MetadataManager' => __DIR__ . '/../../..' . '/lib/private/Migration/MetadataManager.php',
         'OC\\Migration\\NullOutput' => __DIR__ . '/../../..' . '/lib/private/Migration/NullOutput.php',
         'OC\\Migration\\SimpleOutput' => __DIR__ . '/../../..' . '/lib/private/Migration/SimpleOutput.php',
         'OC\\NaturalSort' => __DIR__ . '/../../..' . '/lib/private/NaturalSort.php',
@@ -1877,6 +1892,8 @@ class ComposerStaticInit749170dad3f5e7f9ca158f5a9f04f6a2
         'OC\\Updater\\Changes' => __DIR__ . '/../../..' . '/lib/private/Updater/Changes.php',
         'OC\\Updater\\ChangesCheck' => __DIR__ . '/../../..' . '/lib/private/Updater/ChangesCheck.php',
         'OC\\Updater\\ChangesMapper' => __DIR__ . '/../../..' . '/lib/private/Updater/ChangesMapper.php',
+        'OC\\Updater\\Exceptions\\ReleaseMetadataException' => __DIR__ . '/../../..' . '/lib/private/Updater/Exceptions/ReleaseMetadataException.php',
+        'OC\\Updater\\ReleaseMetadata' => __DIR__ . '/../../..' . '/lib/private/Updater/ReleaseMetadata.php',
         'OC\\Updater\\VersionCheck' => __DIR__ . '/../../..' . '/lib/private/Updater/VersionCheck.php',
         'OC\\UserStatus\\ISettableProvider' => __DIR__ . '/../../..' . '/lib/private/UserStatus/ISettableProvider.php',
         'OC\\UserStatus\\Manager' => __DIR__ . '/../../..' . '/lib/private/UserStatus/Manager.php',
diff --git a/lib/private/Migration/Exceptions/AttributeException.php b/lib/private/Migration/Exceptions/AttributeException.php
new file mode 100644
index 00000000000..3daf99032ad
--- /dev/null
+++ b/lib/private/Migration/Exceptions/AttributeException.php
@@ -0,0 +1,17 @@
+<?php
+
+declare(strict_types=1);
+
+/**
+ * SPDX-FileCopyrightText: 2024 Nextcloud GmbH and Nextcloud contributors
+ * SPDX-License-Identifier: AGPL-3.0-or-later
+ */
+namespace OC\Migration\Exceptions;
+
+use Exception;
+
+/**
+ * @since 30.0.0
+ */
+class AttributeException extends Exception {
+}
diff --git a/lib/private/Migration/MetadataManager.php b/lib/private/Migration/MetadataManager.php
new file mode 100644
index 00000000000..cf569755ecd
--- /dev/null
+++ b/lib/private/Migration/MetadataManager.php
@@ -0,0 +1,127 @@
+<?php
+
+declare(strict_types=1);
+
+/**
+ * SPDX-FileCopyrightText: 2024 Nextcloud GmbH and Nextcloud contributors
+ * SPDX-License-Identifier: AGPL-3.0-only
+ */
+namespace OC\Migration;
+
+use OC\DB\Connection;
+use OC\DB\MigrationService;
+use OC\Migration\Exceptions\AttributeException;
+use OCP\App\IAppManager;
+use OCP\Migration\Attributes\GenericMigrationAttribute;
+use OCP\Migration\Attributes\MigrationAttribute;
+use Psr\Log\LoggerInterface;
+
+/**
+ * Helps managing DB Migrations' Metadata
+ *
+ * @since 30.0.0
+ */
+class MetadataManager {
+	public function __construct(
+		private IAppManager $appManager,
+		private Connection $connection,
+		private LoggerInterface $logger,
+	) {
+	}
+
+	/**
+	 * convert direct data from release metadata into a list of Migrations' Attribute
+	 *
+	 * @param array<array-key, array<array-key, array>> $metadata
+	 * @param bool $filterKnownMigrations ignore metadata already done in local instance
+	 *
+	 * @return array{apps: array<array-key, array<string, MigrationAttribute[]>>, core: array<string, MigrationAttribute[]>}
+	 * @since 30.0.0
+	 */
+	public function getMigrationsAttributesFromReleaseMetadata(
+		array $metadata,
+		bool $filterKnownMigrations = false
+	): array {
+		$appsAttributes = [];
+		foreach (array_keys($metadata['apps']) as $appId) {
+			if ($filterKnownMigrations && !$this->appManager->isInstalled($appId)) {
+				continue; // if not interested and app is not installed
+			}
+
+			$done = ($filterKnownMigrations) ? $this->getKnownMigrations($appId) : [];
+			$appsAttributes[$appId] = $this->parseMigrations($metadata['apps'][$appId] ?? [], $done);
+		}
+
+		$done = ($filterKnownMigrations) ? $this->getKnownMigrations('core') : [];
+		return [
+			'core' => $this->parseMigrations($metadata['core'] ?? [], $done),
+			'apps' => $appsAttributes
+		];
+	}
+
+	/**
+	 * convert raw data to a list of MigrationAttribute
+	 *
+	 * @param array $migrations
+	 * @param array $ignoreMigrations
+	 *
+	 * @return array<string, MigrationAttribute[]>
+	 */
+	private function parseMigrations(array $migrations, array $ignoreMigrations = []): array {
+		$parsed = [];
+		foreach (array_keys($migrations) as $entry) {
+			if (in_array($entry, $ignoreMigrations)) {
+				continue;
+			}
+
+			$parsed[$entry] = [];
+			foreach ($migrations[$entry] as $item) {
+				try {
+					$parsed[$entry][] = $this->createAttribute($item);
+				} catch (AttributeException $e) {
+					$this->logger->warning('exception while trying to create attribute', ['exception' => $e, 'item' => json_encode($item)]);
+					$parsed[$entry][] = new GenericMigrationAttribute($item);
+				}
+			}
+		}
+
+		return $parsed;
+	}
+
+	/**
+	 * returns migrations already done
+	 *
+	 * @param string $appId
+	 *
+	 * @return array
+	 * @throws \Exception
+	 */
+	private function getKnownMigrations(string $appId): array {
+		$ms = new MigrationService($appId, $this->connection);
+		return $ms->getMigratedVersions();
+	}
+
+	/**
+	 * generate (deserialize) a MigrationAttribute from a serialized version
+	 *
+	 * @param array $item
+	 *
+	 * @return MigrationAttribute
+	 * @throws AttributeException
+	 */
+	private function createAttribute(array $item): MigrationAttribute {
+		$class = $item['class'] ?? '';
+		$namespace = 'OCP\Migration\Attributes\\';
+		if (!str_starts_with($class, $namespace)
+			|| !ctype_alpha(substr($class, strlen($namespace)))) {
+			throw new AttributeException('class name does not looks valid');
+		}
+
+		try {
+			$attribute = new $class($item['table'] ?? '');
+			return $attribute->import($item);
+		} catch (\Error) {
+			throw new AttributeException('cannot import Attribute');
+		}
+	}
+}
diff --git a/lib/private/Updater/Exceptions/ReleaseMetadataException.php b/lib/private/Updater/Exceptions/ReleaseMetadataException.php
new file mode 100644
index 00000000000..bc82e4e03df
--- /dev/null
+++ b/lib/private/Updater/Exceptions/ReleaseMetadataException.php
@@ -0,0 +1,17 @@
+<?php
+
+declare(strict_types=1);
+
+/**
+ * SPDX-FileCopyrightText: 2024 Nextcloud GmbH and Nextcloud contributors
+ * SPDX-License-Identifier: AGPL-3.0-or-later
+ */
+namespace OC\Updater\Exceptions;
+
+use Exception;
+
+/**
+ * @since 30.0.0
+ */
+class ReleaseMetadataException extends Exception {
+}
diff --git a/lib/private/Updater/ReleaseMetadata.php b/lib/private/Updater/ReleaseMetadata.php
new file mode 100644
index 00000000000..4596d1d3fb7
--- /dev/null
+++ b/lib/private/Updater/ReleaseMetadata.php
@@ -0,0 +1,79 @@
+<?php
+
+declare(strict_types=1);
+
+/**
+ * SPDX-FileCopyrightText: 2024 Nextcloud GmbH and Nextcloud contributors
+ * SPDX-License-Identifier: AGPL-3.0-or-later
+ */
+namespace OC\Updater;
+
+use Exception;
+use JsonException;
+use OC\Updater\Exceptions\ReleaseMetadataException;
+use OCP\Http\Client\IClientService;
+
+/** retrieve releases metadata from official servers
+ *
+ * @since 30.0.0
+ */
+class ReleaseMetadata {
+	public function __construct(
+		private IClientService $clientService,
+	) {
+	}
+
+	/**
+	 * returns metadata based on release version
+	 *
+	 * - version is a stable release, metadata is downloaded from official releases folder
+	 * - version is not a table release, metadata is downloaded from official prereleases folder
+	 * - version is a major version (30, 31, 32, ...), latest metadata are downloaded
+	 *
+	 * @param string $version
+	 *
+	 * @return array
+	 * @throws ReleaseMetadataException
+	 * @since 30.0.0
+	 */
+	public function getMetadata(string $version): array {
+		if (!str_contains($version, '.')) {
+			$url = 'https://download.nextcloud.com/server/releases/latest-' . $version . '.metadata';
+		} else {
+			[,,$minor] = explode('.', $version);
+			if (ctype_digit($minor)) {
+				$url = 'https://download.nextcloud.com/server/releases/nextcloud-' . $version . '.metadata';
+			} else {
+				$url = 'https://download.nextcloud.com/server/prereleases/nextcloud-' . $version . '.metadata';
+			}
+		}
+		return $this->downloadMetadata($url);
+	}
+
+	/**
+	 * download Metadata from a link
+	 *
+	 * @param string $url
+	 *
+	 * @return array
+	 * @throws ReleaseMetadataException
+	 * @since 30.0.0
+	 */
+	public function downloadMetadata(string $url): array {
+		$client = $this->clientService->newClient();
+		try {
+			$response = $client->get($url, [
+				'timeout' => 10,
+				'connect_timeout' => 10
+			]);
+		} catch (Exception $e) {
+			throw new ReleaseMetadataException('could not reach metadata at ' . $url, previous: $e);
+		}
+
+		try {
+			return json_decode($response->getBody(), true, flags: JSON_THROW_ON_ERROR);
+		} catch (JsonException) {
+			throw new ReleaseMetadataException('remote document is not valid');
+		}
+	}
+}
diff --git a/lib/public/Migration/Attributes/AddColumn.php b/lib/public/Migration/Attributes/AddColumn.php
new file mode 100644
index 00000000000..3ecae8fde0d
--- /dev/null
+++ b/lib/public/Migration/Attributes/AddColumn.php
@@ -0,0 +1,29 @@
+<?php
+
+declare(strict_types=1);
+
+/**
+ * SPDX-FileCopyrightText: 2024 Nextcloud GmbH and Nextcloud contributors
+ * SPDX-License-Identifier: AGPL-3.0-or-later
+ */
+namespace OCP\Migration\Attributes;
+
+use Attribute;
+
+/**
+ * attribute on new column creation
+ *
+ * @since 30.0.0
+ */
+#[Attribute(Attribute::IS_REPEATABLE | Attribute::TARGET_CLASS)]
+class AddColumn extends ColumnMigrationAttribute {
+	/**
+	 * @return string
+	 * @since 30.0.0
+	 */
+	public function definition(): string {
+		return empty($this->getName()) ?
+			'Addition of a new column to table \'' . $this->getTable() . '\''
+			: 'Addition of column \'' . $this->getName() . '\' to table \'' . $this->getTable() . '\'';
+	}
+}
diff --git a/lib/public/Migration/Attributes/AddIndex.php b/lib/public/Migration/Attributes/AddIndex.php
new file mode 100644
index 00000000000..a7da4173b29
--- /dev/null
+++ b/lib/public/Migration/Attributes/AddIndex.php
@@ -0,0 +1,27 @@
+<?php
+
+declare(strict_types=1);
+
+/**
+ * SPDX-FileCopyrightText: 2024 Nextcloud GmbH and Nextcloud contributors
+ * SPDX-License-Identifier: AGPL-3.0-or-later
+ */
+namespace OCP\Migration\Attributes;
+
+use Attribute;
+
+/**
+ * attribute on index creation
+ *
+ * @since 30.0.0
+ */
+#[Attribute(Attribute::IS_REPEATABLE | Attribute::TARGET_CLASS)]
+class AddIndex extends IndexMigrationAttribute {
+	/**
+	 * @return string
+	 * @since 30.0.0
+	 */
+	public function definition(): string {
+		return 'Addition of a new index to table \'' . $this->getTable() . '\'';
+	}
+}
diff --git a/lib/public/Migration/Attributes/ColumnMigrationAttribute.php b/lib/public/Migration/Attributes/ColumnMigrationAttribute.php
new file mode 100644
index 00000000000..8784f5bf2cf
--- /dev/null
+++ b/lib/public/Migration/Attributes/ColumnMigrationAttribute.php
@@ -0,0 +1,78 @@
+<?php
+
+declare(strict_types=1);
+
+/**
+ * SPDX-FileCopyrightText: 2024 Nextcloud GmbH and Nextcloud contributors
+ * SPDX-License-Identifier: AGPL-3.0-or-later
+ */
+namespace OCP\Migration\Attributes;
+
+use JsonSerializable;
+
+/**
+ * generic class related to migration attribute about column changes
+ *
+ * @since 30.0.0
+ */
+class ColumnMigrationAttribute extends MigrationAttribute implements JsonSerializable {
+	/**
+	 * @param string $table name of the database table
+	 * @param string $name name of the column
+	 * @param string $description description of the migration
+	 * @param array $notes notes about the migration/column
+	 * @since 30.0.0
+	 */
+	public function __construct(
+		string $table,
+		private string $name = '',
+		string $description = '',
+		array $notes = [],
+	) {
+		parent::__construct($table, $description, $notes);
+	}
+
+	/**
+	 * @param string $name
+	 *
+	 * @return $this
+	 * @since 30.0.0
+	 */
+	public function setName(string $name): self {
+		$this->name = $name;
+		return $this;
+	}
+
+	/**
+	 * @return string
+	 * @since 30.0.0
+	 */
+	public function getName(): string {
+		return $this->name;
+	}
+
+	/**
+	 * @param array $data
+	 *
+	 * @return $this
+	 * @since 30.0.0
+	 */
+	public function import(array $data): self {
+		parent::import($data);
+		$this->setName($data['name'] ?? '');
+		return $this;
+	}
+
+	/**
+	 * @return array
+	 * @since 30.0.0
+	 */
+	public function jsonSerialize(): array {
+		return array_merge(
+			parent::jsonSerialize(),
+			[
+				'name' => $this->getName(),
+			]
+		);
+	}
+}
diff --git a/lib/public/Migration/Attributes/CreateTable.php b/lib/public/Migration/Attributes/CreateTable.php
new file mode 100644
index 00000000000..df0418fa4bc
--- /dev/null
+++ b/lib/public/Migration/Attributes/CreateTable.php
@@ -0,0 +1,29 @@
+<?php
+
+declare(strict_types=1);
+
+/**
+ * SPDX-FileCopyrightText: 2024 Nextcloud GmbH and Nextcloud contributors
+ * SPDX-License-Identifier: AGPL-3.0-or-later
+ */
+namespace OCP\Migration\Attributes;
+
+use Attribute;
+
+/**
+ * attribute on table creation
+ *
+ * @since 30.0.0
+ */
+#[Attribute(Attribute::IS_REPEATABLE | Attribute::TARGET_CLASS)]
+class CreateTable extends TableMigrationAttribute {
+	/**
+	 * @return string
+	 * @since 30.0.0
+	 */
+	public function definition(): string {
+		$definition = 'Creation of new table \'' . $this->getTable() . '\'';
+		$definition .= empty($this->getColumns()) ? '' : ' with columns ' . implode(', ', $this->getColumns());
+		return $definition;
+	}
+}
diff --git a/lib/public/Migration/Attributes/DropColumn.php b/lib/public/Migration/Attributes/DropColumn.php
new file mode 100644
index 00000000000..1de0ba58489
--- /dev/null
+++ b/lib/public/Migration/Attributes/DropColumn.php
@@ -0,0 +1,29 @@
+<?php
+
+declare(strict_types=1);
+
+/**
+ * SPDX-FileCopyrightText: 2024 Nextcloud GmbH and Nextcloud contributors
+ * SPDX-License-Identifier: AGPL-3.0-or-later
+ */
+namespace OCP\Migration\Attributes;
+
+use Attribute;
+
+/**
+ * attribute on column drop
+ *
+ * @since 30.0.0
+ */
+#[Attribute(Attribute::IS_REPEATABLE | Attribute::TARGET_CLASS)]
+class DropColumn extends ColumnMigrationAttribute {
+	/**
+	 * @return string
+	 * @since 30.0.0
+	 */
+	public function definition(): string {
+		return empty($this->getName()) ?
+			'Deletion of a column from table \'' . $this->getTable() . '\''
+			: 'Deletion of column \'' . $this->getName() . '\' from table \'' . $this->getTable() . '\'';
+	}
+}
diff --git a/lib/public/Migration/Attributes/DropIndex.php b/lib/public/Migration/Attributes/DropIndex.php
new file mode 100644
index 00000000000..2702cbed9a7
--- /dev/null
+++ b/lib/public/Migration/Attributes/DropIndex.php
@@ -0,0 +1,27 @@
+<?php
+
+declare(strict_types=1);
+
+/**
+ * SPDX-FileCopyrightText: 2024 Nextcloud GmbH and Nextcloud contributors
+ * SPDX-License-Identifier: AGPL-3.0-or-later
+ */
+namespace OCP\Migration\Attributes;
+
+use Attribute;
+
+/**
+ * attribute on index drop
+ *
+ * @since 30.0.0
+ */
+#[Attribute(Attribute::IS_REPEATABLE | Attribute::TARGET_CLASS)]
+class DropIndex extends IndexMigrationAttribute {
+	/**
+	 * @return string
+	 * @since 30.0.0
+	 */
+	public function definition(): string {
+		return 'Deletion of an index from table \'' . $this->getTable() . '\'';
+	}
+}
diff --git a/lib/public/Migration/Attributes/DropTable.php b/lib/public/Migration/Attributes/DropTable.php
new file mode 100644
index 00000000000..e90e4804a3c
--- /dev/null
+++ b/lib/public/Migration/Attributes/DropTable.php
@@ -0,0 +1,27 @@
+<?php
+
+declare(strict_types=1);
+
+/**
+ * SPDX-FileCopyrightText: 2024 Nextcloud GmbH and Nextcloud contributors
+ * SPDX-License-Identifier: AGPL-3.0-or-later
+ */
+namespace OCP\Migration\Attributes;
+
+use Attribute;
+
+/**
+ * attribute on table drop
+ *
+ * @since 30.0.0
+ */
+#[Attribute(Attribute::IS_REPEATABLE | Attribute::TARGET_CLASS)]
+class DropTable extends TableMigrationAttribute {
+	/**
+	 * @return string
+	 * @since 30.0.0
+	 */
+	public function definition(): string {
+		return 'Deletion of table \'' . $this->getTable() . '\'';
+	}
+}
diff --git a/lib/public/Migration/Attributes/GenericMigrationAttribute.php b/lib/public/Migration/Attributes/GenericMigrationAttribute.php
new file mode 100644
index 00000000000..62d3bbf84d1
--- /dev/null
+++ b/lib/public/Migration/Attributes/GenericMigrationAttribute.php
@@ -0,0 +1,49 @@
+<?php
+
+declare(strict_types=1);
+
+/**
+ * SPDX-FileCopyrightText: 2024 Nextcloud GmbH and Nextcloud contributors
+ * SPDX-License-Identifier: AGPL-3.0-or-later
+ */
+namespace OCP\Migration\Attributes;
+
+use JsonSerializable;
+
+/**
+ * generic entry, used to replace migration attribute not yet known in current version
+ * but used in a future release
+ *
+ * @since 30.0.0
+ */
+class GenericMigrationAttribute extends MigrationAttribute implements JsonSerializable {
+	/**
+	 * @param array $details
+	 * @since 30.0.0
+	 */
+	public function __construct(
+		private array $details = []
+	) {
+		parent::__construct(
+			$details['table'] ?? '',
+			$details['description'] ?? '',
+			$details['notes'] ?? []
+		);
+	}
+
+	/**
+	 * @return string
+	 * @since 30.0.0
+	 */
+	public function definition(): string {
+		return json_encode($this->jsonSerialize(), JSON_UNESCAPED_SLASHES);
+	}
+
+	/**
+	 * @return array
+	 * @since 30.0.0
+	 */
+	public function jsonSerialize(): array {
+		return $this->details;
+	}
+}
diff --git a/lib/public/Migration/Attributes/IndexMigrationAttribute.php b/lib/public/Migration/Attributes/IndexMigrationAttribute.php
new file mode 100644
index 00000000000..14f800466ea
--- /dev/null
+++ b/lib/public/Migration/Attributes/IndexMigrationAttribute.php
@@ -0,0 +1,32 @@
+<?php
+
+declare(strict_types=1);
+
+/**
+ * SPDX-FileCopyrightText: 2024 Nextcloud GmbH and Nextcloud contributors
+ * SPDX-License-Identifier: AGPL-3.0-or-later
+ */
+namespace OCP\Migration\Attributes;
+
+use JsonSerializable;
+
+/**
+ * generic class related to migration attribute about index changes
+ *
+ * @since 30.0.0
+ */
+class IndexMigrationAttribute extends MigrationAttribute implements JsonSerializable {
+	/**
+	 * @param string $table name of the database table
+	 * @param string $description description of the migration
+	 * @param array $notes notes abour the migration/index
+	 * @since 30.0.0
+	 */
+	public function __construct(
+		string $table,
+		string $description = '',
+		array $notes = [],
+	) {
+		parent::__construct($table, $description, $notes);
+	}
+}
diff --git a/lib/public/Migration/Attributes/MigrationAttribute.php b/lib/public/Migration/Attributes/MigrationAttribute.php
new file mode 100644
index 00000000000..5b4550c4db5
--- /dev/null
+++ b/lib/public/Migration/Attributes/MigrationAttribute.php
@@ -0,0 +1,118 @@
+<?php
+
+declare(strict_types=1);
+
+/**
+ * SPDX-FileCopyrightText: 2024 Nextcloud GmbH and Nextcloud contributors
+ * SPDX-License-Identifier: AGPL-3.0-or-later
+ */
+namespace OCP\Migration\Attributes;
+
+use JsonSerializable;
+
+/**
+ * @since 30.0.0
+ */
+class MigrationAttribute implements JsonSerializable {
+	/**
+	 * @param string $table name of the database table
+	 * @param string $description description of the migration
+	 * @param array $notes notes about the migration
+	 * @since 30.0.0
+	 */
+	public function __construct(
+		private string $table,
+		private string $description = '',
+		private array $notes = [],
+	) {
+	}
+
+	/**
+	 * @param string $table
+	 *
+	 * @return $this
+	 * @since 30.0.0
+	 */
+	public function setTable(string $table): self {
+		$this->table = $table;
+		return $this;
+	}
+
+	/**
+	 * @return string
+	 * @since 30.0.0
+	 */
+	public function getTable(): string {
+		return $this->table;
+	}
+
+	/**
+	 * @param string $description
+	 *
+	 * @return $this
+	 * @since 30.0.0
+	 */
+	public function setDescription(string $description): self {
+		$this->description = $description;
+		return $this;
+	}
+
+	/**
+	 * @return string
+	 * @since 30.0.0
+	 */
+	public function getDescription(): string {
+		return $this->description;
+	}
+
+	/**
+	 * @param array $notes
+	 *
+	 * @return $this
+	 * @since 30.0.0
+	 */
+	public function setNotes(array $notes): self {
+		$this->notes = $notes;
+		return $this;
+	}
+
+	/**
+	 * @return array
+	 * @since 30.0.0
+	 */
+	public function getNotes(): array {
+		return $this->notes;
+	}
+
+	/**
+	 * @return string
+	 * @since 30.0.0
+	 */
+	public function definition(): string {
+		return json_encode($this->jsonSerialize(), JSON_UNESCAPED_SLASHES);
+	}
+
+	/**
+	 * @param array $data
+	 *
+	 * @return self
+	 * @since 30.0.0
+	 */
+	public function import(array $data): self {
+		return $this->setDescription($data['description'] ?? '')
+					->setNotes($data['notes'] ?? []);
+	}
+
+	/**
+	 * @return array
+	 * @since 30.0.0
+	 */
+	public function jsonSerialize(): array {
+		return [
+			'class' => get_class($this),
+			'table' => $this->getTable(),
+			'description' => $this->getDescription(),
+			'notes' => $this->getNotes()
+		];
+	}
+}
diff --git a/lib/public/Migration/Attributes/ModifyColumn.php b/lib/public/Migration/Attributes/ModifyColumn.php
new file mode 100644
index 00000000000..d90d0db4ec4
--- /dev/null
+++ b/lib/public/Migration/Attributes/ModifyColumn.php
@@ -0,0 +1,29 @@
+<?php
+
+declare(strict_types=1);
+
+/**
+ * SPDX-FileCopyrightText: 2024 Nextcloud GmbH and Nextcloud contributors
+ * SPDX-License-Identifier: AGPL-3.0-or-later
+ */
+namespace OCP\Migration\Attributes;
+
+use Attribute;
+
+/**
+ * attribute on column modification
+ *
+ * @since 30.0.0
+ */
+#[Attribute(Attribute::IS_REPEATABLE | Attribute::TARGET_CLASS)]
+class ModifyColumn extends ColumnMigrationAttribute {
+	/**
+	 * @return string
+	 * @since 30.0.0
+	 */
+	public function definition(): string {
+		return empty($this->getName()) ?
+			'Modification of a column from table \'' . $this->getTable() . '\''
+			: 'Modification of column \'' . $this->getName() . '\' from table \'' . $this->getTable() . '\'';
+	}
+}
diff --git a/lib/public/Migration/Attributes/TableMigrationAttribute.php b/lib/public/Migration/Attributes/TableMigrationAttribute.php
new file mode 100644
index 00000000000..0776e50387e
--- /dev/null
+++ b/lib/public/Migration/Attributes/TableMigrationAttribute.php
@@ -0,0 +1,78 @@
+<?php
+
+declare(strict_types=1);
+
+/**
+ * SPDX-FileCopyrightText: 2024 Nextcloud GmbH and Nextcloud contributors
+ * SPDX-License-Identifier: AGPL-3.0-or-later
+ */
+namespace OCP\Migration\Attributes;
+
+use JsonSerializable;
+
+/**
+ * generic class related to migration attribute about table changes
+ *
+ * @since 30.0.0
+ */
+class TableMigrationAttribute extends MigrationAttribute implements JsonSerializable {
+	/**
+	 * @param string $table name of the database table
+	 * @param array $columns list of columns
+	 * @param string $description description of the migration
+	 * @param array $notes notes about the migration/table
+	 * @since 30.0.0
+	 */
+	public function __construct(
+		string $table,
+		private array $columns = [],
+		string $description = '',
+		array $notes = [],
+	) {
+		parent::__construct($table, $description, $notes);
+	}
+
+	/**
+	 * @param array $columns
+	 *
+	 * @return $this
+	 * @since 30.0.0
+	 */
+	public function setColumns(array $columns): self {
+		$this->columns = $columns;
+		return $this;
+	}
+
+	/**
+	 * @return array
+	 * @since 30.0.0
+	 */
+	public function getColumns(): array {
+		return $this->columns;
+	}
+
+	/**
+	 * @param array $data
+	 *
+	 * @return $this
+	 * @since 30.0.0
+	 */
+	public function import(array $data): self {
+		parent::import($data);
+		$this->setColumns($data['columns'] ?? []);
+		return $this;
+	}
+
+	/**
+	 * @return array
+	 * @since 30.0.0
+	 */
+	public function jsonSerialize(): array {
+		return array_merge(
+			parent::jsonSerialize(),
+			[
+				'columns' => $this->getColumns(),
+			]
+		);
+	}
+}
diff --git a/tests/lib/Updater/ReleaseMetadataTest.php b/tests/lib/Updater/ReleaseMetadataTest.php
new file mode 100644
index 00000000000..25fe3949152
--- /dev/null
+++ b/tests/lib/Updater/ReleaseMetadataTest.php
@@ -0,0 +1,209 @@
+<?php
+
+/**
+ * SPDX-FileCopyrightText: 2024 Nextcloud GmbH and Nextcloud contributors
+ * SPDX-License-Identifier: AGPL-3.0-only
+ */
+namespace Test\Updater;
+
+use OC\Updater\ReleaseMetadata;
+use OCP\Http\Client\IClient;
+use OCP\Http\Client\IClientService;
+use OCP\Http\Client\IResponse;
+use PHPUnit\Framework\MockObject\MockObject;
+
+class ReleaseMetadataTest extends \Test\TestCase {
+	private IClientService| MockObject $clientService;
+
+	protected function setUp(): void {
+		parent::setUp();
+		$this->clientService = $this->getMockBuilder(IClientService::class)
+									->disableOriginalConstructor()
+									->getMock();
+	}
+
+	public function testDownloadMetadata() {
+		$client = $this->createMock(IClient::class);
+		$response = $this->createMock(IResponse::class);
+		$this->clientService->expects($this->once())
+							->method('newClient')
+							->with()
+							->willReturn($client);
+		$client->expects($this->once())
+			   ->method('get')
+			   ->willReturn($response);
+		$response->expects($this->once())
+				 ->method('getBody')
+				 ->with()
+				 ->willReturn($this->resultRequest());
+
+
+		$releaseMetadata = new ReleaseMetadata($this->clientService);
+		$this->assertSame($this->resultRequestArray(), $releaseMetadata->downloadMetadata('ouila'));
+	}
+
+	/**
+	 * @dataProvider getMetadataUrlProvider
+	 *
+	 * @param string $version
+	 * @param string $url
+	 */
+	public function testGetMetadata(string $version, string $url) {
+		$client = $this->createMock(IClient::class);
+		$response = $this->createMock(IResponse::class);
+		$this->clientService->expects($this->once())
+							->method('newClient')
+							->with()
+							->willReturn($client);
+		$client->expects($this->once())
+			   ->method('get')
+			   ->with($url)
+			   ->willReturn($response);
+
+		$response->expects($this->once())
+				 ->method('getBody')
+				 ->with()
+				 ->willReturn('{}');
+
+		$releaseMetadata = new ReleaseMetadata($this->clientService);
+		$releaseMetadata->getMetadata($version);
+	}
+
+	/**
+	 * @return array
+	 */
+	public function getMetadataUrlProvider(): array {
+		return [
+			[
+				'30.0.0',
+				'https://download.nextcloud.com/server/releases/nextcloud-30.0.0.metadata'
+			],
+			[
+				'30.0.0-beta1',
+				'https://download.nextcloud.com/server/prereleases/nextcloud-30.0.0-beta1.metadata'
+			],
+			[
+				'30',
+				'https://download.nextcloud.com/server/releases/latest-30.metadata'
+			]
+		];
+	}
+
+	private function resultRequest(): string {
+		return json_encode($this->resultRequestArray());
+	}
+
+	private function resultRequestArray(): array {
+		return [
+			'migrations' => [
+				'core' => [],
+				'apps' => [
+					'testing' => [
+						'30000Date20240102030405' => [
+							'class' => 'OCP\\Migration\\Attributes\\DropTable',
+							'table' => 'old_table',
+							'description' => '',
+							'notes' => [],
+							'columns' => []
+						],
+						[
+							'class' => 'OCP\\Migration\\Attributes\\CreateTable',
+							'table' => 'new_table',
+							'description' => 'Table is used to store things, but also to get more things',
+							'notes' => [
+								'this is a notice',
+								'and another one, if really needed'
+							],
+							'columns' => []
+						],
+						[
+							'class' => 'OCP\\Migration\\Attributes\\AddColumn',
+							'table' => 'my_table',
+							'description' => '',
+							'notes' => [],
+							'name' => '',
+							'type' => ''
+						],
+						[
+							'class' => 'OCP\\Migration\\Attributes\\AddColumn',
+							'table' => 'my_table',
+							'description' => '',
+							'notes' => [],
+							'name' => 'another_field',
+							'type' => ''
+						],
+						[
+							'class' => 'OCP\\Migration\\Attributes\\AddColumn',
+							'table' => 'other_table',
+							'description' => '',
+							'notes' => [],
+							'name' => 'last_one',
+							'type' => 'date'
+						],
+						[
+							'class' => 'OCP\\Migration\\Attributes\\AddIndex',
+							'table' => 'my_table',
+							'description' => '',
+							'notes' => [],
+							'type' => ''
+						],
+						[
+							'class' => 'OCP\\Migration\\Attributes\\AddIndex',
+							'table' => 'my_table',
+							'description' => '',
+							'notes' => [],
+							'type' => 'primary'
+						],
+						[
+							'class' => 'OCP\\Migration\\Attributes\\DropColumn',
+							'table' => 'other_table',
+							'description' => '',
+							'notes' => [],
+							'name' => '',
+							'type' => ''
+						],
+						[
+							'class' => 'OCP\\Migration\\Attributes\\DropColumn',
+							'table' => 'other_table',
+							'description' => 'field is not used anymore and replaced by \'last_one\'',
+							'notes' => [],
+							'name' => 'old_column',
+							'type' => ''
+						],
+						[
+							'class' => 'OCP\\Migration\\Attributes\\DropIndex',
+							'table' => 'other_table',
+							'description' => '',
+							'notes' => [],
+							'type' => ''
+						],
+						[
+							'class' => 'OCP\\Migration\\Attributes\\ModifyColumn',
+							'table' => 'other_table',
+							'description' => '',
+							'notes' => [],
+							'name' => '',
+							'type' => ''
+						],
+						[
+							'class' => 'OCP\\Migration\\Attributes\\ModifyColumn',
+							'table' => 'other_table',
+							'description' => '',
+							'notes' => [],
+							'name' => 'this_field',
+							'type' => ''
+						],
+						[
+							'class' => 'OCP\\Migration\\Attributes\\ModifyColumn',
+							'table' => 'other_table',
+							'description' => '',
+							'notes' => [],
+							'name' => 'this_field',
+							'type' => 'bigint'
+						]
+					]
+				]
+			]
+		];
+	}
+}