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Make Dispatcher.Yield use the current dispatcher #20956

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Merged
MrJul merged 1 commit into from
Mar 20, 2026
+31 −49
Merged

Make Dispatcher.Yield use the current dispatcher #20956

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5 changes: 1 addition & 4 deletions src/Avalonia.Base/Threading/Dispatcher.Invoke.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -737,9 +737,6 @@ public static DispatcherPriorityAwaitable Yield() =>
/// </exception>
public static DispatcherPriorityAwaitable Yield(DispatcherPriority priority)
{
// TODO12: Update to use Dispatcher.CurrentDispatcher once multi-dispatcher support is merged
var current = UIThread;
current.VerifyAccess();
return UIThread.Resume(priority);
return CurrentDispatcher.Resume(priority);
}
}
75 changes: 30 additions & 45 deletions tests/Avalonia.Base.UnitTests/DispatcherTests.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -512,102 +512,87 @@ async Task Test()


[Fact]
public async Task DispatcherResumeContinuesOnUIThread()
public async Task DispatcherResumeContinuesOnCurrentThread()
{
using var services = new DispatcherServices(new SimpleControlledDispatcherImpl());

var tokenSource = new CancellationTokenSource();
var workload = Dispatcher.UIThread.InvokeAsync(
var dispatcher = Dispatcher.CurrentDispatcher;

var workload = dispatcher.InvokeAsync(
async () =>
{
Assert.True(Dispatcher.UIThread.CheckAccess());
Assert.True(dispatcher.CheckAccess());

await Task.Delay(1).ConfigureAwait(false);
Assert.False(Dispatcher.UIThread.CheckAccess());
Assert.False(dispatcher.CheckAccess());

await Dispatcher.UIThread.Resume();
Assert.True(Dispatcher.UIThread.CheckAccess());
await dispatcher.Resume();
Assert.True(dispatcher.CheckAccess());

tokenSource.Cancel();
});

Dispatcher.UIThread.MainLoop(tokenSource.Token);
dispatcher.MainLoop(tokenSource.Token);
}

[Fact]
public async Task DispatcherYieldContinuesOnUIThread()
public async Task DispatcherYieldContinuesOnCurrentThread()
{
using var services = new DispatcherServices(new SimpleControlledDispatcherImpl());

var tokenSource = new CancellationTokenSource();
var workload = Dispatcher.UIThread.InvokeAsync(
async () =>
{
Assert.True(Dispatcher.UIThread.CheckAccess());

await Dispatcher.Yield();
Assert.True(Dispatcher.UIThread.CheckAccess());

tokenSource.Cancel();
});

Dispatcher.UIThread.MainLoop(tokenSource.Token);
}

[Fact]
public async Task DispatcherYieldThrowsOnNonUIThread()
{
using var services = new DispatcherServices(new SimpleControlledDispatcherImpl());
var dispatcher = Dispatcher.CurrentDispatcher;

var tokenSource = new CancellationTokenSource();
var workload = Dispatcher.UIThread.InvokeAsync(
var workload = dispatcher.InvokeAsync(
async () =>
{
Assert.True(Dispatcher.UIThread.CheckAccess());
Assert.True(dispatcher.CheckAccess());

await Task.Delay(1).ConfigureAwait(false);
Assert.False(Dispatcher.UIThread.CheckAccess());
await Assert.ThrowsAsync<InvalidOperationException>(async () => await Dispatcher.Yield());
await Dispatcher.Yield();
Assert.True(dispatcher.CheckAccess());

tokenSource.Cancel();
});

Dispatcher.UIThread.MainLoop(tokenSource.Token);
dispatcher.MainLoop(tokenSource.Token);
}

[Fact]
public async Task AwaitWithPriorityRunsOnUIThread()
public async Task AwaitWithPriorityRunsOnCurrentThread()
{
static async Task<int> Workload()
static async Task<int> Workload(Dispatcher dispatcher)
{
await Task.Delay(1).ConfigureAwait(false);
Assert.False(Dispatcher.UIThread.CheckAccess());
Assert.False(dispatcher.CheckAccess());

return Thread.CurrentThread.ManagedThreadId;
}

using var services = new DispatcherServices(new SimpleControlledDispatcherImpl());

var tokenSource = new CancellationTokenSource();
var workload = Dispatcher.UIThread.InvokeAsync(
var dispatcher = Dispatcher.CurrentDispatcher;

var workload = dispatcher.InvokeAsync(
async () =>
{
Assert.True(Dispatcher.UIThread.CheckAccess());
Task taskWithoutResult = Workload();
Assert.True(dispatcher.CheckAccess());
Task taskWithoutResult = Workload(dispatcher);

await Dispatcher.UIThread.AwaitWithPriority(taskWithoutResult, DispatcherPriority.Default);
await dispatcher.AwaitWithPriority(taskWithoutResult, DispatcherPriority.Default);

Assert.True(Dispatcher.UIThread.CheckAccess());
Task<int> taskWithResult = Workload();
Assert.True(dispatcher.CheckAccess());
Task<int> taskWithResult = Workload(dispatcher);

await Dispatcher.UIThread.AwaitWithPriority(taskWithResult, DispatcherPriority.Default);
await dispatcher.AwaitWithPriority(taskWithResult, DispatcherPriority.Default);

Assert.True(Dispatcher.UIThread.CheckAccess());
Assert.True(dispatcher.CheckAccess());

tokenSource.Cancel();
});

Dispatcher.UIThread.MainLoop(tokenSource.Token);
dispatcher.MainLoop(tokenSource.Token);
}

private class AsyncLocalTestClass
Expand Down