NullReferenceException during state change

[nordic81]

Hi,
I tried the CircuitBreaker from your nuget package and encountered a NullReferenceException instead of a CircuitBreakerTrippedException during the state change from "normal" to "tripped".

I think the exception occurs because the statemachine property in the states settings is null, and i think this is because of an initialization problem: The CircuitBreaker's constructor initialized the parameters with an uninitialized statemachine, so this property will ever be null.

[andywilsonuk]

Hi nordic81,

I think you are constructing it like this:
new CircuitBreaker(null);

when it needs to be like this:
new CircuitBreaker(new CircuitBreakerSettings());

If that's the case then I can make a change so that it uses default settings if you pass a null CircuitBreakerSettings object.

Cheers
Andy

[nordic81]

Hi Andy,
I’ve been initializing the CircuitBreaker with an instance of CircuitBreakerSettings.

When I view the sourcecode on GitHub, I can see that the Constructor of the CircuitBreaker class instantiates a new CircuitBreakerStateParameters object with a not-yet-intialized state machine (CircuitBreaker.cs, line 33). So this state machine property within the Parameters will always be null, but this property is accessed
In CircuitBreakerStateNormal.TransitionToTripped() (CircuitBreakerStateNormal.cs, line 65) which provokes the NullReferenceException.

I may be wrong, though.

Kind regards
Norbert

[andywilsonuk]

Hi Norbert,

You were absolutely right, I added an Integration Test which demonstrated the issue and I've updated the source and nuget package

I don't actually use this version of the Circuit Breaker at the moment and I hadn't spotted the issue so thanks for letting me know.

Andy