From 6ccdaad0a47351d30cfde39c7470ae26bb6f7567 Mon Sep 17 00:00:00 2001
From: JPVenson <github@jpb.email>
Date: Sun, 7 Jun 2026 14:29:36 -0400
Subject: Backport pull request #16944 from jellyfin/release-10.11.z

Add lockhelper for UserManager

Original-merge: 39958ad9e51f83f520803aa9bc5e70e58f3a0836

Merged-by: Bond-009 <bond.009@outlook.com>

Backported-by: Bond_009 <bond.009@outlook.com>
---
 .../Users/UserManagerLockHelperTests.cs            | 89 ++++++++++++++++++++++
 1 file changed, 89 insertions(+)
 create mode 100644 tests/Jellyfin.Server.Implementations.Tests/Users/UserManagerLockHelperTests.cs

(limited to 'tests/Jellyfin.Server.Implementations.Tests/Users/UserManagerLockHelperTests.cs')

diff --git a/tests/Jellyfin.Server.Implementations.Tests/Users/UserManagerLockHelperTests.cs b/tests/Jellyfin.Server.Implementations.Tests/Users/UserManagerLockHelperTests.cs
new file mode 100644
index 0000000000..ab6f0fd32e
--- /dev/null
+++ b/tests/Jellyfin.Server.Implementations.Tests/Users/UserManagerLockHelperTests.cs
@@ -0,0 +1,89 @@
+using System;
+using System.Threading.Tasks;
+using Jellyfin.Server.Implementations.Users;
+using Xunit;
+
+namespace Jellyfin.Server.Implementations.Tests.Users
+{
+    public class UserManagerLockHelperTests
+    {
+        [Fact]
+        public async Task LockAsync_WhenNested_DoesNotAcquireSecondLockAndRestoresStateOnDispose()
+        {
+            UserManager.LockHelper.IsNestedLock.Value = 0;
+            using var helper = new UserManager.LockHelper();
+            var key = Guid.NewGuid();
+
+            Assert.True(helper.ShouldLock());
+
+            var outerHandle = await helper.LockAsync(key);
+            Assert.False(helper.ShouldLock());
+
+            var innerHandle = await helper.LockAsync(key);
+            Assert.False(helper.ShouldLock());
+
+            innerHandle.Dispose();
+            Assert.False(helper.ShouldLock());
+
+            outerHandle.Dispose();
+            Assert.True(helper.ShouldLock());
+        }
+
+        [Fact]
+        public async Task LockAsync_WithSameKey_BlocksSecondLockUntilFirstIsReleased()
+        {
+            UserManager.LockHelper.IsNestedLock.Value = 0;
+            using var helper = new UserManager.LockHelper();
+            var key = Guid.NewGuid();
+
+            var firstAcquired = new TaskCompletionSource<bool>(TaskCreationOptions.RunContinuationsAsynchronously);
+            var releaseFirst = new TaskCompletionSource<bool>(TaskCreationOptions.RunContinuationsAsynchronously);
+            var secondEntered = false;
+
+            var firstTask = Task.Run(async () =>
+            {
+                using var firstHandle = await helper.LockAsync(key);
+                firstAcquired.SetResult(true);
+                await releaseFirst.Task;
+            });
+
+            await firstAcquired.Task;
+
+            var secondTask = Task.Run(async () =>
+            {
+                using var secondHandle = await helper.LockAsync(key);
+                secondEntered = true;
+            });
+
+            await Task.Delay(100);
+            Assert.False(secondEntered);
+
+            releaseFirst.SetResult(true);
+
+            await Task.WhenAll(firstTask, secondTask);
+            Assert.True(secondEntered);
+        }
+
+        [Fact]
+        public async Task LockAsync_WhenDisposed_ThrowsObjectDisposedException()
+        {
+            UserManager.LockHelper.IsNestedLock.Value = 0;
+            using var helper = new UserManager.LockHelper();
+            helper.Dispose();
+
+            await Assert.ThrowsAsync<ObjectDisposedException>(async () => await helper.LockAsync(Guid.NewGuid()));
+        }
+
+        [Fact]
+        public void Dispose_WhenCalledMultipleTimes_DoesNotThrow()
+        {
+            UserManager.LockHelper.IsNestedLock.Value = 0;
+            using var helper = new UserManager.LockHelper();
+
+            helper.Dispose();
+            var ex = Record.Exception(() => helper.Dispose());
+
+            Assert.Null(ex);
+        }
+    }
+}
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