fix: Avoid race condition that may initialize a document twice on the…

… clients Signed-off-by: Julius Härtl <[email protected]>
nextcloud · Mar 13, 2024 · 9412ae1 · 9412ae1
1 parent f32d786
commit 9412ae1
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Showing 2 changed files with 9 additions and 2 deletions.
diff --git a/lib/Service/ApiService.php b/lib/Service/ApiService.php
@@ -37,6 +37,7 @@
 use OCP\AppFramework\Http;
 use OCP\AppFramework\Http\DataResponse;
 use OCP\Constants;
+use OCP\Files\AlreadyExistsException;
 use OCP\Files\InvalidPathException;
 use OCP\Files\Lock\ILock;
 use OCP\Files\NotFoundException;
@@ -117,7 +118,12 @@ public function create(?int $fileId = null, ?string $filePath = null, ?string $t
 
 			if ($freshSession) {
 				$this->logger->info('Create new document of ' . $file->getId());
-				$document = $this->documentService->createDocument($file);
+				try {
+					$document = $this->documentService->createDocument($file);
+				} catch (AlreadyExistsException) {
+					$freshSession = false;
+					$document = $this->documentService->getDocument($file->getId());
+				}
 			} else {
 				$this->logger->info('Keep previous document of ' . $file->getId());
 			}

diff --git a/lib/Service/DocumentService.php b/lib/Service/DocumentService.php
@@ -41,6 +41,7 @@
 use OCP\Constants;
 use OCP\DB\Exception;
 use OCP\DirectEditing\IManager;
+use OCP\Files\AlreadyExistsException;
 use OCP\Files\Config\IUserMountCache;
 use OCP\Files\File;
 use OCP\Files\Folder;
@@ -157,7 +158,7 @@ public function createDocument(File $file): Document {
 		} catch (Exception $e) {
 			if ($e->getReason() === Exception::REASON_UNIQUE_CONSTRAINT_VIOLATION) {
 				// Document might have been created in the meantime
-				return $this->documentMapper->find($file->getId());
+				throw new AlreadyExistsException();
 			}
 
 			throw $e;