cmd/mesh-host/seatlist.go

@@ -126,12 +126,18 @@ func (w findingsOfTheNode) Put(f views.Finding) error {
 	return w.session.PutFinding(key, raw)
 }
 
+// keyOf is the finding's key in the state; a read or a clear needs no more of the finding than Kind and ID.
+func (w findingsOfTheNode) keyOf(f views.Finding) string {
+	return conditions.Key(conditions.ScopeMachine, f.ID, f.Kind)
+}
+
 func (w findingsOfTheNode) Delete(f views.Finding) error {
-	key, _, err := w.encode(f)
-	if err != nil {
-		return err
-	}
-	return w.session.DeleteFinding(key)
+	return w.session.DeleteFinding(w.keyOf(f))
+}
+
+// Has says whether the finding stands in the node's state `findings` now.
+func (w findingsOfTheNode) Has(f views.Finding) (bool, error) {
+	return w.session.HasFinding(w.keyOf(f))
 }
 
 // startSeatList starts this run's reader: its bootstrapped seats are given to catalogue at once, and every change of what

internal/link/findings.go

@@ -42,6 +42,21 @@ func (q *Session) PutFinding(key string, value []byte) error {
 	return err
 }
 
+// HasFinding says whether one finding of this engine stands in its state now.
+func (q *Session) HasFinding(key string) (bool, error) {
+	kv, err := q.findings()
+	if err != nil {
+		return false, err
+	}
+	if _, err = kv.Get(key); err != nil {
+		if errors.Is(err, nats.ErrKeyNotFound) {
+			return false, nil
+		}
+		return false, err
+	}
+	return true, nil
+}
+
 // DeleteFinding clears one finding of this engine over the link open now; a finding already gone is cleared.
 func (q *Session) DeleteFinding(key string) error {
 	kv, err := q.findings()

internal/nodegrant/testdata/node.json

@@ -13,6 +13,7 @@
     "$JS.API.CONSUMER.CREATE.KV_mesh-delivery-indexer_verdicts.>",
     "$JS.API.CONSUMER.CREATE.KV_mesh-host_acts.*.$KV.mesh-host_acts.NODE.>",
     "$JS.API.CONSUMER.CREATE.KV_mesh-host_data.*.$KV.mesh-host_data.NODE.>",
+    "$JS.API.CONSUMER.CREATE.KV_mesh-host_findings.*.$KV.mesh-host_findings.machine.NODE.>",
     "$JS.API.CONSUMER.CREATE.KV_mesh-host_health.*.$KV.mesh-host_health.NODE",
     "$JS.API.CONSUMER.CREATE.KV_mesh-host_packages.*.$KV.mesh-host_packages.NODE",
     "$JS.API.CONSUMER.CREATE.KV_mesh-provisioner_provisions.*.$KV.mesh-provisioner_provisions.NODE.>",
@@ -31,6 +32,7 @@
     "$JS.API.CONSUMER.DELETE.KV_mesh-delivery-indexer_verdicts.>",
     "$JS.API.CONSUMER.DELETE.KV_mesh-host_acts.>",
     "$JS.API.CONSUMER.DELETE.KV_mesh-host_data.>",
+    "$JS.API.CONSUMER.DELETE.KV_mesh-host_findings.>",
     "$JS.API.CONSUMER.DELETE.KV_mesh-host_health.>",
     "$JS.API.CONSUMER.DELETE.KV_mesh-host_packages.>",
     "$JS.API.CONSUMER.DELETE.KV_mesh-provisioner_provisions.>",
@@ -49,6 +51,7 @@
     "$JS.API.DIRECT.GET.KV_mesh-delivery-indexer_verdicts.>",
     "$JS.API.DIRECT.GET.KV_mesh-host_acts.$KV.mesh-host_acts.NODE.>",
     "$JS.API.DIRECT.GET.KV_mesh-host_data.$KV.mesh-host_data.NODE.>",
+    "$JS.API.DIRECT.GET.KV_mesh-host_findings.$KV.mesh-host_findings.machine.NODE.>",
     "$JS.API.DIRECT.GET.KV_mesh-host_health.$KV.mesh-host_health.NODE",
     "$JS.API.DIRECT.GET.KV_mesh-host_packages.$KV.mesh-host_packages.NODE",
     "$JS.API.DIRECT.GET.KV_mesh-provisioner_provisions.$KV.mesh-provisioner_provisions.NODE.>",
@@ -84,6 +87,7 @@
     "$JS.FC.KV_mesh-delivery-indexer_verdicts.>",
     "$JS.FC.KV_mesh-host_acts.>",
     "$JS.FC.KV_mesh-host_data.>",
+    "$JS.FC.KV_mesh-host_findings.>",
     "$JS.FC.KV_mesh-host_health.>",
     "$JS.FC.KV_mesh-host_packages.>",
     "$JS.FC.KV_mesh-provisioner_provisions.>",
@@ -92,7 +96,7 @@
     "$KV.composed-NODE.>",
     "$KV.mesh-host_acts.NODE.>",
     "$KV.mesh-host_data.NODE.>",
-    "$KV.mesh-host_findings.>",
+    "$KV.mesh-host_findings.machine.NODE.>",
     "$KV.mesh-host_health.NODE",
     "$KV.mesh-host_packages.NODE",
     "$KV.node-engine_have.NODE.>",

internal/seatwait/seatwait.go

@@ -36,20 +36,32 @@ type Clock interface {
 	AfterFunc(d time.Duration, f func()) Timer
 }
 
+// Findings is the node's own state `findings`: the writer, and the read of whether a finding stands there. The bus state
+// is the one truth of whether the finding exists (ADR 0636 §1, issue 1966): the Waiter keeps no copy, so a new process
+// of the node-engine clears what an earlier one wrote.
+type Findings interface {
+	views.FindingWriter
+	Has(f views.Finding) (bool, error)
+}
+
 // Waiter writes and clears the node's finding.
 type Waiter struct {
 	Node     string
 	Observer string
 	Reader   Reader
-	Findings views.FindingWriter
+	Findings Findings
 	Clock    Clock
 	// Say tells the node's journal; nil says nothing.
 	Say func(string)
 
-	mu      sync.Mutex
-	timer   Timer
-	since   time.Time
-	written *views.Finding
+	mu    sync.Mutex
+	timer Timer
+	since time.Time
+}
+
+// key is the finding this node's Waiter writes: Kind and ID name it, the rest is its text.
+func (w *Waiter) key() views.Finding {
+	return views.Finding{Observer: w.Observer, Kind: Kind, ID: w.Node}
 }
 
 func waiting(st seatlist.Status) bool { return !st.Heard || len(st.Waiting) > 0 }
@@ -66,18 +78,24 @@ func (w *Waiter) Changed() {
 			w.timer = nil
 		}
 		w.since = time.Time{}
-		if w.written != nil {
-			if err := w.Findings.Delete(*w.written); err != nil {
+		stands, err := w.Findings.Has(w.key())
+		if err != nil {
+			w.say(fmt.Sprintf("the node's finding that its seat list is unread cannot be read: %v", err))
+			return
+		}
+		if stands {
+			if err := w.Findings.Delete(w.key()); err != nil {
 				w.say(fmt.Sprintf("the node's finding that its seat list is unread cannot be cleared: %v", err))
-				return
 			}
-			w.written = nil
 		}
 		return
 	}
-	if w.timer != nil || w.written != nil {
+	if w.timer != nil {
 		return
 	}
+	if stands, err := w.Findings.Has(w.key()); err == nil && stands {
+		return // an earlier process wrote it and the list is still unread: it stands until the first full read
+	}
 	w.since = w.Clock.Now()
 	w.timer = w.Clock.AfterFunc(Bound, w.expired)
 }
@@ -86,7 +104,11 @@ func (w *Waiter) Changed() {
 func (w *Waiter) Waiting() (bool, time.Time) {
 	w.mu.Lock()
 	defer w.mu.Unlock()
-	return w.timer != nil || w.written != nil, w.since
+	if w.timer != nil {
+		return true, w.since
+	}
+	stands, err := w.Findings.Has(w.key())
+	return err == nil && stands, w.since
 }
 
 func (w *Waiter) expired() {
@@ -98,6 +120,9 @@ func (w *Waiter) expired() {
 		w.since = time.Time{}
 		return
 	}
+	if stands, err := w.Findings.Has(w.key()); err == nil && stands {
+		return
+	}
 	f := views.Finding{Observer: w.Observer, Kind: Kind, ID: w.Node,
 		Summary:     fmt.Sprintf("%s has read no complete seat list since %s: %s", w.Node, w.since.UTC().Format(time.RFC3339), st.Health()),
 		Headline:    fmt.Sprintf("%s waits for the seat list", w.Node),
@@ -107,7 +132,6 @@ func (w *Waiter) expired() {
 		w.say(fmt.Sprintf("the node's finding that its seat list is unread cannot be written: %v", err))
 		return
 	}
-	w.written = &f
 	w.say(f.Summary)
 }
 

internal/seatwait/seatwait_test.go

@@ -48,16 +48,24 @@ func (c *fakeClock) advance(d time.Duration) {
 type fakeFindings struct {
 	put, deleted []views.Finding
 	err          error
+	standing     bool // the bus state holds the finding, written by this process or an earlier one
 }
 
+func (f *fakeFindings) Has(views.Finding) (bool, error) { return f.standing, nil }
+
 func (f *fakeFindings) Put(x views.Finding) error {
 	if f.err != nil {
 		return f.err
 	}
 	f.put = append(f.put, x)
+	f.standing = true
+	return nil
+}
+func (f *fakeFindings) Delete(x views.Finding) error {
+	f.deleted = append(f.deleted, x)
+	f.standing = false
 	return nil
 }
-func (f *fakeFindings) Delete(x views.Finding) error { f.deleted = append(f.deleted, x); return nil }
 
 // ADR 0636 §1: a reader that waited five minutes makes the node write one finding, which the first full read clears.
 func caseTheNodeWritesOneFindingAfterFiveMinutesAndClearsItAtTheFirstFullRead(t *testing.T) {
@@ -137,12 +145,35 @@ func caseAFindingThatCannotBeWrittenIsSaidAndTriedAgain(t *testing.T) {
 	}
 }
 
+// A finding an earlier process wrote stands in the bus state: the new process clears it at its first full read with no
+// write first, and while the list stays unread it neither starts a bound nor writes it again (ADR 0636 §1, issue 1966).
+func caseAFindingOfAnEarlierProcessIsClearedAtTheFirstFullRead(t *testing.T) {
+	reader := &fakeReader{st: seatlist.Status{Heard: false}}
+	clock := &fakeClock{now: time.Date(2026, 11, 11, 12, 0, 0, 0, time.UTC)}
+	findings := &fakeFindings{standing: true}
+	w := &Waiter{Node: "ace", Observer: "node-engine", Reader: reader, Findings: findings, Clock: clock}
+	w.Changed()
+	clock.advance(Bound)
+	if len(findings.put) != 0 || len(clock.timers) != 0 {
+		t.Fatalf("a standing finding was written again (%+v) or a bound started (%d)", findings.put, len(clock.timers))
+	}
+	if on, _ := w.Waiting(); !on {
+		t.Error("the waiter does not say the finding stands")
+	}
+	reader.st = seatlist.Status{Heard: true}
+	w.Changed()
+	if len(findings.deleted) != 1 || findings.deleted[0].ID != "ace" || len(findings.put) != 0 {
+		t.Fatalf("the first full read left the earlier process's finding: deleted %+v, put %+v", findings.deleted, findings.put)
+	}
+}
+
 // ADR 0636 §1, the node's finding of a seat list unread.
 func TestTheSeatListWait(t *testing.T) {
 	for name, run := range map[string]func(*testing.T){
-		"five minutes write one finding and the first full read clears it": caseTheNodeWritesOneFindingAfterFiveMinutesAndClearsItAtTheFirstFullRead,
-		"a read within the bound writes nothing":                           caseAReadWithinTheBoundWritesNothing,
-		"a finding that cannot be written is said and tried again":         caseAFindingThatCannotBeWrittenIsSaidAndTriedAgain,
+		"five minutes write one finding and the first full read clears it":  caseTheNodeWritesOneFindingAfterFiveMinutesAndClearsItAtTheFirstFullRead,
+		"a read within the bound writes nothing":                            caseAReadWithinTheBoundWritesNothing,
+		"a finding that cannot be written is said and tried again":          caseAFindingThatCannotBeWrittenIsSaidAndTriedAgain,
+		"a finding of an earlier process is cleared at the first full read": caseAFindingOfAnEarlierProcessIsClearedAtTheFirstFullRead,
 	} {
 		t.Run(name, run)
 	}