RetryWhen with max retry count

[softlion]

Retry has a retryCount option. But RetryWhen does not. It would be nice to have the same option in RetryWhen. And would make the Retry* methods more consistent.

[akarnokd]

With RetryWhen you are in full control of when to retry via the inner sequence. Just count the errors received from the error sequence.

reactive/Rx.NET/Source/tests/Tests.System.Reactive/Tests/Linq/Observable/RetryWhenTest.cs

Lines 130 to 178 in 9f2a809

	[Fact]
	public void RetryWhen_Observable_RetryCount_Basic()
	{
	var scheduler = new TestScheduler();
	var ex = new Exception();
	var xs = scheduler.CreateColdObservable(
	OnNext(5, 1),
	OnNext(10, 2),
	OnNext(15, 3),
	OnError<int>(20, ex)
	);
	var res = scheduler.Start(() =>
	xs.RetryWhen(v =>
	{
	int[] count = { 0 };
	return v.SelectMany(w =>
	{
	var c = ++count[0];
	if (c == 3)
	{
	return Observable.Throw<int>(w);
	}
	return Observable.Return(1);
	});
	})
	);
	res.Messages.AssertEqual(
	OnNext(205, 1),
	OnNext(210, 2),
	OnNext(215, 3),
	OnNext(225, 1),
	OnNext(230, 2),
	OnNext(235, 3),
	OnNext(245, 1),
	OnNext(250, 2),
	OnNext(255, 3),
	OnError<int>(260, ex)
	);
	xs.Subscriptions.AssertEqual(
	Subscribe(200, 220),
	Subscribe(220, 240),
	Subscribe(240, 260)
	);
	}

[softlion]

" Just count the errors received from the error sequence."

Sorry 1) I don't have the level to find/understand that and 2) a helper version doing that would be much simpler for everyone as this is a common requested feature.

Or maybe the philosophy here is to exclude all developpers having hard time to keep rx confidential. I don't understand.

[akarnokd]

There is nothing confidential about Rx. You simply need to work with existing tools most of the time.

Not sure what the problem is with counting the errors. I provided the example that does error counting above. Here is an excerpt:

source.RetryWhen(errors => 
         { 
             int[] count = { 0 }; 
             return errors.SelectMany(error => 
             { 
                 var c = ++count[0]; 
                 if (c == 3) 
                 { 
                     return Observable.Throw<int>(error); 
                 } 
                 return Observable.Return(1); 
             }); 
         }) 

Make this an extension method in your project with callbacks as you see fit.