[Feature request]: allow MaxRetryAttempts=0

[verdie-g]

Is your feature request related to a specific problem? Or an existing feature?

I'm migrating from policies to resilience pipelines and I saw many of my tests failing because of

System.ComponentModel.DataAnnotations.ValidationException : The 'RetryStrategyOptions<HttpResponseMessage>' are invalid.
  Validation Errors:
    The field MaxRetryAttempts must be between 1 and 2147483647.

It seems like 0 is not accepted anymore.

The work around is to do

var pipeline = new ResiliencePipelineBuilder();
if (retryCount > 0)
{
    pipeline.AddRetry(new RetryStrategyOptions
    {
          ShouldHandle = new PredicateBuilder().Handle<Exception>(),
          MaxRetryAttempts = retryCount,
    });
}
pipeline.Build();

but it's kind of easy to miss.

In my case, the MaxRetryAttempts can come from dynamic configurations. So, changing a config to disable the pipeline by setting 0 to MaxRetryAttemps could actually break the application.

Describe the solution you'd like

When MaxRetryAttemps is set to 0, it would simply disable the retry.

Additional context

No response

[martincostello]

I would argue allowing this could have the opposite effect of allowing you to accidentally configure a non-functional retry policy while still paying for the performance overhead of a retry that will never actually retry.

I think the change for v8 makes more overall sense (retrying 0 times isn't a retry), so the correct thing to do is your "workaround" of not adding a policy that doesn't make any sense in the first place.

Either way has an advantage and a disadvantage, and I think making mis-configuration apparent/obvious is better than silent failure (i.e. no retries).

[verdie-g]

Yeah I'm fine with that idea. Just wanted to open the discussion because I'm pretty sure we'll have an incident in the future where a retry config is set to 0.

[martincostello]

I'm glad you test your policies though 😄

I've always maintained people should configure their policies and then test they behave the way they think they've configured them is correct.