From 9412ae1f2afb6db81c4465a81032e6697bf7cf73 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Julius=20H=C3=A4rtl?= <jus@bitgrid.net>
Date: Wed, 13 Mar 2024 09:25:40 +0100
Subject: [PATCH] fix: Avoid race condition that may initialize a document
 twice on the clients
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Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

Signed-off-by: Julius Härtl <jus@bitgrid.net>
---
 lib/Service/ApiService.php      | 8 +++++++-
 lib/Service/DocumentService.php | 3 ++-
 2 files changed, 9 insertions(+), 2 deletions(-)

diff --git a/lib/Service/ApiService.php b/lib/Service/ApiService.php
index 436ddc73eee..bcd89e4ded6 100644
--- 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
index 4784f1b32ae..5b1cb09d251 100644
--- 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;