D3: the teller keeps an assigner ask whose publish failed waiting, and asks it at the next end and at its start (issue 1966, ADR 0668 §1)

A failed publish deleted the kept record for "the next writing of the key", which nothing made.
The ask now joins the teller's wait for room, kept on the bus, which asks again at the next end
and at the start. The gate's asks are left as they are (ADR 0666 §6 replaces them).

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

modules/mesh-delivery-teller/cmd/mesh-delivery-teller/assignerasks.go

@@ -191,10 +191,11 @@ func (t *Teller) raiseAssignerAsk(key string) {
 		return
 	}
 	if err := t.Asker.Ask(a.Ask); err != nil {
-		t.logf("%s: the ask %s was not asked: %v", key, id, err)
-		if kept, _, _ := t.keptOf(id); open(kept) {
-			_ = t.Store.Delete(keptKey(id)) // kept but not published: forgotten, so the next writing of the key asks it
-		}
+		// Kept but not published (a transport fault, the router restarting): nothing writes the key again, so the ask is not
+		// forgotten but waits, kept on the bus, to be asked again at the next end and at the teller's start (issue 1966,
+		// ADR 0668 §1). Before, the record was deleted for "the next writing of the key", which never came.
+		t.logf("%s: the ask %s was not asked: %v; it waits to be asked again at the next end and at the start", key, id, err)
+		t.unheard(id)
 		return
 	}
 	t.assignerAsked(id)

modules/mesh-delivery-teller/cmd/mesh-delivery-teller/assignerasks_test.go

@@ -1,6 +1,7 @@
 package main
 
 import (
+	"errors"
 	"slices"
 
 	"encoding/json"
@@ -34,6 +35,28 @@ func TestAnAssignerAskIsRaisedOnTheOperatorChannelOnce(t *testing.T) {
 	if got.ID != ask.ID || occ.Digest(got) != occ.Digest(ask) {
 		t.Errorf("the router's ask %+v differs from the assigner's", got)
 	}
+	// Issue 1966, ADR 0668 §1: a publish that fails (the router restarting) is not forgotten: the ask waits, kept, and is
+	// asked at the teller's next start (or the next end), though nothing writes the assigner's key again.
+	b = newBed(t)
+	assigner, _ = withView(b)
+	assigner[key] = value
+	publish, failed := b.client.Publish, false
+	b.client.Publish = func(subject string, body any, id string) error {
+		if subject == oc.AcceptSubjectAsk(tellerModule) && !failed {
+			failed = true
+			return errors.New("nats: no responders available for request")
+		}
+		return publish(subject, body, id)
+	}
+	b.t.Publish = b.client.Publish
+	b.t.OnAssignerAsk(key)
+	if asked := b.askedOf(oc.AcceptSubjectAsk(tellerModule)); !failed || len(asked) != 0 {
+		t.Fatalf("published %d asks through a failing publish", len(asked))
+	}
+	b.t.OnCurrent()
+	if asked := b.askedOf(oc.AcceptSubjectAsk(tellerModule)); len(asked) != 1 {
+		t.Errorf("after a failed publish and a start, published %d asks, want one; log:\n%s", len(asked), b.logs.String())
+	}
 }
 
 // 1906/H1: without the view's bucket the assigner's asks are still raised.