[Bug] DisplaySnackBarAsync does not wait for action task

[Dreamescaper]

Steps to Reproduce

Debug the following code, and tap on "Retry" button.

            bool invoked = false;
            var result = await page.DisplaySnackBarAsync("test", "Retry", async () =>
             {
                 await Task.Delay(3000);
                 invoked = true;
                 // Breakpoint1
             });

            // Breakpoint2

Expected Behavior

Retry action is awaited, Breakpoint2 is hit after Breakpoint1.

Actual Behavior

Retry action is not awaited, Breakpoint1 is hit after Breakpoint2.

Basic Information

• Version with issue: 1.1.0
• Platform Target Frameworks:
  • Android

Workaround

I did something like that:

            bool invoked = false;
            Task retryTask = null;
            var snackbarResult = await page.DisplaySnackBarAsync(text, "Retry", async () =>
            {
                async Task RetryAction()
                {
                    await Task.Delay(3000);
                    invoked = true;
                }
                retryTask = RetryAction();
                await retryTask;
            });

            if (snackbarResult)
            {
                await retryTask;
            }

[pictos]

@Dreamescaper
Could you attach a small repro?

[Dreamescaper]

Sure!
I've attached sample project. Start the project, click on "Show SnackBar" button, then click on "Action" button on snackbar.

Expected:
actionTask.Status should be RanToCompletion when execution continues after await this.DisplaySnackBarAsync.

Actual:
actionTask.Status is WaitingForActivation when execution continues after await this.DisplaySnackBarAsync.

Repro.zip

[maxkoshevoi]

I think this is by design.
await this.DisplaySnackBarAsync completes when SnackBar is no longer displayed (regardless whether SnackBar action is being executed or now), and clicking on Action - hides the SnackBar.

If you want to wait until cation completes, you'll need to write some custom code.

[Dreamescaper]

@maxkoshevoi
But what's the point of having action as Func<Task> instead of simple Action? If it's never awaited?

[maxkoshevoi]

@Dreamescaper I guess there's no point.

At the end it's just passed as an action argument:
https://github.com/xamarin/XamarinCommunityToolkit/blob/main/src/CommunityToolkit/Xamarin.CommunityToolkit/Views/Snackbar/SnackBar.android.cs#L67

[Dreamescaper]

@maxkoshevoi
https://github.com/xamarin/XamarinCommunityToolkit/blob/main/src/CommunityToolkit/Xamarin.CommunityToolkit/Views/Snackbar/SnackBar.ios.macos.cs#L119

I don't have an iOS device to check, but as far as I can see based on code, ios/macos implementation does await an action before completion.
I'm not sure what behavior is better (although I'd say that having it as Task leads to expectations that it will be awaited), but probably it should be consistent across implementations?

UPDATE: seems like same for tizen and gtk implementations - it is awaited.
On uwp/wpf it's fire-and-forget, same as on android.

[maxkoshevoi]

Good point. Updated #1357 to include fix for this. Also passed exceptions from SnackBar action into resulting task, so you can catch them in your code.