.NET 9.0 locking fixes

Directory.Packages.props

@@ -74,6 +74,7 @@
   <!-- Dependencies -->
   <ItemGroup>
     <PackageVersion Include="AspNet.Security.OAuth.GitHub" Version="8.1.0" />
+    <PackageVersion Include="Backport.System.Threading.Lock" Version="2.0.5" />
     <PackageVersion Include="Blazorise" Version="$(BlazoriseVersion)" />
     <PackageVersion Include="Blazorise.Bootstrap5" Version="$(BlazoriseVersion)" />
     <PackageVersion Include="Blazorise.DataGrid" Version="$(BlazoriseVersion)" />

samples/MeshRpc/Services/CounterStorage.cs

@@ -2,7 +2,7 @@ namespace Samples.MeshRpc.Services;
 
 public static class CounterStorage
 {
-    private static readonly object Lock = new();
+    private static readonly Lock Lock = new();
     private static readonly Dictionary<int, MutableState<Counter>> States = new();
 
     public static Counter Get(int key)

samples/MiniRpc/Program.cs

@@ -1,4 +1,4 @@
-using System.Runtime.Serialization;
+using System.Runtime.Serialization;
 using ActualLab.Fusion.Server;
 using ActualLab.IO;
 using ActualLab.Rpc;
@@ -103,7 +103,7 @@ public sealed partial record Chat_Post(
 
 public class Chat : IChat
 {
-    private readonly object _lock = new();
+    private readonly Lock _lock = new();
     private List<string> _posts = new();
 
     public virtual Task<List<string>> GetRecentMessages(CancellationToken cancellationToken = default)

samples/MultiServerRpc/Service.cs

@@ -26,7 +26,7 @@ public sealed partial record Chat_Post(
 
 public class Chat(ServerId serverId) : IChat
 {
-    private readonly object _lock = new();
+    private readonly Lock _lock = new();
     private readonly Dictionary<Symbol, List<string>> _chats = new();
 
     private ServerId ServerId { get; } = serverId;

src/ActualLab.CommandR/Operations/Operation.cs

@@ -6,11 +6,7 @@ namespace ActualLab.CommandR.Operations;
 
 public class Operation : IHasUuid, IHasId<Symbol>
 {
-#if NET9_0_OR_GREATER
     private readonly Lock _lock = new();
-#else
-    private readonly object _lock = new();
-#endif
     Symbol IHasId<Symbol>.Id => Uuid;
 
     public long? Index { get; set; }

src/ActualLab.Core/ActualLab.Core.csproj

@@ -22,6 +22,10 @@
     <PackageReference Include="Ulid" />
     <PackageReference Include="ZString" />
   </ItemGroup>
+
+  <ItemGroup Condition="!$([MSBuild]::IsTargetFrameworkCompatible('$(TargetFramework)', 'net9.0'))">
+    <PackageReference Include="Backport.System.Threading.Lock" />
+  </ItemGroup>	
 
   <ItemGroup Condition="!$(TargetFramework.StartsWith('netstandard2.0'))">
     <PackageReference Include="MemoryPack.Core" />

src/ActualLab.Core/Async/ProcessorBase.cs

@@ -4,11 +4,7 @@ public abstract class ProcessorBase : IAsyncDisposable, IDisposable, IHasWhenDis
 {
     private volatile Task? _disposeTask;
 
-#if NET9_0_OR_GREATER
-    protected Lock Lock { get; } = new();
-#else
-    protected object Lock { get; } = new();
-#endif
+    protected Lock Lock = new();
     protected CancellationTokenSource StopTokenSource { get; }
 
     public CancellationToken StopToken { get; }

src/ActualLab.Core/Collections/MutableDictionary.cs

@@ -24,11 +24,7 @@ public class MutableDictionary<TKey, TValue>(ImmutableDictionary<TKey, TValue> i
     : IMutableDictionary<TKey, TValue>
     where TKey : notnull
 {
-#if NET9_0_OR_GREATER
     private readonly Lock _lock = new();
-#else
-    private readonly object _lock = new();
-#endif
     private volatile ImmutableDictionary<TKey, TValue> _items = items;
 
     public ImmutableDictionary<TKey, TValue> Items {

src/ActualLab.Core/Collections/MutableList.cs

@@ -21,11 +21,7 @@ public interface IMutableList<T> : IReadOnlyMutableList<T>, IList<T>
 
 public class MutableList<T>(ImmutableList<T> items) : IMutableList<T>
 {
-#if NET9_0_OR_GREATER
     private readonly Lock _lock = new();
-#else
-    private readonly object _lock = new();
-#endif
     private volatile ImmutableList<T> _items = items;
 
     public ImmutableList<T> Items {

src/ActualLab.Core/Collections/MutablePropertyBag.cs

@@ -31,11 +31,7 @@ public interface IMutablePropertyBag : IReadOnlyPropertyBag
 [Newtonsoft.Json.JsonObject(Newtonsoft.Json.MemberSerialization.OptOut)]
 public sealed partial class MutablePropertyBag : IMutablePropertyBag
 {
-#if NET9_0_OR_GREATER
     private readonly Lock _lock = new();
-#else
-    private readonly object _lock = new();
-#endif
     private PropertyBag _snapshot;
 
     public event Action? Changed;

src/ActualLab.Core/Diagnostics/Samplers.cs

@@ -86,11 +86,7 @@ public static Sampler Random(double probability)
         if (probability >= 1)
             return Always;
 
-#if NET9_0_OR_GREATER
         Lock @lock = new();
-#else
-        object @lock = new();
-#endif
         var rnd = new Random();
         var maxIntBasedLimit = (int)((1d + int.MaxValue) * probability - 1);
         var sampler = new Sampler(nameof(Random), probability, () => {
@@ -127,11 +123,7 @@ public static Sampler AlternativeRandom(double probability)
         if (probability >= 1)
             return Always;
 
-#if NET9_0_OR_GREATER
         Lock @lock = new();
-#else
-        object @lock = new();
-#endif
         var rnd = new Random();
         var stepSize = 1d / probability;
         var maxIntBasedLimit = (int)((1d + int.MaxValue) * probability - 1);

src/ActualLab.Core/Generators/RandomStringGenerator.cs

@@ -14,7 +14,7 @@ public class RandomStringGenerator : Generator<string>, IDisposable
 
     protected readonly RandomNumberGenerator Rng;
     // ReSharper disable once InconsistentlySynchronizedField
-    protected object Lock => Rng;
+    protected Lock Lock = new();
 
     public string Alphabet { get; }
     public int Length { get; }

src/ActualLab.Core/IO/ConsoleExt.cs

@@ -4,11 +4,7 @@ namespace ActualLab.IO;
 
 public static class ConsoleExt
 {
-#if NET9_0_OR_GREATER
     private static readonly Lock Lock = new();
-#else
-    private static readonly object Lock = new();
-#endif
     private static TaskScheduler? _scheduler;
 
     public static TaskScheduler Scheduler {

src/ActualLab.Core/LazySlim.cs

@@ -32,14 +32,15 @@ public static LazySlim<TArg0, TArg1, TValue> New<TArg0, TArg1, TValue>(
 
 public sealed class LazySlim<TValue> : ILazySlim<TValue>
 {
+    private readonly Lock _syncLock = new();
     private Func<TValue>? _factory;
     private TValue _value;
 
     public TValue Value {
         get {
             // Double-check locking
             if (_factory == null) return _value;
-            lock (this) {
+            lock (_syncLock) {
                 if (_factory == null) return _value;
                 _value = _factory.Invoke();
                 _factory = null;

src/ActualLab.Core/Mathematics/PrimeSieve.cs

@@ -2,11 +2,7 @@ namespace ActualLab.Mathematics;
 
 public class PrimeSieve
 {
-#if NET9_0_OR_GREATER
     private static readonly Lock Lock = new();
-#else
-    private static readonly object Lock = new();
-#endif
     private static PrimeSieve? _instance;
 
     private readonly int _limitSqrt;

src/ActualLab.Core/Net/RetryDelayer.cs

@@ -5,11 +5,7 @@ public class RetryDelayer : IRetryDelayer
     private CancellationTokenSource _cancelDelaysCts = new();
 
     private MomentClock? _clock;
-#if NET9_0_OR_GREATER
     protected readonly Lock Lock = new();
-#else
-    protected readonly object Lock = new();
-#endif
 
     public Func<MomentClock> ClockProvider { get; init; } = static () => CpuClock.Instance;
     public MomentClock Clock => _clock ??= ClockProvider.Invoke();

src/ActualLab.Core/OS/HardwareInfo.cs

@@ -3,11 +3,7 @@ namespace ActualLab.OS;
 public static class HardwareInfo
 {
     private const int RefreshIntervalTicks = 30_000; // Tick = millisecond
-#if NET9_0_OR_GREATER
     private static readonly Lock Lock = new();
-#else
-    private static readonly object Lock = new();
-#endif
     private static volatile int _processorCount;
     private static volatile int _processorCountPo2;
     private static volatile int _lastRefreshTicks =

src/ActualLab.Core/Requirement.cs

@@ -26,11 +26,7 @@ public abstract record Requirement<
 {
     private const string MustExistFieldOrPropertyName = "MustExist";
     // ReSharper disable once StaticMemberInGenericType
-#if NET9_0_OR_GREATER
     private static readonly Lock MustExistLock = new();
-#else
-    private static readonly object MustExistLock = new();
-#endif
     private static volatile Requirement<T>? _mustExist;
 
     public static Requirement<T> MustExist {

src/ActualLab.Core/StaticLog.cs

@@ -2,11 +2,7 @@ namespace ActualLab;
 
 public static class StaticLog
 {
-#if NET9_0_OR_GREATER
     private static readonly Lock Lock = new();
-#else
-    private static readonly object Lock = new();
-#endif
     private static readonly ConcurrentDictionary<object, ILogger> Cache = new();
     private static volatile ILoggerFactory _factory = NullLoggerFactory.Instance;
 

src/ActualLab.Core/Time/TickSource.cs

@@ -6,11 +6,7 @@ public sealed class TickSource(TimeSpan period)
     // On other OSes it will be ~= t = N*NativeTimerPeriod so that t >= 15ms.
     public static TickSource Default { get; set; } = new(TimeSpan.FromMilliseconds(15));
 
-#if NET9_0_OR_GREATER
     private readonly Lock _lock = new();
-#else
-    private readonly object _lock = new();
-#endif
     private volatile Task _whenNextTick = Task.CompletedTask;
 
     public TimeSpan Period { get; } = period > TimeSpan.Zero

src/ActualLab.Core/Time/TimerSet.cs

@@ -14,11 +14,7 @@ public record TimerSetOptions
 public sealed class TimerSet<TTimer> : WorkerBase
     where TTimer : notnull
 {
-#if NET9_0_OR_GREATER
     private readonly Lock _lock = new();
-#else
-    private readonly object _lock = new();
-#endif
     private readonly Action<TTimer>? _fireHandler;
     private readonly RadixHeapSet<TTimer> _timers = new(45);
     private readonly Moment _start;

src/ActualLab.Core/Trimming/CodeKeeper.cs

@@ -5,11 +5,7 @@ namespace ActualLab.Trimming;
 
 public abstract class CodeKeeper
 {
-#if NET9_0_OR_GREATER
     private static readonly Lock Lock = new();
-#else
-    private static readonly object Lock = new();
-#endif
     private static readonly List<Action> Actions = new();
     private static readonly HashSet<Action> ActionSet = new();
 

src/ActualLab.Fusion.Blazor.Authentication/AuthStateProvider.cs

@@ -21,11 +21,7 @@ public Options()
         }
     };
 
-#if NET9_0_OR_GREATER
     private readonly Lock _lock = new();
-#else
-    private readonly object _lock = new();
-#endif
     private Session? _session;
     private volatile Task<AuthState> _authStateTask;
     private volatile Task<AuthenticationState> _authenticationStateTask;

src/ActualLab.Fusion.EntityFramework/Sharding/DbShardRegistry.cs

@@ -20,7 +20,7 @@ public interface IDbShardRegistry<TContext> : IDbShardRegistry;
 
 public class DbShardRegistry<TContext> : IDbShardRegistry<TContext>, IDisposable
 {
-    protected readonly object Lock = new();
+    protected readonly Lock Lock = new();
     private readonly MutableState<ImmutableHashSet<DbShard>> _shards;
     private readonly MutableState<ImmutableHashSet<DbShard>> _usedShards;
     private readonly ComputedState<ImmutableHashSet<DbShard>> _eventProcessorShards;

src/ActualLab.Fusion/Client/Caching/FlushingRemoteComputedCache.cs

@@ -12,11 +12,7 @@ public abstract class FlushingRemoteComputedCache : RemoteComputedCache
         public MomentClock? Clock { get; init; }
     }
 
-#if NET9_0_OR_GREATER
     protected readonly Lock Lock = new();
-#else
-    protected readonly object Lock = new();
-#endif
     protected readonly MomentClock Clock;
     protected Dictionary<RpcCacheKey, RpcCacheValue> FlushQueue = new();
     protected Dictionary<RpcCacheKey, RpcCacheValue> FlushingQueue = new();
@@ -95,19 +91,19 @@ protected async Task DelayedFlush(TimeSpan? flushDelay, CancellationToken cancel
             }
         }
 
-        Monitor.Enter(Lock);
+        Lock.Enter();
         try {
             while (true) {
                 var flushingTask = FlushingTask;
                 if (flushingTask.IsCompleted)
                     break;
 
-                Monitor.Exit(Lock);
+                Lock.Exit();
                 try {
                     await flushingTask.SilentAwait(false);
                 }
                 finally {
-                    Monitor.Enter(Lock);
+                    Lock.Enter();
                 }
             }
             var flushingQueue = FlushingQueue = FlushQueue;
@@ -116,7 +112,7 @@ protected async Task DelayedFlush(TimeSpan? flushDelay, CancellationToken cancel
             FlushTask = null;
         }
         finally {
-            Monitor.Exit(Lock);
+            Lock.Exit();
         }
     }
 }

src/ActualLab.Fusion/Client/Caching/RemoteComputedCache.Static.cs

@@ -6,11 +6,7 @@ namespace ActualLab.Fusion.Client.Caching;
 public partial class RemoteComputedCache
 {
     private static Func<ComputeMethodInput, RpcPeer, Task>? _updateDelayer;
-#if NET9_0_OR_GREATER
     private static readonly Lock Lock = new();
-#else
-    private static readonly object Lock = new();
-#endif
 
     public static Func<ComputeMethodInput, RpcPeer, Task>? UpdateDelayer {
         [MethodImpl(MethodImplOptions.AggressiveInlining)]

src/ActualLab.Fusion/Computed.cs

@@ -35,10 +35,7 @@ public abstract partial class Computed(ComputedOptions options, ComputedInput in
     // ReSharper disable once InconsistentNaming
     private InvalidatedHandlerSet _invalidated;
 
-    protected object Lock {
-        [MethodImpl(MethodImplOptions.AggressiveInlining)]
-        get => this;
-    }
+    protected Lock Lock = new();
 
     protected ComputedFlags Flags {
         [MethodImpl(MethodImplOptions.AggressiveInlining)]

src/ActualLab.Fusion/ComputedRegistry.cs

@@ -24,11 +24,7 @@ public sealed record Options
         public GCHandlePool? GCHandlePool { get; init; } = null;
     }
 
-#if NET9_0_OR_GREATER
     private readonly Lock _lock = new();
-#else
-    private readonly object _lock = new();
-#endif
     private readonly ConcurrentDictionary<ComputedInput, GCHandle> _storage;
     private readonly GCHandlePool _gcHandlePool;
     private StochasticCounter _opCounter;

src/ActualLab.Fusion/ComputedSource.cs

@@ -23,7 +23,7 @@ public class ComputedSource<T> : ComputedInput,
     private ILogger? _log;
 
     protected AsyncLock AsyncLock { get; }
-    protected object Lock => AsyncLock;
+    protected Lock Lock = new();
     protected ILogger Log => _log ??= Services.LogFor(GetType());
 
     public IServiceProvider Services { get; }

src/ActualLab.Fusion/Configuration/FusionDefaults.cs

@@ -4,11 +4,7 @@ namespace ActualLab.Fusion;
 
 public static class FusionDefaults
 {
-#if NET9_0_OR_GREATER
     private static readonly Lock Lock = new();
-#else
-    private static readonly object Lock = new();
-#endif
     private static FusionMode _mode;
 
     public static FusionMode Mode {