ActualLab.Fusion

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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.

To track updates in real time, see "Fusion/🎉Releases" on Voxt.ai.

12.1.114+a74e74b2 | npm: 12.1.115 ​

Release date: 2026-03-18

Added ​

  • RpcSerializableAttribute ([RpcSerializable]) — marks abstract types as non-polymorphic for RPC serialization, allowing the underlying serializer's union support ([JsonDerivedType], [MemoryPackUnion], [Union]) to handle type discrimination instead of RPC's TypeRef wrapping
  • RpcSerializationFormatException and RpcWebSocketCloseCode.UnsupportedFormat — better error handling when client requests a serialization format unknown to the server

Documentation ​

  • Added "Polymorphic Serialization" section to RPC Serialization docs covering [RpcSerializable] usage

Tests ​

  • Added tests for [RpcSerializable] with NonPolymorphicBase hierarchy, including RpcStream scenarios
  • Added tests for unsupported serialization format handling in RpcWebSocketTest

12.1.107+fe771590 | npm: 12.1.100 ​

Release date: 2026-03-17

Added ​

  • SharedFloatPool and SharedDoublePool in ArrayPools (ActualLab.Core) — shared array pools for float and double types

Changed ​

  • Removed unmanaged constraint from NonPoolingArrayPool<T>, allowing it to work with any type

Tests ​

  • Added unit tests for NonPoolingArrayPool<T> in ActualLab.Tests

12.1.102+00807c35 | npm: 12.1.100 ​

Release date: 2026-03-17

Fixed ​

  • AsyncTaskMethodBuilderExt.FromTask didn't work — introduced GenericAccessors<T> to workaround unsafe accessors for generics due to runtime limitations; refactored both generic and untyped FromTask variant

Tests ​

  • Added unit tests for FromTask and GenericFromTask to validate functionality and correctness

12.1.100+b7edfdd5 | npm: 12.1.100 ​

Release date: 2026-03-16

Breaking Changes (.NET) ​

  • Removed IsReconnectable property from IRpcSharedObject — replaced by AllowReconnect on IRpcObject
  • RpcStream.New<T>() factory method parameter renamed from isReconnectable to allowReconnect

Added (.NET) ​

  • AllowReconnect property on IRpcObject interface — controls whether an RPC object (stream) should reconnect or immediately disconnect when a peer connection drops
  • RpcStream<T> now serializes AllowReconnect as a 5th field in the wire format (backward-compatible: old 4-field format defaults to AllowReconnect = true)
  • Server-side RpcSharedStream rejects reconnect attempts for AllowReconnect = false streams and auto-disposes them on disconnect
  • RpcRemoteObjectTracker disconnects non-reconnectable remote objects on peer disconnect

Added (TypeScript) ​

  • TypeScript RPC: allowReconnect support in RpcStream, RpcStreamSender, parseStreamRef(), and RpcRemoteObjectTracker

Documentation ​

  • Updated RpcStream docs to reflect AllowReconnect replacing IsReconnectable

Tests ​

  • Added NoReconnectStreamTest and NoReconnectStreamDisconnectTest (.NET)
  • Added TypeScript unit tests for allowReconnect in RpcStream, RpcStreamSender, and parseStreamRef
  • Added TypeScript end-to-end tests for allowReconnect = false disconnect behavior
  • Cross-language E2E test (StreamNoReconnect) verifying AllowReconnect = false behavior between TypeScript client and .NET server

12.1.98+62afac4f | npm: 12.1.69 ​

Release date: 2026-03-10

Added ​

  • CpuTimestampBasedVersionGenerator — a new VersionGenerator<long> based on CpuTimestamp ticks, useful for in-process only high-resolution monotonic versioning
  • IState.GetExistingComputed() method (it was available via ComputedInput, but wasn't a part of IState)

Changed ​

  • Renamed Versioning/Providers/ folder to Versioning/Generators/ and moved ClockBasedVersionGenerator to ActualLab.Versioning namespace

Fixed ​

  • Stale state bug in ComputedState during Recompute: concurrent invalidation could target an already-replaced computed instance, causing the state to miss updates. StateExt.Invalidate and Recompute now use GetExistingComputed() instead of Snapshot.Computed to address that

Documentation ​

  • Added Standalone Authentication guide — explains how to extract Fusion's auth system into your own project for full control and simpler code

12.1.89+ee8734c3 | npm: 12.1.69 ​

Release date: 2026-03-04

Breaking Changes ​

  • ShardMap<TNode> constructor no longer accepts Func<TNode, IEnumerable<int>> for custom hashing — use ShardMapBuilder parameter instead
  • Default shard mapping algorithm changed from greedy to rendezvous hashing — existing shard assignments will differ after upgrade
  • DbLogReader.ProcessBatch return type changed from Task<int> to Task<Moment> — subclasses must update their override signatures

Added ​

  • ShardMapBuilder abstraction with two built-in strategies: GreedyShardMapBuilder (old behavior) and RendezvousShardMapBuilder (new default) for optimal minimal reallocation when nodes change
  • DbEventLogReader.GetMinDelayUntil for precise delayed event scheduling — log reader now sleeps until the next delayed entry instead of polling on a fixed interval

Changed ​

  • Improved log processing queries in DbEventLogReader: it uses == LogEntryState.New filter and OrderBy(DelayUntil) for more reliable index utilization

Fixed ​

  • Operation event processing now schedules precisely based on the earliest pending entry's DelayUntil, avoiding unnecessary polling
  • DbLogReader.ProcessNewEntries reworked to support precise sleep-until scheduling based on ProcessBatch return value

Documentation ​

  • Replaced Mermaid diagrams with SVG images in architecture docs
  • Added animated SVG diagrams for distributed scaling, dependency graphs, caching, and recomputation
  • Added TypeScript port documentation section

Tests ​

  • Added ShardMapBuilder comparison tests (greedy vs rendezvous)
  • Added delayed event processing test with precise scheduling verification

12.1.69+10006328 | npm: 12.1.69 ​

Release date: 2026-02-22

Added (TypeScript) ​

  • RpcStream support in TypeScript RPC client — full streaming with batching, reconnection, and end-of-stream handling
  • Stream performance test (StreamInt32) for benchmarking TypeScript RPC stream throughput
  • RpcType.stream return type in TypeScript service definitions

Changed (TypeScript) ​

  • TypeScript RPC method definitions now use returns: RpcType.noWait instead of a noWait boolean flag, improving API consistency
  • Simplified wire argument count calculations in TypeScript by assuming CancellationToken slot as default (removed ctOffset option)

Tests (TypeScript) ​

  • Added comprehensive RpcStream unit tests in TypeScript covering batching, reconnection, multiple enumeration, and disposal
  • New stream performance benchmarks

12.1.61+045f13f0 ​

Release date: 2026-02-18

Added ​

  • "No polymorphism" JSON serialization formats (json5np, njson5np) for strict non-polymorphic RPC serialization
  • RpcLimits.PrematureDisconnectTimeout for improved connection backoff logic

Changed ​

  • Connection retry logic now uses ConnectionAttemptIndex instead of TryIndex with handling for premature connection closures
  • Default serialization format for RpcClientPeer (TypeScript) changed to json5np

Documentation ​

  • RpcLimits class documentation

Tests ​

  • Added TypeScript RPC performance harness

12.1.51+8e1051d0 ​

Release date: 2026-02-17

Added ​

  • IsSynchronized and WhenSynchronized methods on State, ComputedState, and MutableState for streamlined synchronization checks
  • IState.IsSynchronized(), IState.WhenSynchronized(), and IState.Synchronize() extension methods in StateExt
  • KeepProcessedItems and KeepDiscardedItems retention settings in DbLogReaderOptions for fine-grained control over log item lifecycle

Tests ​

  • Added TypeScript RPC reconnection scenario tests (both unit and E2E against .NET server)

12.1.41+718a0325 ​

Release date: 2026-02-14

Added ​

  • Work in progress: TypeScript Fusion client. Core abstractions, compute methods, ComputedState, MutableState, invalidation, and fusion-react package with React bindings.
  • React-based "Todo v3" page in the TodoApp sample showing how to use the client.

Fixed ​

  • Missing HasName(...) calls in FusionBuilder for AddClient, AddServer, and AddDistributedService methods
  • Proper ArgumentData formatting in RpcInboundCall for improved readability

Infrastructure ​

  • Added TypeScript monorepo under ts/ with @actuallab/core, @actuallab/rpc, @actuallab/fusion, and @actuallab/fusion-rpc packages
  • Integrated TypeScript build pipeline into the Todo sample Host project via MSBuild targets

12.1.14+28a7e73e ​

Release date: 2026-02-11

Fixed ​

  • RPC WebSocket disconnect detection was delayed by ~50 seconds instead of being instant. When the server shut down, RpcPeer.OnRun awaited maintainTasks in a finally block before cancelling readerTokenSource, so SharedObjects.Maintain() kept running its keep-alive check loop for up to 55s (KeepAliveTimeout) before detecting the timeout. The fix moves the readerTokenSource cancellation before the maintainTasks await.

12.1.12+0475b1ca ​

Release date: 2026-02-11

Breaking Changes ​

  • mempack6(c) / msgpack6(c) binary protocols no longer persist message size, fixing the compatibility issue with pre-v12 protocols. This seems to be the very first release issue attributed to Claude Code: it somehow concluded the size has to be persisted while migrating WebSocketChannel to RpcWebSocketTransport API, but in reality is wasn't (the code branch persisting the size was disabled via other logic). Sorry we caught this just now: the issue is there for two weeks already (from v12.0.9).

Fixed ​

  • Option<T> now always uses explicit MessagePackFormatter instead of conditional MessagePackObject(true) with SuppressSourceGeneration on .NET 8+, fixing serialization consistency across target frameworks

Tests ​

  • Added conditional flags (UseSystemJsonSerializer, UseNewtonsoftJsonSerializer, UseMessagePackSerializer, UseMemoryPackSerializer) in SerializationTestExt for selectively enabling/disabling specific serializers in tests
  • Added serialization round-trip tests for DbUser, DbChat, DbMessage

12.1.4+7b59e831 ​

Release date: 2026-02-07

Added ​

  • New ActualLab.Serialization.NerdbankMessagePack package – optional Nerdbank.MessagePack serialization support. You can also register new nmsgpack6/nmsgpack6c RPC formats by calling RpcNerdbankSerializationFormat.Register() at startup

Fixed ​

  • ApiNullable<T>, ApiNullable8<T>, ApiOption<T> now always use explicit MessagePackFormatter instead of conditionally using MessagePackObject(true) on .NET 8+

Documentation ​

12.0.85+53469221 ​

Release date: 2026-02-06

Breaking Changes ​

  • CpuTimestamp.PositiveInfinity and CpuTimestamp.NegativeInfinity renamed to MaxValue and MinValue
  • CoarseCpuClock removed as mostly useless, use CpuClock instead;
  • MomentClockSet no longer has a CoarseCpuClock property and its constructor no longer accepts a coarseCpuClock parameter

Changed ​

  • RPC keep-alive tracking now uses Moment (wall-clock time) instead of CpuTimestamp, fixing reliability issues on Unix systems where CPU sleep could stall timestamps

Fixed ​

  • IRpcSharedObject.LastKeepAliveAt changed from CpuTimestamp to Moment – CpuTimestamp could freeze during CPU sleep on Unix, causing incorrect keep-alive tracking
  • RpcHub.Clock renamed to RpcHub.SystemClock (now uses SystemClock instead of CpuClock) by the same reason

Documentation ​

  • XML summary descriptions added (auto-generated with Claude Code) to all public types and members
  • Added Api-Index.md – a comprehensive type catalog listing all public types across ActualLab.Fusion NuGet packages

12.0.76+7e668fb2 ​

Release date: 2026-02-04

Fixed ​

  • RpcRerouteException handling code no longer attempts to reroute during disposal of IServiceProvider, preventing potential rerouting cycles during shutdown

12.0.70+1775d374 ​

Release date: 2026-02-03

Fixed ​

  • RpcStream with IsReconnectable == false fails right on the first enumeration rather than after the reconnection attempt

12.0.65+68251969 ​

Release date: 2026-02-03

Added ​

  • RpcStream.IsReconnectable property – controls whether a stream can be reconnected after disconnection; true by default, set to false to make reconnection attempts fail with RpcStreamNotFoundException
  • RpcStreamNotFoundException – new exception thrown when attempting to reconnect a non-reconnectable or expired stream

Tests ​

  • Added FlakyTest.XUnit dependency for marking time-dependent tests as flaky
  • Marked timing-sensitive tests (ConcurrentTimerSetTest, ConcurrentFixedTimerSetTest) with [FlakyFact] attribute for improved test reliability

12.0.60+9bb19676 ​

Release date: 2026-02-01

Breaking Changes ​

  • IOperationEventSource.ToOperationEvent() signature changed: now accepts IServiceProvider parameter instead of no parameters (intermediate version accepted IOperationScope)
  • MemoryBuffer<T> replaced with RefArrayPoolBuffer<T> – migrate by updating type references and using ArrayPool<T> constructor parameter
  • ArrayPoolBuffer<T>, ArrayOwner<T>, and BufferWriterExt moved from ActualLab.IO to ActualLab.Collections namespace

Added ​

  • RefArrayPoolBuffer<T> – a ref struct buffer backed by ArrayPool<T> with configurable pool and clearing behavior
  • TimeSpan?.ToShortString() extension method with customizable null fallback value
  • ArrayPools static class providing common array pool instances

Changed ​

  • ArrayPoolBuffer<T> enhanced with additional constructor overloads and ToArrayOwner() method

Fixed ​

  • AsyncTaskMethodBuilder extension methods now check task completion state before accessing Task.Exception, preventing potential inner exceptions

Tests ​

  • Improved ActualLab.Rpc test stability with positive maxWaitTime validation
  • Better test database isolation in FusionTestBase

Documentation ​

  • Added BatchSize property documentation to RpcStream flow control section
  • Added Docker benchmark results to performance documentation

Infrastructure ​

  • Added Clean.cmd script for cleaning build artifacts on Windows and Unix platforms

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 ​

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.

Key Changes in 2025 ​

  • Documentation website launch – https://fusion.actuallab.net/ with VitePress, migrated Parts 01–13 from the old tutorial, video TOCs, GitHub Pages deployment workflow.
  • RPC routing and distributed services overhaul – new RpcLocalExecutionMode, IRpcMiddleware stack (replacing IRpcInboundCallPreprocessor), RpcRoutingCommandHandler, RpcCallOptions, RpcServiceBuilder.Inject, and much more robust rerouting logic for shard-aware distributed services.
  • Invalidation path tracking and consolidation – InvalidationSource, Invalidation.TrackingMode, ComputedOptions.ConsolidationDelay for grouping rapid invalidations, and FusionMonitor invalidation path statistics.
  • .NET 10 support.

Key Changes in 2024 ​

  • RPC serialization formats revamp – introduced mempack2/msgpack2 binary formats with compact method name hashes (mempack2c/msgpack2c), serialization format negotiation, and zero-copy serialization in the transport layer. RpcByteMessageSerializer and FastRpcMessageByteSerializer brought significant throughput gains.
  • OperationEvent introduction – event handling with DbEventTestBase,
  • .NET 9 support and Native AOT – full .NET 9 support (RC1 → release), proxy generators updated with AOT-compatible code generation (ProxyCodeKeeper, KeepCode), and [UnsafeAccessor]-based helpers for internal reflection.
  • .NET 9 support.

Key Changes in 2023 ​

  • ActualLab.Rpc – new RPC framework – built from scratch starting April 2023, replacing the old Replica/Publisher/Replicator bridge with a modern WebSocket-based RPC system. Includes RpcPeer, RpcStream, RpcHub, call routing, reconnection, shared object tracking, and binary serialization.
  • Compute caching (client-side) – ClientComputeMethodFunction improvements and RpcCacheKey for caching RPC compute method results on the client side.
  • Blazor improvements – ComputedState.Options.TryComputeSynchronously for faster initial rendering, improved ComputedStateComponent, BlazorCircuitContext enhancements, and RpcPeerStateMonitor for connection state UI.
  • Rename from Stl.* to ActualLab.* – all NuGet packages, namespaces, and project files renamed in December 2023 (e.g., Stl.Fusion → ActualLab.Fusion, Stl.CommandR → ActualLab.CommandR).
  • .NET 8 support – full .NET 8 support including [UnsafeAccessor] usage, IL trimming markup, [DynamicDependency] annotations, and AOT-related preparations.

Key Changes in 2022 ​

  • Roslyn proxy generators – Stl.Generators package with ProxyGenerator for compile-time proxy generation via Roslyn source generators, replacing runtime Castle DynamicProxy for [ComputeMethod] and command service interception.
  • .NET 7 support – added .NET 7 targeting (RC2 → release), updated framework dependencies, and CI workflows.

Key Changes in 2021 ​

  • Binary serialization – initial MessagePack serialization support, IByteSerializer/ITextSerializer abstractions, and TypeDecoratingSerializer for polymorphic serialization. Refactored text serializers from ITextWriter/ITextReader to simpler Read/Write overloads.
  • OpenTelemetry support – initial System.Diagnostics.DiagnosticSource integration with ActivitySource-based tracing for compute methods and command handlers.
  • .NET 6 support.

Key Changes in 2020 ​

Year of project inception.

  • Fusion core – established the foundational Computed<T>, ComputeMethod, State/MutableState/LiveState abstractions, ComputedRegistry, automatic dependency tracking, and invalidation pipeline.
  • CQRS / CommandR – Stl.CommandR command processing pipeline with ICommand<T>, CommandContext, CommandHandler, and middleware pipeline for orchestrating side-effect-producing operations alongside Fusion's read model.
  • Replica services and WebSocket bridge – ReplicaService, Publisher/Replicator bridge over WebSockets, SubscriptionProcessor for managing live subscriptions.
  • Entity Framework integration – Stl.Fusion.EntityFramework with DbOperationScope, DbAuthService, DbSessionInfo, early multi-tenancy support, and PostgreSQL/MySQL/SQL Server provider compatibility.
  • .NET 5 and multi-targeting – migrated from .NET Core 3.1 to .NET 5 with multi-targeting.