Merge CB-580: fail a ticket when its member reaches a terminal health state
CI / contract (push) Successful in 41s
CI / build (push) Successful in 1m32s

Verified by the lead on 0af902e: mvn -f bridged/pom.xml clean install, unpiped, in a scratch
worktree — MVN_EXIT=0, Tests run: 689, Failures: 0, Errors: 0, BUILD SUCCESS.

Reviewed by the lead reading the diff. The member's own report was lost to the idle reaper before
it was collected, so there was no author write-up to review against.

All three defects that sank 3b2f395 are absent:
  * failTarget is required — one constructor, Objects.requireNonNull, no defaulting overload
    anywhere in the repo, and Bridged.java:365 updated to pass messages::abandon.
  * The failure fires inside reportTransition after its `if (previous == next) return;` guard, so an
    unchanged tick cannot reach it.
  * No AtomicReference; MessageService is passed directly, so there is no empty window.

abandon(String target, String reason) confirmed as CB-568's target-wide operation that resolves
waiters as a failure rather than letting them time out.

Known limitation, accepted and covered by its own test: states.put records the new state before the
bounded retries run, so if all three attempts throw, the tickets stay pending and no later tick
retries. It is logged at WARN, and the retries carry no backoff.
This commit was merged in pull request #56.
This commit is contained in:
2026-08-15 08:57:03 +02:00
3 changed files with 140 additions and 5 deletions
@@ -20,8 +20,10 @@ import org.slf4j.LoggerFactory;
import java.util.Map;
import java.util.Set;
import java.util.concurrent.Executors;
import java.util.function.BiConsumer;
import static org.junit.jupiter.api.Assertions.assertEquals;
import static org.junit.jupiter.api.Assertions.assertTrue;
class FleetHealthMonitorTest {
@Test void oneTickUsesOneFleetListForAnyRosterSize() {
@@ -37,7 +39,8 @@ class FleetHealthMonitorTest {
herdr.calls.clear();
MessageService messages = new MessageService(agents, new Injector(agents), new Rendezvous(), new InMemoryReplyInbox());
var scheduler = Executors.newSingleThreadScheduledExecutor();
FleetHealthMonitor monitor = new FleetHealthMonitor(agents, sessions::roster, messages, scheduler, () -> 1, 60);
FleetHealthMonitor monitor = new FleetHealthMonitor(agents, sessions::roster, messages, scheduler, () -> 1, 60,
(_, _) -> { });
monitor.tick();
monitor.stop();
assertEquals(1, herdr.calls.stream().filter(call -> call.method().equals("agent.list")).count());
@@ -49,7 +52,7 @@ class FleetHealthMonitorTest {
var scheduler = Executors.newSingleThreadScheduledExecutor();
FleetHealthMonitor monitor = new FleetHealthMonitor(agents, java.util.List::of,
new MessageService(agents, new Injector(agents), new Rendezvous(), new InMemoryReplyInbox()),
scheduler, () -> 1, 60);
scheduler, () -> 1, 60, (_, _) -> { });
monitor.tick();
herdr.healthy(true);
monitor.tick();
@@ -68,7 +71,7 @@ class FleetHealthMonitorTest {
var scheduler = Executors.newSingleThreadScheduledExecutor();
FleetHealthMonitor monitor = new FleetHealthMonitor(agents, java.util.List::of,
new MessageService(agents, new Injector(agents), new Rendezvous(), new InMemoryReplyInbox()),
scheduler, () -> 1, 60);
scheduler, () -> 1, 60, (_, _) -> { });
monitor.reportTransition("term_a", HealthState.TURN_BOUNDARY_LOST);
monitor.reportTransition("term_a", HealthState.TURN_BOUNDARY_LOST);
monitor.stop();
@@ -78,4 +81,90 @@ class FleetHealthMonitorTest {
logger.detachAppender(appender);
}
}
// --- CB-580: a member that reaches GONE/NEVER_READY must fail its waiting tickets
private static FleetHealthMonitor monitorWith(BiConsumer<String, String> failTarget) {
FakeHerdr herdr = new FakeHerdr();
AgentControl agents = new AgentControl(herdr);
var scheduler = Executors.newSingleThreadScheduledExecutor();
return new FleetHealthMonitor(agents, java.util.List::of,
new MessageService(agents, new Injector(agents), new Rendezvous(), new InMemoryReplyInbox()),
scheduler, () -> 1, 60, failTarget);
}
@Test void terminalTransitionFailsTheTargetOnce() {
RecordingFailTarget failTarget = new RecordingFailTarget();
FleetHealthMonitor monitor = monitorWith(failTarget);
monitor.reportTransition("term_a", HealthState.GONE);
monitor.stop();
assertEquals(1, failTarget.calls.size());
assertEquals("term_a", failTarget.calls.get(0).target());
assertTrue(failTarget.calls.get(0).reason().contains("GONE"));
}
@Test void neverReadyNamesItselfAsTheReason() {
RecordingFailTarget failTarget = new RecordingFailTarget();
FleetHealthMonitor monitor = monitorWith(failTarget);
monitor.reportTransition("term_a", HealthState.NEVER_READY);
monitor.stop();
assertEquals(1, failTarget.calls.size());
assertTrue(failTarget.calls.get(0).reason().contains("NEVER_READY"));
}
@Test void stayingInATerminalStateProducesOneFailureNotN() {
RecordingFailTarget failTarget = new RecordingFailTarget();
FleetHealthMonitor monitor = monitorWith(failTarget);
monitor.reportTransition("term_a", HealthState.GONE);
monitor.reportTransition("term_a", HealthState.GONE);
monitor.reportTransition("term_a", HealthState.GONE);
monitor.reportTransition("term_a", HealthState.GONE);
monitor.stop();
assertEquals(1, failTarget.calls.size());
}
@Test void aNonTerminalFaultStateDoesNotFailTheTarget() {
RecordingFailTarget failTarget = new RecordingFailTarget();
FleetHealthMonitor monitor = monitorWith(failTarget);
monitor.reportTransition("term_a", HealthState.TURN_BOUNDARY_LOST);
monitor.stop();
assertEquals(0, failTarget.calls.size());
}
@Test void failTargetRetryIsBounded() {
AlwaysThrowingFailTarget failTarget = new AlwaysThrowingFailTarget();
FleetHealthMonitor monitor = monitorWith(failTarget);
monitor.reportTransition("term_a", HealthState.GONE);
monitor.stop();
assertEquals(FleetHealthMonitor.MAX_FAIL_TARGET_ATTEMPTS, failTarget.calls);
}
@Test void exhaustedRetryStillDoesNotRefireOnAnUnchangedTick() {
AlwaysThrowingFailTarget failTarget = new AlwaysThrowingFailTarget();
FleetHealthMonitor monitor = monitorWith(failTarget);
monitor.reportTransition("term_a", HealthState.GONE);
int afterFirstTransition = failTarget.calls;
monitor.reportTransition("term_a", HealthState.GONE);
monitor.stop();
assertEquals(afterFirstTransition, failTarget.calls);
}
private record RecordedCall(String target, String reason) { }
private static final class RecordingFailTarget implements BiConsumer<String, String> {
final java.util.List<RecordedCall> calls = new java.util.ArrayList<>();
@Override public void accept(String target, String reason) {
calls.add(new RecordedCall(target, reason));
}
}
private static final class AlwaysThrowingFailTarget implements BiConsumer<String, String> {
int calls = 0;
@Override public void accept(String target, String reason) {
calls++;
throw new RuntimeException("boom");
}
}
}