F2 (sendAsync executor catch): log when completeExceptionally returns
false, so an exception thrown after finishAsyncTask already completed
the ticket's future is no longer silently lost.
F1 (answer()'s stranded async ticket): reuse the Task reference answer()
already looked up before rendezvous.answerAsk(), instead of a second
asyncTasksByTurn lookup by turnId in finishAsyncTask. The second lookup
raced ask()'s unlocked timeout cleanup, which could forget turnId first
and leave the ticket stuck PENDING even though answer() itself returned
REPLIED. The #282 chained-ask guard is unaffected: it is still keyed on
result.outcome() == QUESTION, not on this lookup. Removed the now-unused
finishAsyncTask(String, Reply) overload.
F3 (reply()'s orphan recovery path): read orphan.turnId once instead of
twice, closing the same double-read shape fleetd #324 fixed in
finishAsyncTask.
Each fix has its own test plus a test-only race hook (mirroring #324's
finishAsyncTaskRaceHook) to force the exact interleaving deterministically.
Mutation-tested each fix by reverting it, confirming the real failure
(swallowed exception / PENDING ticket / NullPointerException), then
restoring it.
mvn clean install: Tests run: 1345, Failures: 0, Errors: 0, Skipped: 0,
BUILD SUCCESS.
The merged javadoc said a changed primary.terminal leaves a lead 'unresolved as
primary until a restart'. That over-claims. CB-532 made the pin deprecated:
identity comes from leaders:/leadScan:, and Fleetd.java:511 warns about the pin
at startup. A changed pin still needs a restart, but for the fallback nudge
destination, the deprecated identity path, and pushReminders/pushBackoffMs -
not for a lead that uses leaders:.
Also record what I measured. FleetConfig has 22 top-level components; four are
named nowhere in ConfigRef. memberCredentials and memberLoginShell are hot and
correctly absent (both read live off config.get() at spawn). health and
coordinator are undecided, not hot. 'Absent' looks the same for both kinds, and
twice now the forgotten kind hid among the correct kind.
ConfigRef.changedDeferredKeys only classified seven top-level FleetConfig
keys (#323 fixed the profile side). Two more keys are read only off the
startup snapshot and were missing:
- primary: Fleetd.java:506/519/520 feed PrimaryRegistry and ReplyPushLoop
at construction; neither is rebuilt on reload.
- configReload: Fleetd.java:679-680 decide once at startup whether to
build a ConfigWatcher at all, and with what interval; the watcher that
would apply a later change is itself built once, so it is deferred
(not cold — no already-open resource goes inconsistent, a running
watcher just keeps its original settings).
health and coordinator are deliberately left unclassified: both are read
both off the startup snapshot AND live off the config supplier at a
second call site, so no single bucket is correct for either — see the
PR body for the options writeup and the coordinator.uriEnv exposure
question the issue asked to be answered.
Each fix is proven with a failing-first test in ConfigRefTest and a
revert-quote-restore mutation check (see PR body for the transcripts).
answer() holds sessionLocks while finishAsyncTask reads the volatile Task.turnId twice — once to
check it is non-null, once as the ConcurrentHashMap.remove key. ask()'s own timeout path mutates
the same field with no lock, via clearAsyncQuestion(turnId, true). volatile makes each read fresh
but not the pair atomic, so the field can go null between the two reads and remove(null, task)
throws NullPointerException on the lead's own answer() call, even though the reply already
completed on the line above.
Capture task.turnId into a local once and use that for both the check and the removal.
Added a package-private test seam (finishAsyncTaskRaceHook + forgetTurnForTest) so a test can force
the exact interleaving deterministically, by running the identical clearAsyncQuestion(turnId, true)
cleanup ask() uses, at the point between finishAsyncTask's former two reads. Both are inert (null)
in production.
ConfigRef.sameLaunchSettings' javadoc claimed it compares every component
the launcher reads at spawn. It missed ideProjectDir, ideOpenCommand and
autoCompactWindow, and changedDeferredKeys separately missed worktreeGroup
(baked into the same GitWorktrees as worktreeRoot, Fleetd.java:251). A
reload that changed only one of those keys reported "config reloaded" with
nothing deferred, and the running daemon kept the old value.
Fix the four instances, and add ConfigRefProfileCoverageTest: it enumerates
every FleetConfig.Profile record component by reflection, mutates each one
not in the new ConfigRef.LAUNCH_SETTINGS_EXCLUDED set on a base profile,
and asserts sameLaunchSettings actually notices — so a fifth missed field
fails the build by name instead of drifting silently. It also prints its
own denominator (26 components, 23 compared, 3 excluded) per the ticket's
requirement that a checker must be able to state what it checked.
Also add the `profile` field itself to the comparison (it was neither
compared nor excluded before this fix — the coverage test surfaced it).
Rewrote the sameLaunchSettings javadoc to describe what the coverage test
actually guarantees instead of repeating the unchecked claim.
SessionManager.releaseRemoved read hasUncommitted() once, while the worker
could still write, then used that stale boolean after launcher.stop() to
authorise `git worktree remove --force`. The same stale read also gated
trySnapshot, so a worker that wrote between the read and the stop lost its
work with neither a preserve nor a snapshot.
Add a second, best-effort hasUncommitted read immediately before the
removal, taken only on the path that is actually about to delete something
(never on a release that already decided to preserve, and never for
SHUTDOWN, which preserves unconditionally). If the tree is now dirty,
preserve it and attempt a fresh snapshot, since the original snapshot never
ran when the pre-stop read said clean. A failing re-check also preserves,
matching the existing CB-581 fail-safe rule.
AmqpReplyInbox.release() used held.remove(target) then iterated the old
map. A delivery landing on the consumer work-pool thread after the
remove (basicCancel does not flush one already handed to that pool) hit
deliverCallback's computeIfAbsent, found the key gone, and created a
brand-new map release() never looks at again — delivered-but-unacked
forever, never requeued, never redelivered (#298 only closed the
"already in held when release runs" case).
Fix: release() swaps in a RELEASED tombstone via held.compute(...)
instead of held.remove(...). ConcurrentHashMap serializes compute/
computeIfAbsent calls for the same key against each other, so whichever
of release() and a concurrent deliverCallback runs first is fully
visible to the other — no gap. deliverCallback checks for the
tombstone and nacks-with-requeue instead of recreating a map; peek/ack
treat it as empty; own() clears a stale tombstone so a target is never
poisoned if its id is ever reused (the issue's own text says id reuse
doesn't happen, but the tombstone would otherwise sit in `held` forever
either way).
New test AmqpReplyInboxReleaseRaceTest forces the actual interleaving
with a latch (blocks release() inside its nack loop, which is only
reachable after the tombstone swap, then fires a concurrent delivery)
rather than a sequential call — a sequential test would not have caught
this, since #298's own contract test forces settlement before release()
runs. Mutation-tested: reverting the fix makes this test fail with
"expected: <2> but was: <1>" (m1 never nacked); restored after
confirming that failure.
ConnectionIdentity.resolve() called pids.pidForLocalPort(remotePort),
which returns -1 both on a real failure and (silently, no log line)
when lsof just finds no matching process. terminalForPid(-1) then
matches no pane, so CallerResolver's loopback-trust fallback could not
tell that caller apart from a genuine primary and handed it
Principal.primary(...) — granting SPAWN, STOP, SEND and DRAIN to a
worker whose PID lookup failed. This is the escalation PaneLocator's
own javadoc already names; CB-161's ancestry walk only helps once a
candidate pid exists, and a failed lookup has none.
Fix: ConnectionIdentity.Caller gets a resolved() predicate (pid > 0),
centralised next to the -1 sentinel it tests for the same reason
isLoopback() is centralised (fleetd #305: two independent copies of
one rule already drifted once). CallerResolver's loopback-trust
fallback now requires c.resolved() before granting PRIMARY; an
unresolved caller gets Principal.anonymous() — the same already-tested
"authenticated as nothing" outcome used everywhere else in that
method, so the refusal is a clean, named, unsurprising result rather
than something that looks like a bug.
Also logs the previously-silent "lsof ran clean, found no match" case
in LsofPeerPidLookup at DEBUG, since that (not a slow lsof — the
waitFor result was already discarded) is the likelier real trigger.
loopbackTrustTreatsANonWorkerLoopbackCallerAsThePrimary is untouched
and still green: a real pid that owns no pane (the actual primary) is
still resolved() and still PRIMARY. Token mode is unaffected — it
never consults c.pid() at all.
Mutation-tested: reverting only the CallerResolver.java guard
reproduces the escalation exactly (aFailedPeerPidLookupIsRefusedNotPromotedToPrimary
fails with "expected: <ANONYMOUS> but was: <PRIMARY>").
FixedPlacementPolicy's class javadoc still opened with "This ignores caps
and reachability" after the previous commit added reachability as the
fourth carve-out that is explicitly NOT ignored — caught by a shape-check
survey run against this same file as part of #315's own request ("look in
placement/ ... for the same shape: a caller/comment that documents an
expectation ... where an implementation does not meet it"). Reworded the
opening sentence: fixed still ignores caps (maxLoad) by design, but
reachability is now a narrower, per-call retry exclusion, not an ignored
concern.
CompositePeerLauncher.spawn retries a failed candidate on the next one and
rebuilds PlacementContext "so the policy excludes this profile" (its own
comment), but FixedPlacementPolicy.select never read ctx.unreachable(). Under
the default `fixed` placement policy (used when `placement` is unset or set
to `fixed`), every retry re-picked the same dead default and a second,
healthy, configured profile was never tried. This also covers the wiring-bug
branch (a candidate profile with no owning adapter), which hit the exact same
symptom for the same reason.
Not live on this fleet: fleetd.yaml sets placement: weighted, which already
consults ctx.unreachable() via PlacementPolicyUtil.available(). This is live
only for a deployment that leaves placement unset or sets it to fixed.
Fix is in FixedPlacementPolicy: consult ctx.unreachable() in the same two
places it already consults quarantined/coolingOff (the default check and the
fallback walk over candidates()), and add a fourth reason to the "no
candidate remains" exception. Considered fixing this in
CompositePeerLauncher's retry loop instead (break when select() returns an
already-unreachable profile), but that only fails faster on the same dead
profile — it cannot make the loop advance to a different candidate, because
only the policy decides which candidate is next. The defect is that one
policy implementation does not honor the loop's stated contract, so the fix
belongs in that policy, matching how weighted/round-robin already behave.
Also fixed: the "no reachable worker profile" exception message said
"trying N candidate(s)" where N was unreachable.size(), a count of DISTINCT
profiles (a HashSet dedupes a profile added twice), under wording that reads
as a count of attempts. Reworded to "N distinct candidate(s)" so the count
matches what is measured and the profile list that follows it.
Tests: two new failover tests next to the three existing ones in
CompositePeerLauncherTest (which all use PlacementPolicies.weighted(), which
is why this had no coverage) — one pinned to PlacementPolicies.fixed() for
the unreachable-default case, one for the wiring-bug (no adapter) case.
Mutation-proofed: reverted FixedPlacementPolicy.java, both new tests failed
with the exact bug ("no reachable worker profile available after trying 1
distinct candidate(s): a" / "...c"), then restored the fix.
MessageService.reply()'s async-recovery path (askAnsweredAsyncTasks)
required a live Task.turnId, but ask()'s own TimeoutException handler
calls clearAsyncQuestion(turnId, true) — deliberately forgetting turnId
so hasAsyncQuestion() stops reporting the target BUSY. That made a
worker's eventual real fleet_reply, after an unanswered fleet_ask, fall
through to the inbox: fleet_poll{ticket} stayed PENDING forever and was
later force-failed with the false reason "session released before it
replied".
Fix: a new Task.askTimedOut marker is set (markAskTimedOut) right
before the turnId is forgotten, and askAnsweredAsyncTasks accepts it in
place of a live turnId. The marker never touches asyncTasksByTurn, so
the BUSY-release behaviour (invariant 1) is untouched. The existing
ambiguity guard (candidates.size() > 1 -> inbox, never guess) still
applies unchanged, but is now genuinely reachable rather than pure
defence in depth, since an ask timeout frees its target for a fresh,
independent delegation — the affected javadocs are updated to say so.
Tests: MessageServiceTest.aReplyAfterAnAskTimeoutStillCompletesTheAsyncTicket
(positive, mutation-proven) and
.twoAskTimedOutTicketsOnOneTargetFallBackToTheInboxRatherThanGuess
(negative/ambiguity). FleetMcpTest's
unansweredAsyncAskReturnsTheTicketToPending was renamed and its final
assertion updated — it had pinned the old (buggy) inbox-stranding
behaviour as expected.
The compare-and-release declines silently. This race is unobservable by
construction, so a reaper that quietly stops reaping is the hardest kind of
behaviour to diagnose later. One debug line names the pane and the likely
cause.
drainAll iterated a one-shot registry snapshot with nothing to refuse a new
fleet_spawn while the drain was still running (mcp.close() only runs 8 calls
after sessions.close() in the shutdown hook). A session registered in that
window was never visited by the drain loop: its pane kept running and its
worktree was never preserved, with the in-memory registry gone at exit.
Fix, both mechanisms as the issue asked for (neither alone is complete):
- SessionManager.acquire now checks a `draining` flag, flipped true at the
very start of drainAll before the registry snapshot is even taken, and
throws the new ShuttingDownException (invariant 3: fail loudly, say why).
FleetMcp.spawn and FleetApp.spawnMember surface it as a clean error/503
rather than an uncaught RuntimeException.
- The flag alone cannot close the whole race: a caller already past the
check can still be mid-launcher.spawn() (a real herdr round trip) when
drainAll snapshots the registry. drainAll now re-reads the registry once
its main pass finishes and drains whatever straggler landed there too,
bounded by the SAME whole-drain deadline (invariant 1: timeoutNanos stays
a budget for the whole drain, never extended for a straggler).
- ReleaseCause.SHUTDOWN still preserves worktrees for both the initial pass
and the sweep (invariant 2, unchanged release() path).
Tests (SessionManagerTest): a guard test proving acquire() throws once
drainAll has started, and a race test using a launcher double that blocks
the second spawn() and the first stop() call to force, deterministically,
the exact interleaving where a spawn passes the guard before drainAll flips
it and only registers after the initial snapshot — proving the post-loop
sweep catches it.
Shape check (SessionManager.java only, not fixed): reapIdle has the same
shape — a decision made from a roster() snapshot, then acted on via
release(s.paneId()) with no re-check of the session's current state.
Four latches gate delivery in Injector, and only awaitingCompletion had a way
out of a sustained unknown streak. CB-109 added that escape because a worker
stuck in a state herdr cannot classify never produces a working->idle
boundary. The same is true during post-turn housekeeping, but the escape was
never extended there.
awaitingPostTurnPickup and postTurnObserved are both released only on an
injectable sample, so a worker that goes unknown and stays there wedges: the
target is polled forever, every later message to it is blocked by the delivery
gate, and no onTurnFailed fires, so the session sits at DONE and looks healthy.
The counter did not even increment, since ++unknownSinceTurn sits inside the
awaitingCompletion short-circuit.
postTurnPending needs no escape; it is cleared on the line after the listener
call that sets it.
The escape does not set turnFailed. The delegated turn already completed and
its waiter already resolved — what is outstanding is the /clear. Failing the
turn would drive SessionManager.onFailed on a session that genuinely finished.
Not reachable in the live configuration: the path needs lifecycle.clearAfterTurn,
which fleetd.yaml does not set. It becomes reachable as soon as anyone turns
that supported knob on.
Fixes#306
ConnectionIdentity and CallerResolver each kept their own isLoopback. They
drifted: the identity resolver accepted only 127.0.0.1, the authorization
check accepted all of 127.0.0.0/8.
A caller from 127.0.0.2 therefore had its identity resolution skipped, so it
carried no terminal, and CallerResolver reads a missing terminal as "not a
worker" — which under loopback-trust, the default mode, is the primary. A
worker got spawn, stop, send and drain. The skip also happens before the PID
ancestry walk, so that defence is bypassed too.
Being strict in ConnectionIdentity was not the safe direction. That predicate
decides whether identity is resolved at all, and resolution is what demotes a
worker, so every address it excluded was one where a worker became the lead.
Measured, not assumed: on Linux the whole 127.0.0.0/8 is bound to lo, and
binding a source of 127.0.0.2 on the fleet host succeeds (curl rc=7, the
connect refused rather than the bind). On macOS the source bind fails (rc=45),
so this workstation was never exposed.
The shared predicate also accepts the IPv4-mapped IPv6 form, which neither
copy handled. That one failed in the safe direction: a primary on
::ffff:127.0.0.1 was refused as anonymous.
No transport-level test binds a real 127.0.0.2 source — it cannot run on
macOS. The reasoning is recorded on the issue.
Fixes#305
POST /members and DELETE /members/{paneId} were the two routes in FleetApp
with no catch (HerdrException). FleetApp has no Javalin exception mapper, so
the exception escaped as the default 500 with the body "Server Error" — no
herdr code, no herdr message. fleet_spawn and fleet_stop catch the same
exception and report a named error, so this was the same one-door-guarded
shape as #297.
Both now go through the existing herdrError mapper: 404 when herdr says the
target is gone, 502 otherwise. That is an answer the caller can act on.
stopMember matters more than spawnMember. SessionManager.release deregisters
the session, notifies the release listener and preserves a dirty worktree
before it calls launcher.stop, so a throw from that stop arrives after the
teardown the caller asked for has already happened. A bare 500 told the caller
to retry and carried nothing to explain what went wrong.
The two existing tests that asserted 500 now assert 502 and check the error
body. Neither was about the status code: one guards that a failed teardown is
not reported as a successful 204, the other that a failed spawn still closes
its tab. Both properties are unchanged.
Fixes#304
MessageService.reply now throws on blank content. FleetMcp.reply guarded only
against null, and its handler is a bare BiFunction with no try/catch, so a
whitespace-only fleet_reply left the handler as an uncaught
IllegalArgumentException instead of the clean tool error null already got.
fleet_send has always used isBlank here; reply now matches it.
The worker found that null/isBlank difference and reported it as a correction
to my ticket, which had quoted the guard wrongly. It was right: I grepped the
error string and assumed the condition matched its sibling.
REST read content with .path("content").asText(""), so a body missing the key
became an empty string that resolved the lead's waiter. The turn completed and
the lead saw a member that finished and reported nothing, indistinguishable
from one that genuinely said nothing. The guard went into MessageService.reply,
which both doors call, rather than being written a second time in FleetApp.
release() cancelled the consumer and dropped its local record of deliveries the
broker still held as outstanding. Cancelling a consumer does not requeue them:
they stay unacked on the still-open channel until it or the connection closes.
So a held-but-undrained reply became permanently unreachable — a worker's
report lost with no error and no log line. It now nacks with requeue, after
cancelling, so a later own() can still receive it.
The merged change shared the QuarantineSource and OutageSource instances
between fleet_profiles and GET /profiles, so the two doors read identical
facts. It then rendered those facts through a character-for-character copy of
the loop, in a different file. Shared inputs do not make duplicated computation
safe: a later edit to the row shape lands on one door and not the other, and
the two disagree about a live outage. That is what #284 was.
The ticket caused this. It said 'read from the same shared instances' and 'do
not change FleetMcp', and together those made copying the loop the only legal
move. Extracting FleetMcp.profilesView and calling it from both is what the
ticket should have asked for.
GET /agents and GET /members now map a herdr transport failure into the same
{error, detail} envelope every other handler in FleetApp uses, instead of
letting it escape to Javalin's default handling. GET /profiles now reports the
quarantined and coolingOff states, read from the same shared sources FleetMcp
reads. REST is the door a lead falls back to when its MCP mount drops, so it
was weakest exactly when it was load-bearing.
release(target) used to cancel the target's consumer and clear held's local
record for it. Cancelling a consumer does not requeue the broker's in-flight
deliveries — they stay unacked on the still-open channel until a real
connection drop. So a held-but-undrained reply became permanently
unreachable: never acked, never nacked, never requeued, invisible to peek.
Fix: cancel the consumer first (so it can no longer receive redeliveries),
then nack-with-requeue every held delivery for that target before dropping
the local record. Nacking before the cancel was tried first but a real
broker demonstrated a race: the still-active consumer immediately received
the requeued message back, racing held.remove and leaving peek non-empty.
Cancelling first avoids that. A failed requeue is logged at WARN and does
not abort release(), matching the best-effort teardown style #293 settled
for HerdrPeerLauncher.stop().
Extends AmqpReplyInboxContractTest.releaseCancelsConsumer... to assert the
held delivery is recoverable via a later own(), not just absent from peek.
Two REST-only visibility gaps, both against the same shared instances FleetMcp
reads (BackendQuarantine/BackendOutagePolicy), never recomputed:
- GET /agents and GET /members let a HerdrException escape uncaught, outside
the {error, detail} envelope every other failure path in FleetApp uses.
Both now route through the existing herdrError() helper, matching healthz/
sessionStatus. GET /members is the endpoint's own comment names as the
out-of-band path a lead falls back to when its MCP mount drops.
- GET /profiles omitted the two outage states fleet_profiles already reports:
quarantined (CB-578 stage B) and coolingOff (fleetd #201 Unit 5). FleetApp
now takes the SAME FleetMcp.QuarantineSource/OutageSource instances Fleetd
wires into FleetMcp (extracted to local vars in Fleetd.java so both doors
share one object, not two independently-built copies of the same rule).
FleetMcp itself is unchanged. Item 3 of the ticket (a capacity block on
GET /members) is explicitly out of scope and was not added.
The javadoc said 'for each session that is BUSY, poll up to timeoutNanos',
which reads as a per-session grace period. The deadline is taken once, before
the loop, so the first BUSY session can spend all of it. That is deliberate and
is the safer of the two designs: the drain is one phase of a shutdown sequence
that must finish inside launchd's exit window, and a per-session grace would
overrun it and get the daemon SIGKILLed part-way through, leaving the sessions
not yet reached with no clean release, no preserved-worktree log and no
snapshot. Found by a read-only hunt that read the code correctly and drew the
opposite conclusion from the wording.
Two exits created a pane and left it running. The readiness gate propagated an
unrelated herdr error without teardown, and spawnAsPane never closed the pane it
split when the peer failed to start. Neither could be cleaned up by the caller:
SessionManager.acquire never learns the pane id, because spawn throws before it
returns one. It removed the worktree anyway, so the leak was a live backend with
a deleted cwd, invisible to fleet_list and holding a seat nothing decremented.
No behaviour change today. HerdrCodec wraps every encode/decode failure
and UnixSocketHerdrClient wraps every IOException, so HerdrException is
all closeTab can currently throw.
But releaseZdotdir five lines below catches RuntimeException, and the
whole point of this fix is that nothing here may mask the cleanups
below. Guarding against the expected exception type and staying bare
against any other is the same asymmetry the ticket exists to remove,
one level down. This stops a later change inside
WorkspaceControl.closeTab reopening it.
The pane is already closed by the time spaces.closeTab runs, so a failing
tab.close is cosmetic workspace tidying, not a real teardown failure. Left
bare, it propagated out of stop() and masked releaseZdotdir (ZDOTDIR leak)
and, worse, SessionManager.release()'s worktree removal (no self-heal,
no retry — the registry entry is already gone by then).
Wrap it in a try/catch that logs a WARN naming the tab id, matching the
"must not mask a real teardown failure above" comment already on
releaseZdotdir. isAlreadyGone is untouched — this continues past *any*
tab.close failure, not just *_not_found, since the failure is cosmetic
regardless of its cause.
Adds FakeHerdr#tabCloseFailsWith/tabCloseFailsForTab (the tab.close
counterpart to #290's paneCloseFailsForPane) plus two tests: one proving
releaseZdotdir still runs (the generated ZDOTDIR is deleted) and one
proving SessionManager.release() still removes the worktree, both with a
non-not_found tab.close failure.
The delayed re-check reads `states` from its own scheduled task, while
`tick` writes and prunes it. Both run on the single-threaded scheduler
Fleetd passes in today, so they are serialised — but nothing in the
class enforces that, and an unsynchronised HashMap read racing a resize
can spin a CPU forever rather than fail visibly.
`priors` and `orphanStreaks` stay plain maps: `tick` is still their only
toucher. The comment says which is which, so the next person does not
have to re-derive it.
FleetHealthMonitor's fire-once-per-transition rule (CB-580) means a target
that is genuinely mid-fleet_ask when health first classifies it GONE is
correctly skipped (sweepAsking=false). But nothing re-fires abandon() once
that ask lapses on its own 55-115s later: FleetHealth.decide keeps reporting
GONE every tick, and reportTransition's previous==next guard never lets the
sweep run again. The ticket then sat PENDING forever, the same destination
#275 fixed for an explicit teardown, reached here by a health guess instead.
SessionManager.reapIdle only reaps READY/DONE sessions (SessionManager.java:844),
and a session mid-turn (including mid-ask) stays BUSY the whole time
(onDelivered sets BUSY, nothing clears it until the turn completes) — so
SessionReaper never releases such a session and onRelease's sweepAsking=true
path is never reached.
Fix: schedule one bounded, delayed re-check per terminal transition (not a
per-tick retry — that shape was rejected by CB-580). It fires failTerminalTarget
again after a delay that exceeds the worst-case ask-lapse window, and only if
the target is still classified in the same terminal state at that time, so a
recovered or since-released target is never reached into. sweepAsking stays
false throughout, so a ticket whose ask has not yet lapsed is still never
touched — same invariant abandonDoesNotFailAnAsyncTicketWaitingForAnAnswer pins.
Proven with a mutation: neutering recheckTerminalTarget's body made
delayedRecheckSweepsATicketWhoseAskLapsedAfterGoneWasFirstObserved fail with
"expected: <FAILED> but was: <PENDING>", all 20 other FleetHealthMonitorTest
cases still green; restored and reran clean (1300 tests, 0 failures).
Dai Ha