Host.TryExecuteBackgroundServiceAsync logic

[WizardBrony]

This is more of a question for my understanding than an actual issue:

runtime/src/libraries/Microsoft.Extensions.Hosting/src/Internal/Host.cs

Lines 184 to 195 in 58b068b

	try
	{
	await backgroundTask.ConfigureAwait(false);
	}
	catch (Exception ex)
	{
	// When the host is being stopped, it cancels the background services.
	// This isn't an error condition, so don't log it as an error.
	if (_applicationLifetime.ApplicationStopping.IsCancellationRequested && backgroundTask.IsCanceled && ex is OperationCanceledException)
	{
	return;
	}

Is it actually possible for backgroundTask.IsCanceled to be true and ex to NOT be an OperationCanceledException?

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[ericstj]

Looks to me like Task tries to prioritize OperationCanceledException but maybe it's not guaranteed.

runtime/src/libraries/System.Private.CoreLib/src/System/Threading/Tasks/Task.cs

Lines 2774 to 2780 in c1fe87a

	// If cancellation was requested and the task was canceled, throw an
	// OperationCanceledException. This is prioritized ahead of the ThrowIfExceptional
	// call to bring more determinism to cases where the same token is used to
	// cancel the Wait and to cancel the Task. Otherwise, there's a race condition between
	// whether the Wait or the Task observes the cancellation request first,
	// and different exceptions result from the different cases.
	if (IsCanceled) cancellationToken.ThrowIfCancellationRequested();

@stephentoub in case he knows the promise, @eerhardt who added this. Maybe if the inner task itself threw an OCE but wasn't cancelled (stretching here)?