CircuitBreaker will stuck in HALF_OPEN when the last request throw ignored exception

When the last request during HALF_OPEN state throws exception which set ignored, the CircuitBreaker will stuck in HALF permanently. (found in 0.15.0 version)

see code in : io/github/resilience4j/circuitbreaker/internal/CircuitBreakerStateMachine.java

private void handleThrowable(long durationInNanos, Predicate<Throwable> recordFailurePredicate, Throwable throwable) {
        if (recordFailurePredicate.test(throwable)) {
            LOG.debug("CircuitBreaker '{}' recorded a failure:", name, throwable);
            publishCircuitErrorEvent(name, durationInNanos, throwable);
            stateReference.get().onError(throwable);
        } else {
            publishCircuitIgnoredErrorEvent(name, durationInNanos, throwable);
        }
    }

If the exception be ignored, the circuit breaker neither invoke the onError() method or execute releasePermission(). After that, the buffer is full and state in HALF_OPEN, means it won’t accept new requests, also won’t change to OPEN or CLOSE state. Just stuck in HALF_OPEN (See CircuitBreakerTransformer.java in https://github.com/resilience4j/resilience4j/pull/542 which resolve this bug in ratpack, but didn’t resolve this bug in core logic.)

[RobWin]

Merged. I will release it next week

[RobWin]

Yes