CB-580: fail a ticket when its member reaches a terminal health state

FleetHealthMonitor now requires a failTarget BiConsumer<String,String>
collaborator (no defaulting overload) and calls it exactly once when a
member transitions into GONE or NEVER_READY, via CB-568's idempotent
target-wide abandon() operation. The reason string names the real
terminal state. failTarget invocation retries up to
MAX_FAIL_TARGET_ATTEMPTS (3) within the same transition if it throws,
and never refires on a later tick where the state is unchanged.

Bridged.java wires messages::abandon as the production failTarget.

bridged/src/main/java/dev/ltms/bridged/Bridged.java

@@ -360,8 +360,10 @@ public final class Bridged {
         var healthScheduler = Executors.newSingleThreadScheduledExecutor(r ->
                 Thread.ofVirtual().name("bridge-health-").unstarted(r));
         if (cfg.health() != null && cfg.health().isEnabled()) {
+            // CB-580: a member found GONE/NEVER_READY must fail whatever ticket is waiting on it,
+            // through the same idempotent target-wide operation CB-516 already uses on release.
             healthMonitor = new FleetHealthMonitor(agents, sessions::roster, messages, healthScheduler,
-                    System::nanoTime, cfg.health().intervalOrDefault());
+                    System::nanoTime, cfg.health().intervalOrDefault(), messages::abandon);
             String coverage = FleetHealthMonitor.coverage(true,
                     cfg.health().notifications() != null && cfg.health().notifications().configured());
             if ("detection-only".equals(coverage)) {

bridged/src/main/java/dev/ltms/bridged/health/FleetHealthMonitor.java

@@ -12,34 +12,50 @@ import java.util.HashMap;
 import java.util.HashSet;
 import java.util.List;
 import java.util.Map;
+import java.util.Objects;
 import java.util.concurrent.ScheduledExecutorService;
 import java.util.concurrent.TimeUnit;
+import java.util.function.BiConsumer;
 import java.util.function.LongSupplier;
 import java.util.function.Supplier;
 
 /** Slow whole-fleet evidence collection. It is deliberately separate from the delivery poller. */
 public final class FleetHealthMonitor {
     private static final Logger log = LoggerFactory.getLogger(FleetHealthMonitor.class);
+
+    /** Bounded attempts to run {@link #failTarget} for one transition. Never retried tick-to-tick (CB-580). */
+    static final int MAX_FAIL_TARGET_ATTEMPTS = 3;
+
     private final AgentControl agents;
     private final Supplier<List<MemberSession>> roster;
     private final MessageService messages;
     private final ScheduledExecutorService scheduler;
     private final LongSupplier clock;
     private final long intervalSeconds;
+    private final BiConsumer<String, String> failTarget;
     private final Map<String, HealthPrior> priors = new HashMap<>();
     private final Map<String, HealthState> states = new HashMap<>();
 
     // These facts need the evidence publishers introduced by later M4 units. They are not negatives.
     private static final boolean NOT_YET_OBSERVED = false;
 
+    /**
+     * @param failTarget CB-568's idempotent target-wide failure operation (e.g. {@code messages::abandon}),
+     *                   invoked once when a member transitions into a terminal health state. Required —
+     *                   there is deliberately no defaulting overload; a caller that does not want the
+     *                   fail-tickets-on-terminal-health behavior must pass an explicit inert value (see
+     *                   {@code TestTurnTokens.inert} / {@code BridgeMcp.CapacitySource.none()} for the pattern).
+     */
     public FleetHealthMonitor(AgentControl agents, Supplier<List<MemberSession>> roster, MessageService messages,
-                              ScheduledExecutorService scheduler, LongSupplier clock, long intervalSeconds) {
+                              ScheduledExecutorService scheduler, LongSupplier clock, long intervalSeconds,
+                              BiConsumer<String, String> failTarget) {
         this.agents = agents;
         this.roster = roster;
         this.messages = messages;
         this.scheduler = scheduler;
         this.clock = clock;
         this.intervalSeconds = intervalSeconds;
+        this.failTarget = Objects.requireNonNull(failTarget, "failTarget");
     }
 
     /** Pure per-member decision seam. */
@@ -91,6 +107,34 @@ public final class FleetHealthMonitor {
         } else if (previous != null && fault(previous)) {
             log.info("fleet health member={} recovered state={} previous={}", target, next, previous);
         }
+        // CB-580: a member entering GONE/NEVER_READY must not leave its waiting tickets pending
+        // forever. Fire exactly once per transition — never on a tick where the state is unchanged,
+        // which is what made the rejected commit call abandon() once per tick for as long as a
+        // member stayed terminal.
+        if (terminal(next)) {
+            failTerminalTarget(target, next);
+        }
+    }
+
+    private void failTerminalTarget(String target, HealthState state) {
+        String reason = "fleet health: member reached terminal state " + state.name();
+        RuntimeException last = null;
+        for (int attempt = 1; attempt <= MAX_FAIL_TARGET_ATTEMPTS; attempt++) {
+            try {
+                failTarget.accept(target, reason);
+                return;
+            } catch (RuntimeException error) {
+                last = error;
+                log.warn("fleet health: failTarget attempt {}/{} failed for member={} state={}",
+                        attempt, MAX_FAIL_TARGET_ATTEMPTS, target, state, error);
+            }
+        }
+        log.warn("fleet health: giving up on failTarget for member={} state={} after {} attempts",
+                target, state, MAX_FAIL_TARGET_ATTEMPTS, last);
+    }
+
+    private static boolean terminal(HealthState state) {
+        return state == HealthState.GONE || state == HealthState.NEVER_READY;
     }
 
     private static boolean fault(HealthState state) {

bridged/src/test/java/dev/ltms/bridged/health/FleetHealthMonitorTest.java

@@ -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");
+        }
+    }
 }