T1: the seat settle applies a delayed nak with the bus's own delay (ADR 0664 §1, issue 1748)

Claude-Session: https://claude.ai/code/session_01JG73KEq4zoDfM9WtYpcQgZ

node-tools/internal/bus/seat_pull.go

@@ -147,11 +147,27 @@ const (
 	SettleNak      = "nak"      // handed back, to be delivered again at once
 	SettleTerm     = "term"     // dropped
 	SettleProgress = "progress" // still being worked: its acknowledgement wait starts again
+	// SettleNakAfter hands the message back to be delivered again after a delay: the bus's own redelivery, so no part
+	// keeps a timer for a step given again (novox/hq ADR 0664 §1; issue 1748). SeatSettleAfter gives it.
+	SettleNakAfter = "nak-after"
 )
 
 // SeatSettle gives the message module pulled under id its fate. A message pulled for another module, or settled
 // already, is refused.
 func (c *Conn) SeatSettle(module, id, fate string) error {
+	return c.settle(module, id, fate, 0)
+}
+
+// SeatSettleAfter hands the message module pulled under id back to be delivered again after delay (SettleNakAfter),
+// counting one more delivery. A delay of 0 or below is refused and settles nothing.
+func (c *Conn) SeatSettleAfter(module, id string, delay time.Duration) error {
+	if delay <= 0 {
+		return fmt.Errorf("a message given again after a delay needs a delay above 0, not %s", delay)
+	}
+	return c.settle(module, id, SettleNakAfter, delay)
+}
+
+func (c *Conn) settle(module, id, fate string, delay time.Duration) error {
 	seatPulls.mu.Lock()
 	p, ok := seatPulls.held[id]
 	if ok && p.module != module {
@@ -173,9 +189,11 @@ func (c *Conn) SeatSettle(module, id, fate string) error {
 		return p.msg.Term()
 	case SettleProgress:
 		return p.msg.InProgress()
+	case SettleNakAfter:
+		return p.msg.NakWithDelay(delay)
 	}
 	seatPulls.mu.Lock()
 	seatPulls.held[id] = p // an unknown fate settles nothing
 	seatPulls.mu.Unlock()
-	return fmt.Errorf("a pulled message's fate is ack, nak, term or progress, not %q", fate)
+	return fmt.Errorf("a pulled message's fate is ack, nak, nak-after, term or progress, not %q", fate)
 }

node-tools/internal/bus/seat_pull_test.go

@@ -58,6 +58,21 @@ func TestAHolderPullsOneMessageWhenItHasRoom(t *testing.T) {
 	if err != nil || again == nil || string(again.Body) != `{"id":"a2"}` || again.Delivered != 2 {
 		t.Fatalf("the message handed back = %+v, %v", again, err)
 	}
+	// Issue 1748: a message settled with a delay is not given again at once, is after it, one delivery higher; a delay
+	// of 0 settles nothing.
+	if err := conn.SeatSettleAfter("messenger", again.ID, 0); err == nil {
+		t.Error("a delay of 0 was accepted")
+	}
+	if err := conn.SeatSettleAfter("messenger", again.ID, 300*time.Millisecond); err != nil {
+		t.Fatal(err)
+	}
+	if early, err := conn.SeatPull("messenger", "SEAT_OPERATOR_CHANNEL_worker", 0); err != nil || early != nil {
+		t.Fatalf("a message given again after a delay came at once: %+v, %v", early, err)
+	}
+	late, err := conn.SeatPull("messenger", "SEAT_OPERATOR_CHANNEL_worker", 2*time.Second)
+	if err != nil || late == nil || late.Delivered != 3 {
+		t.Fatalf("the message given again after its delay = %+v, %v", late, err)
+	}
 	if _, err := conn.SeatPull("telegram", "SEAT_OPERATOR_CHANNEL_worker", 0); err == nil || !strings.Contains(err.Error(), "membership lists") {
 		t.Errorf("a channel pulled the router's work: %v", err)
 	}