Changelog

All notable changes to ActualLab.Fusion are documented in this file.

The format is based on Keep a Changelog, and this project adheres to Semantic Versioning.

+HexNumber after version number is the commit hash of this version. It isn't included into the NuGet package version.

12.0.45+0ee956d2

Release date: 2026-01-29

Performance

• Simplified RpcOutboundMessage by replacing WhenSerialized Task with synchronous SendHandler callback; dependencies like RpcOutboundCall.SendXxx, RpcStream.OnItem, OnBatch, and OnEnd transitioned from Task to void return type reducing task allocations in the RPC send path, bringing ~20% performance improvement.

Tests

• Added comprehensive unit tests for TaskCompletionHandler covering various task states (completed, faulted, cancelled) and all handler variants (1, 2, 3 state objects)

Infrastructure

• Removed obsolete docs.sln file
• Removed JetBrains.Annotations package reference
• Updated package versions: Blazorise 1.8.9 (used only in samples), Bullseye 6.1.0, and CliWrap 3.10.0 (used in Build.csproj)
• Updated analyzer packages: Moq.Analyzers, xunit.analyzers, Roslynator.Analyzers, Meziantou.Analyzer.

12.0.34+842f172c

Release date: 2026-01-28

Added

• Native little-endian serialization support in RPC serializers with optimized memory handling
• TestServiceProviderTag to tag test ServiceProviders and allow services to detect whether they're running in test containers
• New MemoryReader and SpanWriter helpers in ActualLab.Core.IO.Internal

Performance

• Improved RPC performance dedicated path for little endian serialization and delegate caching
• Eliminated RpcPeer.Send indirection layer - RpcTransport.Send now handles error handling directly, reducing call stack depth and improving RPC throughput
• Introduced TaskCompletionHandler - a pooled helper for attaching completion callbacks to tasks. Each instance caches its delegate, and instances are pooled using thread-static pools to minimize allocations in hot paths like RPC transport error handling
• Enabled UseUnsafeAccessors build configuration for .NET 8+ targets, improving internal reflection-based operations performance

Fixed

• Big endian system support: serialization, RPC, and all dependent code now correctly use BinaryPrimitives.WriteInt32LittleEndian and similar methods to ensure consistent byte ordering across different CPU architectures

Tests

• Added ResetClientServices() calls to all relevant Fusion and RPC tests
• Refactored RPC test organization for better separation of concerns.

Documentation

• Added interactive BarChart component for performance benchmarks visualization
• Improved Mermaid flowchart styles and edge label rendering
• Updated Performance page with new benchmark visualizations
• Integrated CHANGELOG into the documentation website
• Updated coding style guide to clarify async method naming conventions

12.0.9+3e71b6ef

Release date: 2026-01-27

Breaking Changes

• New v6 serialization format: mempack6, msgpack6 and their variants with c suffix
• All serialization formats below v5 are gone, use v11.5.1 if you still need them
• WebSocketChannel is replaced by RpcWebSocketTransport
• All authentication-related types from ActualLab.Fusion.Server are moved to ActualLab.Fusion.Ext.* assemblies and changed namespace from ActualLab.Fusion.Server.Authentication to ActualLab.Fusion.Authentication, so referencing ActualLab.Fusion.Server assembly now doesn't "drag" the authentication-related types into your project (and that was the reason for this change).

Added

• mempack6 and msgpack6 serialization format versions; they offer a tiny improvement (2 bytes per call) over v5, and that's only because the zero-copy serialization in RPC transport layer made v5 a bit less efficient (it has to reserve 5 bytes for the message length, because it uses WriteVarUInt32 for length, so v6 changes length encoding to regular UInt32).
• RpcStream.BatchSize property for controlling stream batching behavior (default: 64, range: 1..1024)
• Real-time stock ticker demo added to TodoApp sample.

Changed

• Consolidated buffer size properties in RpcWebSocketTransport (renamed WriteFrameSize to FrameSize)
• Very significant changes in ActualLab.Rpc internals. In particular, old RpcMessage is now represented by RpcOutboundMessage and RpcInboundMessage types, all serialization-related methods now accept different arguments, etc.

Performance

• Zero-copy serialization in RPC transport layer. Earlier an intermediate buffer (ArgumentData) was used to serialize RPC call arguments and results. Later RpcMessage (envelope) serializer was combining that data with other required pieces (method reference, call ID, etc.) in the final buffer. Now the intermediate buffer is eliminated, which significantly boosts RPC performance on large messages. Stream10K test shows almost 3x speed improvement on 10KB items.
• Switched WriteChannelOptions to UnboundedChannelOptions
• Buffer renewal and reuse logic was significantly improved as well.

Documentation

• New documentation website: https://fusion.actuallab.net/

11.4.7+3045fd2c

Release date: 2025-01-05

Added

• Updated EntityFrameworkCore and Npgsql versions to 10.0. There is currently no MySql EF Core provider for EF10, so if you want to use Fusion with MySql, the latest version that targets EF9 is 11.4.3; you can also add binding redirects for EF9 manually in your project.
• RpcMethodAttribute for method-level RPC configuration
• v5 serialization formats with proper polymorphic null value support, including json5, njson5, msgpack5, msgpack5c, mempackc, and mempack5c.
• New IRpcMiddleware stack replacing IRpcInboundCallPreprocessor
• RpcLocalExecutionMode enum and new RpcLocalExecutionMode.Constrained, RpcLocalExecutionMode.ConstrainedEntry modes
• IOperationEventSource interface with Operation.AddEvent(...) overload for event sourcing
• IWorker.Run overload with CancellationToken.
• Much more robust RPC (re)routing logic in RpcInterceptor, RpcRoutingCommandHandler, and RemoteComputeMethodFunction.

Changed

• Moved all RpcXxx delegates to RpcXxxOptions members for clarity. E.g., RpcOutboundCallOptions.RouterFactory replaces RpcCallRouter delegate.
• Renamed RpcShardRoutingMode to RpcLocalExecutionMode
• Renamed RpcDefaultSessionInboundCallPreprocessor to RpcDefaultSessionReplacer
• Simplified RpcSerializationFormatResolver (the legacy resolver for the "unspecified" format is gone)
• Improved RpcServiceDef and RpcMethodDef constructors
• Improved ComputedOptions caching
• Updated .NET SDK to version 10.0.101.

Performance

• Multiple improvements in inbound call processing performance, such as handcrafted server invokers for most frequent RPC system calls like $sys.Ok
• WebSocketChannel.Options got ReadMode, which can be Buffered or Unbuffered. The new Unbuffered mode allows reading directly from WebSocket bypassing ChannelReader, it's used by default now.
• GetUnsafe in GenericInstanceCache to eliminate some unnecessary type casts
• Overall, v11.4.X is ~5-10% faster on RPC benchmarks.

Documentation

• Migrated Parts 01-13 from the old tutorial, though only parts 01-03 are truly edited at this point
• Added TOCs to videos on Fusion and ActualLab.Rpc
• Added GitHub workflow for deploying documentation to GitHub Pages: https://fusion.actuallab.net/
• Documentation is a work in progress, and you're welcome to contribute!

Fixed

• Multiple issues related to RPC rerouting
• RpcCommandHandler repeatedly sending commands to the server
• A new bug in FrameDelayers.MustDelay method (introduced in late v11.3.X), which effectively disabled RPC frame delaying
• Use of incorrect Handshake index on some reconnection attempts – the issue was rare, but once it happened, it was blocking RPC reconnects for ~5 min.
• Task.Result usage is replaced with .GetAwaiter().GetResult() everywhere (it's faster and safer)
• $csys.Invalidate calls (remote invalidation notifications) now trigger Computed.Invalidate(immediately: true) call rather than just Computed.Invalidate(), which eliminates double delay for RPC compute methods that use invalidation delay
• Various minor fixes.

Tests

• WebTestHelpers.GetUnusedLocalUri helper method in ActualLab.Testing
• CapturingLogger and CapturingLoggerProvider in ActualLab.Testing
• Improved cancellation and timeout handling in RPC tests
• Added benchmark tests for Task.Result vs Task.GetAwaiter().GetResult()
• Added CapturingLogger unit test

11.0.15+ec823882

Release date: 2025-11-05

Changed

• Returned back IMutableState.Value setters (they were removed in v11.0.8)
• Added "Must" prefix to RpcDefaultCallTracer.TraceInbound and TraceOutbound flags for consistency with bool field naming rules.

Fixed

• Adjusted RpcDefaultDelegates.CallTracerFactory to enable full tracing for server (RuntimeInfo.IsServer), and no tracing for the client.

Changed in Samples

• TodoApp: Updated Aspire SDK to version 9.5.2 and centralized its version configuration
• TodoApp: Temporarily disabled Microsoft Account authentication (the current credentials are expired).

11.0.8+1fd1d61afb

Release date: 2025-11-02

Breaking Changes

• Revamped RpcServiceBuilder API. Its new Inject method "injects" a service described by RpcServiceBuilder into IServiceCollection
• RpcBuilder and FusionBuilder's AddXxx methods now rely on RpcServiceBuilder.Inject
• IMutableState and MutableState lost Value setter; use Set(...) methods to set it. Invalidation path tracking is the reason of this change: new .Set(...) overloads use [CallerFilePath], [CallerMemberName], and [CallerLineNumber] to propagate the origin of change to the invalidation logic, and there is no way to achieve the same with .Value property. I may end up returning it with [Obsolete] attribute though.
• Renamed IHasIsDisposed to IHasDisposeStatus
• Removed RpcServiceMode.DistributedPair mode and related logic (Distributed mode offers more anyway)
• Removed RpcSwitchInterceptor;

Added

• Quite useful ComputedOptions.ConsolidationDelay and related APIs (see Releases chat on https://voxt.ai/chat/s-1KCdcYy9z2-uJVPKZsbEo for details)
• Invalidation path tracking: InvalidationSource, Invalidation.TrackingMode, and other changes
• Computed.ToString(InvalidationSourceFormat) is Computed.ToString(), but with invalidation path info
• FusionMonitor is now capable of gathering invalidation path statistics.

Changed

• More readable output of MethodInfo.ToShortString() is now used to dump compute service methods

Fixed

• Another issue in RpcCallTracker.TryReconnect that may block stateful reconnect
• A couple places in Fusion RPC stack where Computed.Invalidate(immediately: false) was used instead of Computed.Invalidate(immediately: true)
• Incorrect use of Sampler-s in FusionMonitor: missing "not" was making it to sample where it had to skip, and vice versa 😦 That's why statistics was typically 7x exaggerated there (the probability of logging EveryNth(8) is 7/8, i.e. close to 1, but it was reporting it as 1/8).

10.6.38+254f4ef775

Release date: 2025-10-28

Changed

• Breaking: Replaced RpcCallRouteOverride with RpcCallOptions, expect more changes in this area
• Removed RpcNonRoutingInterceptor and related infrastructure; RpcRoutingInterceptor does a bit more and equally fast
• Updated CODING_STYLE.md

Fixed

• RpcCallTracker.TryReconnect - IncreasingSeqCompressor.Serialize was getting a potentially misordered sequence making fast (stateful) reconnect impossible, though stateless reconnect still worked in these cases
• Renamed CompleteAsync class to Completion to correct a previous wrong rename
• RpcRoutingInterceptor now properly reroutes local calls as well

Tests

• Added new MeshRpc tests; will be extending them in the near future
• Refactored FusionTestBase descendants to move DI of test-specific services to specific tests
• Reorganized DB model classes under DbModel namespace in tests

10.6.18+af2a52320f

Fixed

• ActualLab.Generators now add #if-s suppressing [UnconditionalSuppressMessage] and [ModuleInitializer] for .NET Framework 4.7.2 and .NET Standard 2.0.

10.6.16+d0431715b7

Release date: 2025-10-27

Changed

• Renamed ChannelReadMode to WebSocketChannelReadMode
• Removed IChannelWithReadMode, updated WebSocketChannel to implement IAsyncEnumerable directly.

Performance

• Adjusted BoundedChannelOptions for ReadChannel (120→100) and WriteChannel (120→500) in WebSocketChannel to optimize buffering behavior

Infrastructure

• Added UnbufferedPushSequence<T> for unbuffered async data streaming
• Added [UnsafeAccessor]-based helpers for AsyncTaskMethodBuilder<T> in AsyncTaskMethodBuilderExt.

Documentation

• Replaced .instructions.md with updated AGENTS.md and CODING_STYLE.md

10.6.4

Release date: 2025-10-25

Breaking Changes

• Breaking: Removed FusionDefaults and FusionMode types. Use RuntimeInfo.IsServer, ComputedRegistry.Settings, and Timeouts.Settings instead.
• Breaking: Removed RpcMode type. Use RuntimeInfo.IsServer instead.
• Breaking: ComputedRegistry.Instance is gone, the whole class is now static
• Breaking: Timeouts and IGenericTimeoutHandler are moved to ActualLab.Time namespace.
• Breaking: reworked OperationEvent API enabling events with quantized delay. Such events have Uuid, which includes its DelayUntil value, and have quantized DelayUntil. So you can use them to implement reliable throttling for such activities as post-change indexing or AI processing
• Breaking: IHasDelayUntil interface is removed, and thus its support in OperationEvent handling logic.
• Breaking: .NET Framework 4.7.1 target is replaced with .NET Framework 4.7.2

Added

• .NET 10 RC2 support
• allowInconsistent flag in Computed/AnyState/ComputedSource.Use() and .UseUntyped() methods. Get the value even if it's inconsistent; when called inside a compute method, instantly invalidates the newly created computed if an inconsistent dependency gets captured.
• bool Operation.MustStore property allowing to disable the operation log entry creation; this is useful when you're sure you don't need distributed invalidation for the current operation - e.g., you know that only the local machine is responsible for exposing modified data. When MustStore is false, a DbEvent (in Processed state) is created instead of an DbOperation entry to verify commit in case of commit failure.
• OperationScope.CompletionHandlers allowing to register operation completion handler right inside the command handler
• RpcCallRouteOverride type allowing to override outgoing RPC call routing (e.g., set destination peer)
• Moment.Floor, Moment.Ceiling, Moment.Round, and Moment.Convert methods; Moment.Ceiling is used to quantize delayed events.

Changed

• Moved command routing logic to RpcRoutingCommandHandler
• Renamed ComputeServiceCommandCompletionInvalidator to InvalidatingCommandCompletionHandler
• Improvements in RetryPolicy / IRetryPolicy, including exception filters
• ArgumentListG*<...> is now IL/AOT-trimmable via ArgumentList.AllowGenerics feature switch

Fixed

• Native AOT support in .NET 10
• A bug in ComputeRegistry that could cause ComputedRegistry to expose a wrong Computed due to a race between ComputedRegistry.Get and ComputedRegistry.Register. If Get gets paused between a moment it read a handle and resolved its Target, the handle with the same IntPtr value might get re-allocated. This is extremely rare, but nevertheless, we saw this happening in production.
• The identical bug in RpcObjectTracker (it's used to track RpcStream-s).
• IDelegatingCommand now "implements" IOutermostCommand (it was supposed to, but didn't)
• StatefulComponent.StateChanged handler now suppresses ExecutionContext flow
• Bug in RpcSystemCallSender.Ok breaking RpcStream serialization in call results
• Bug in RpcStream enumerator
• Proper framework version check in CpuTimestamp for .NET 10 WASM
• Removed Microsoft.Extensions.Http reference from ActualLab.Rpc

Performance

• WebSocketChannel.ReadMode and corresponding option enabling unbuffered reads without use of Reader (which is backed by its own Channel). This option alone improves RPC performance by 5%.
• Use CancellationToken.None in WebSocket operations in WebSocketChannel without sacrificing cancellation support (WebSocket is properly disconnected on cancellation now)
• RpcStream now uses Memory<byte> instead of byte[] for its buffer.
• Use of Unsafe.As<T>(x) instead of (T)x in a few key places.
• Improvements in key Fusion components, including ComputedRegistry, Computed, and ComputedState,
• Improvements in Blazor components, including StatefulComponentBase and ComputedStateComponentBase
• Improvements in infrastructure components, including ArgumentList, FixedArray, AsyncLock, and AsyncLockSet.

Infrastructure

• Added WeakReferenceSlim (currently unused)
• Added TaskExt.NeverEnding(CancellationToken) helper
• Added FixedTimerSet and ConcurrentFixedTimerSet
• Improved CancellationTokenSource-based timeout handling code across the board
• Improved tests.

Documentation

• Added .instructions.md (like AGENTS.md) for agent rules
• Finalized Part01, added examples for Computed<T>.When() and Changes() methods.

Earlier Versions

For changes in earlier versions, please refer to the git commit history or see "Fusion/🎉Releases" on Voxt.ai: https://voxt.ai/chat/s-1KCdcYy9z2-uJVPKZsbEo