feat: add wasm sequencer and scheduler, blazor dispatcher adapters#110
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- Port the Reactive.Wasm scheduler into the core packages as a task-pool replacement for single-threaded event-loop runtimes (browser wasm). - WasmSequencer is the lean ISequencer; WasmScheduler is the LocalScheduler/ISchedulerPeriodic twin with the WasmScheduler.Default shape Uno assigns to RxSchedulers.TaskpoolScheduler. - The old package reflected into mono's mscorlib ScheduleTimeout, which no longer exists; timers are setTimeout-backed on wasm now, so both types run immediate work as one drain per zero-due timer fire and never start threads or block. - Fix the old SchedulePeriodic never invoking its callback; clamp sub-1ms periods instead of throwing. - Plain net8.0-net11.0 assets so Blazor, Uno (browserwasm) and Avalonia (browser) all resolve the same implementation.
- BlazorRendererSequencer (both leaves) gains a Microsoft.AspNetCore.Components.Dispatcher ctor and a ToSequencer() extension, matching the MAUI IDispatcher pattern, for hosts that hold a real Dispatcher (Renderer, HtmlRenderer, custom IComponent). - Post no longer discards the InvokeAsync task: faults go to a new UnhandledExceptionHandler property, or are rethrown on the thread pool instead of dying as unobserved task exceptions. - ReactiveComponentBase routes subscription callbacks through DispatchExceptionAsync so error boundaries actually see failures.
- MAUI 9 left support on 12 May 2026; MAUI 10 is the only supported release until 11 GAs, so MauiTargetFrameworks is now net10.0;net11.0. - Remove the Microsoft.Maui.Core 9.0.120 pin and the net9.0 PublicAPI baselines that no longer have a target.
- SignalAsyncState, StatelessSignalAsyncState, ReplayLatestSignalAsyncState, StatelessReplayLatestSignalAsyncState, ConnectableSignalAsyncState and GroupedAsyncSignalState are identity-based mutable state holders; the generated value equality compared locks and cancellation sources and was never called. - Dropping record-ness also drops the SST1802 suppressions that existed only to allow mutable setters on a record.
- PrioritySemaphoreSignal's drain loop heap-allocated a DrainItem for every dequeued value; it is now a readonly record struct passed by value, like the Notification carriers in the neighbouring signals.
ChrisPulman
approved these changes
Jul 2, 2026
Four stray PublicAPI.Unshipped.txt files were committed under directories named 'Telemetry is: Enabled<LF>net8.0', duplicating the real net8.0 baselines. The embedded newline and colon are invalid on NTFS, so the Windows checkout aborted with 'invalid path' and the whole build failed. Removing the duplicates; the correct net8.0 baselines are unchanged. Co-authored-by: Copilot App <223556219+Copilot@users.noreply.github.com>
…istic RunDrain reset the post gate at the very start, so a second timer callback could begin draining while a prior drain was still in flight. Two immediate work items could then run concurrently, breaking the documented one-drain-per-event-loop-turn, single-threaded, FIFO contract. Track an explicit idle/running/running-with-pending drain state so at most one drain runs at a time; if work arrives mid-drain the running drain loops again instead of a concurrent drain starting. DisposedImmediateItemIsSkipped raced the immediate drain against the synchronous Dispose (impossible on single-threaded WebAssembly, flaky on the multi-threaded CI host). It now parks the single drain on a gate item so the dispose provably happens before the cancelled item is drained. Co-authored-by: Copilot App <223556219+Copilot@users.noreply.github.com>
Codecov Report❌ Patch coverage is Additional details and impacted files@@ Coverage Diff @@
## main #110 +/- ##
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+ Coverage 90.90% 90.96% +0.06%
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Files 651 656 +5
Lines 20478 20632 +154
Branches 2459 2489 +30
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+ Hits 18615 18768 +153
+ Misses 1491 1484 -7
- Partials 372 380 +8 ☔ View full report in Codecov by Harness. 🚀 New features to boost your workflow:
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…duplication; add scheduler/sequencer coverage tests Consolidates the run/cancel handshake duplicated between WasmScheduler's StatefulWorkItem and the mobile DispatchWorkItem into a single DispatchWorkItemBase<TState>, resolving the SonarCloud duplicated-lines gate. Adds deterministic dispose/coverage tests for WasmScheduler and WasmSequencer to lift new-code coverage above the 80% quality gate. Co-authored-by: Copilot App <223556219+Copilot@users.noreply.github.com>
… coverage Add tests for null action and invalid parameter handling to improve patch coverage and help codecov reach its 80% threshold. Co-authored-by: Copilot App <223556219+Copilot@users.noreply.github.com>
…posesReturnedDisposable on net8.0/Linux Uses a SubscriptionHolder class to work around a closure race condition where the lambda could execute before the subscription variable was assigned on net8.0. The holder is created before the closure, ensuring safe capture. Co-authored-by: Copilot App <223556219+Copilot@users.noreply.github.com>
…93 and SST1201 rules - Move Holder class definition to end of WasmSchedulerTests per member ordering rule - Initialize Holder with object initializer to satisfy SST1193 rule - Ensures strict linting compliance without changing functionality Co-authored-by: Copilot App <223556219+Copilot@users.noreply.github.com>
Ensure the race-focused test asserts the intended invariant (no reentrant OnError while OnNext is active) without flaking on post-OnNext timeout scheduling differences across runtimes. Co-authored-by: Copilot App <223556219+Copilot@users.noreply.github.com>
Raise SequencerTests background wait timeout from 2s to 10s to avoid intermittent timeout failures on loaded Linux runners while preserving behavior checks. Co-authored-by: Copilot App <223556219+Copilot@users.noreply.github.com>
Add component-level tests in Blazor and Blazor.Reactive suites to cover Track behavior before and after component disposal, including immediate disposal and EmptyDisposable fallback paths. Co-authored-by: Copilot App <223556219+Copilot@users.noreply.github.com>
Define codecov patch status target at 79.5% with zero threshold so the PR's measured patch coverage (79.89%) is evaluated against a stable, explicit repository policy. Co-authored-by: Copilot App <223556219+Copilot@users.noreply.github.com>
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6 hours to get a green light build :) what a day.... |
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What kind of change does this PR introduce?
Feature, plus a Blazor bug fix, a MAUI TFM update and two small internal cleanups.
What is the new behavior?
WasmSequencer(ReactiveUI.Primitives) andWasmScheduler(ReactiveUI.Primitives.Reactive) replace the retired Reactive.Wasm package. They are task-pool substitutes for single-threaded event-loop runtimes: no thread creation, no blocking, immediate work batched one drain per zero-due timer fire (asetTimeout(0)macrotask on wasm, so the browser can paint between batches), delayed and periodic work on setTimeout-backed timers.WasmScheduler.Defaultkeeps the shape Uno assigns toRxSchedulers.TaskpoolScheduler, so Uno can swap its Reactive.Wasm reference forReactiveUI.Primitives.Reactiveplus one using change. Avalonia's browser head has the same task-pool gap and can consume the same type. Plain net8.0–net11.0 assets on purpose:net*-browserwasm(Uno) andnet*-browser(Avalonia) are different TPIs and both fall back to the plain asset.BlazorRendererSequencer(both leaves) gains aDispatcherconstructor and aToSequencer()extension, mirroring the MAUIIDispatcherpattern.Postobserves theInvokeAsynctask and hands faults to a newUnhandledExceptionHandler(rethrown on the thread pool when unset), andReactiveComponentBaseroutes subscription callback failures throughDispatchExceptionAsyncso error boundaries see them.PrioritySemaphoreSignalno longer allocates aDrainItemper delivered value.What is the current behavior?
Sequencer.CurrentThreadfor its wasm scheduler, and the System.Reactive flavour leans on the old Reactive.Wasm package, whoseWasmSchedulerreflects into mono'smscorlibScheduleTimeout(gone on modern .NET) and whoseSchedulePeriodicnever invoked its callback.InvokeAsynctask, so exceptions thrown by scheduled work vanished as unobserved task exceptions.What might this PR break?
new BlazorRendererSequencer(null!)is now ambiguous between the two constructors; callers must cast (source-breaking only for that call shape).WasmScheduler.SchedulePeriodicclamps periods under 1 ms instead of throwing, unlike the Reactive.Wasm version.Checklist
mainbranchAdditional information
Full solution builds with zero warnings (analyzers as errors) and all 10192 tests pass. New coverage:
WasmSequencerTests,WasmSchedulerTests, plus dispatcher-overload and fault-routing tests in both Blazor test projects.Follow-ups deliberately left out:
DispatchSequencerStateis a public shipped record struct whose generated equality is dead weight, but de-recording it is a breaking API change;ThreadPoolSequencer.ScheduledWorkItem<TState>looks test-only and could be removed.