Circuit breaker maxFailures documentation inaccurate

[nathanallen-toast]

In the circuit breaker docs, we see the following text under "Closed":

• When an exception occurs, it increments the failure counter.
  • When the failure counter reaches the given maxFailures threshold, the breaker moves to the Open state.

This seems to be saying that the breaker will open as soon as it sees that specified number of failures. Indeed, the example given later shows maxFailures being set to 2 (via openingStrategy = OpeningStrategy.Count(2)), and the circuit opening after seeing two failures.

However, the actual code behaves as follows:

fun Count.shouldOpen(): Boolean = failuresCount > maxFailures

fun SlidingWindow.shouldOpen(): Boolean =
        maxFailures < failures.size && failures.firstOrNull()?.plus(windowDuration)?.hasNotPassedNow() == true
}

As implemented, we require failuresCount to be greater than, rather than equal to, maxFailures for the breaker to open.

I'm happy to go in and fix this myself, but I suspect that there are users of this library who rely on this behavior. Changing the docs would be an easier solution, but that leaves OpeningStrategy with (in my opinion) a confusingly named parameter.