From 531f5d1e4fcbc3e3f1801b272935affbed0acd90 Mon Sep 17 00:00:00 2001
From: Simon L <szaimen@e.mail.de>
Date: Fri, 3 Nov 2023 11:47:12 +0100
Subject: [PATCH 1/2] fix semaphore guarding

Signed-off-by: Simon L <szaimen@e.mail.de>
---
 lib/private/Preview/Generator.php | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/lib/private/Preview/Generator.php b/lib/private/Preview/Generator.php
index 4a1270fa4a60b..d936f1d65ad2a 100644
--- a/lib/private/Preview/Generator.php
+++ b/lib/private/Preview/Generator.php
@@ -244,7 +244,7 @@ public static function guardWithSemaphore(int $semId, int $concurrency) {
 	 * @return bool
 	 */
 	public static function unguardWithSemaphore($semId): bool {
-		if (!is_resource($semId) || !extension_loaded('sysvsem')) {
+		if ($semId === false || get_class($semId) !== 'SysvSemaphore' || !extension_loaded('sysvsem')) {
 			return false;
 		}
 		return sem_release($semId);

From b681cf735a29b6ae25e03813b2efe77e4fe25613 Mon Sep 17 00:00:00 2001
From: Simon L <szaimen@e.mail.de>
Date: Fri, 3 Nov 2023 15:27:17 +0100
Subject: [PATCH 2/2] address review

Signed-off-by: Simon L <szaimen@e.mail.de>
---
 build/psalm-baseline.xml          | 7 -------
 lib/private/Preview/Generator.php | 8 ++++----
 2 files changed, 4 insertions(+), 11 deletions(-)

diff --git a/build/psalm-baseline.xml b/build/psalm-baseline.xml
index 8a2c728ab5b4b..273c7ef470946 100644
--- a/build/psalm-baseline.xml
+++ b/build/psalm-baseline.xml
@@ -3075,14 +3075,7 @@
   <file src="lib/private/Preview/Generator.php">
     <InvalidArgument>
       <code>$maxPreviewImage</code>
-      <code>$semId</code>
     </InvalidArgument>
-    <InvalidReturnStatement>
-      <code>$sem</code>
-    </InvalidReturnStatement>
-    <InvalidReturnType>
-      <code>false|resource</code>
-    </InvalidReturnType>
     <LessSpecificReturnType>
       <code>null|string</code>
     </LessSpecificReturnType>
diff --git a/lib/private/Preview/Generator.php b/lib/private/Preview/Generator.php
index d936f1d65ad2a..958f58e2a0179 100644
--- a/lib/private/Preview/Generator.php
+++ b/lib/private/Preview/Generator.php
@@ -221,7 +221,7 @@ public function generatePreviews(File $file, array $specifications, $mimeType =
 	 *
 	 * @param int $semId
 	 * @param int $concurrency
-	 * @return false|resource the semaphore on success or false on failure
+	 * @return false|\SysvSemaphore the semaphore on success or false on failure
 	 */
 	public static function guardWithSemaphore(int $semId, int $concurrency) {
 		if (!extension_loaded('sysvsem')) {
@@ -240,11 +240,11 @@ public static function guardWithSemaphore(int $semId, int $concurrency) {
 	/**
 	 * Releases the semaphore acquired from {@see Generator::guardWithSemaphore()}.
 	 *
-	 * @param resource|bool $semId the semaphore identifier returned by guardWithSemaphore
+	 * @param false|\SysvSemaphore $semId the semaphore identifier returned by guardWithSemaphore
 	 * @return bool
 	 */
-	public static function unguardWithSemaphore($semId): bool {
-		if ($semId === false || get_class($semId) !== 'SysvSemaphore' || !extension_loaded('sysvsem')) {
+	public static function unguardWithSemaphore(false|\SysvSemaphore $semId): bool {
+		if ($semId === false || !($semId instanceof \SysvSemaphore)) {
 			return false;
 		}
 		return sem_release($semId);