fix(preview): Better handle errors while migrating previews

Signed-off-by: Carl Schwan <carlschwan@kde.org>

core/BackgroundJobs/PreviewMigrationJob.php

@@ -19,6 +19,7 @@ use OCP\IAppConfig;
 use OCP\IConfig;
 use OCP\IDBConnection;
 use Override;
+use Psr\Log\LoggerInterface;
 
 class PreviewMigrationJob extends TimedJob {
 	private string $previewRootPath;
@@ -30,6 +31,7 @@ class PreviewMigrationJob extends TimedJob {
 		private readonly IDBConnection $connection,
 		private readonly IRootFolder $rootFolder,
 		private readonly PreviewMigrationService $migrationService,
+		private readonly LoggerInterface $logger,
 	) {
 		parent::__construct($time);
 
@@ -95,11 +97,23 @@ class PreviewMigrationJob extends TimedJob {
 		}
 
 		foreach ($fileIds as $fileId) {
-			$this->migrationService->migrateFileId($fileId, flatPath: false);
+			try {
+				$this->migrationService->migrateFileId($fileId, flatPath: false);
+			} catch (\Exception $e) {
+				$this->logger->error('Failed to migrate preview with fileId: ' . $fileId . ' (hierarchical file structure)', [
+					'exception' => $e,
+				]);
+			}
 		}
 
 		foreach ($flatFileIds as $fileId) {
-			$this->migrationService->migrateFileId($fileId, flatPath: true);
+			try {
+				$this->migrationService->migrateFileId($fileId, flatPath: true);
+			} catch (\Exception $e) {
+				$this->logger->error('Failed to migrate preview with fileId: ' . $fileId . ' (legacy file structure)', [
+					'exception' => $e,
+				]);
+			}
 		}
 		return $foundPreview;
 	}

lib/private/Preview/PreviewMigrationService.php

@@ -93,8 +93,9 @@ class PreviewMigrationService {
 			->where($qb->expr()->eq('fileid', $qb->createNamedParameter($fileId)))
 			->setMaxResults(1);
 
-		$result = $qb->executeQuery();
-		$result = $result->fetchAssociative();
+		$cursor = $qb->executeQuery();
+		$result = $cursor->fetchAssociative();
+		$cursor->closeCursor();
 
 		if ($result !== false) {
 			foreach ($previewFiles as $previewFile) {
@@ -108,7 +109,11 @@ class PreviewMigrationService {
 				$preview->generateId();
 				try {
 					$preview = $this->previewMapper->insert($preview);
-				} catch (Exception) {
+				} catch (Exception $e) {
+					if ($e->getReason() !== Exception::REASON_UNIQUE_CONSTRAINT_VIOLATION) {
+						throw $e;
+					}
+
 					$delete = $this->connection->getQueryBuilder();
 					// We already have this preview in the preview table, skip
 					$delete->delete('filecache')
@@ -180,7 +185,11 @@ class PreviewMigrationService {
 				break;
 			}
 
-			$folder = $this->appData->getFolder($current);
+			try {
+				$folder = $this->appData->getFolder($current);
+			} catch (NotFoundException) {
+				break;
+			}
 			if (count($folder->getDirectoryListing()) !== 0) {
 				break;
 			}

tests/lib/Preview/PreviewMigrationJobTest.php

@@ -131,7 +131,8 @@ class PreviewMigrationJobTest extends TestCase {
 				$this->previewMapper,
 				$this->storageFactory,
 				Server::get(IAppDataFactory::class),
-			)
+			),
+			$this->logger,
 		);
 		$this->invokePrivate($job, 'run', [[]]);
 		$this->assertEquals(0, count($this->previewAppData->getDirectoryListing()));
@@ -168,7 +169,8 @@ class PreviewMigrationJobTest extends TestCase {
 				$this->previewMapper,
 				$this->storageFactory,
 				Server::get(IAppDataFactory::class),
-			)
+			),
+			$this->logger,
 		);
 		$this->invokePrivate($job, 'run', [[]]);
 		$this->assertEquals(0, count($this->previewAppData->getDirectoryListing()));
@@ -213,7 +215,8 @@ class PreviewMigrationJobTest extends TestCase {
 				$this->previewMapper,
 				$this->storageFactory,
 				Server::get(IAppDataFactory::class),
-			)
+			),
+			$this->logger,
 		);
 		$this->invokePrivate($job, 'run', [[]]);
 		$previews = iterator_to_array($this->previewMapper->getAvailablePreviewsForFile(5));