1 files changed, 111 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..f5b850fff76
--- /dev/null
+++ b/core/Command/Db/Migrations/PreviewCommand.php
@@ -0,0 +1,111 @@
+<?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 readonly MetadataManager $metadataManager,
+		private readonly 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();
+
+		$unsupportedApps = $this->metadataManager->getUnsupportedApps($metadata['migrations']);
+		if (!empty($unsupportedApps)) {
+			$output->writeln('');
+			$output->writeln('Those apps are not supporting metadata yet and might initiate migrations on upgrade: <info>' . implode(', ', $unsupportedApps) . '</info>');
+		}
+
+		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) {
+			$attributesStr = [];
+			if (empty($attributes)) {
+				$attributesStr[] = '<comment>(metadata not set)</comment>';
+			}
+			foreach ($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)]);
+		}
+	}
+}