node-tools: only a call pattern names a caller, and a fall-back for want of a responder is said (hq issue 365, review)

callerOn reads a caller only under the call kind, so a tool subscription ending
in a wildcard never yields one. A caller-named call that reached nobody is said
once per subject before it is asked on the old subject, so a runtime or grant
that drifted behind is seen rather than a quiet unproven. The caller tests wait
for their bundle's exit, which reads the launcher's restart pauses another test
sets.

node-tools/internal/bus/caller.go

@@ -91,7 +91,11 @@ func calledPattern(subject string) string {
 // callerOn is the bus user a call names, from the subject it arrived on: its last token, under a pattern
 // calledPattern made. "" — said by the module as Unproven — for a call on the subject that names no caller.
 func callerOn(pattern, subject string) string {
-	if !strings.HasSuffix(pattern, ".*") {
+	// Only the `call` kind names a caller: a `tool` pattern ending in a wildcard (a node seat's verb on any
+	// machine) is never read as one.
+	parts := strings.SplitN(pattern, ".", 5)
+	if len(parts) != 5 || parts[0] != "mesh" || (parts[1] != "mod" && parts[1] != "seat") || parts[3] != CallKind ||
+		!strings.HasSuffix(pattern, ".*") {
 		return ""
 	}
 	dot := strings.LastIndex(subject, ".")
@@ -107,9 +111,11 @@ type CalledHandler func(caller string, body json.RawMessage) (any, error)
 // callers is what a connection keeps of its caller-named calls: those in flight, by subject, so a refused
 // publish ends its call at once instead of after RequestTimeout.
 type callers struct {
-	mu      sync.Mutex
-	next    uint64
-	pending map[string]map[uint64]context.CancelCauseFunc
+	mu sync.Mutex
+	// fellBack are the caller-named subjects already said to have reached nobody, so each is said once.
+	fellBack map[string]bool
+	next     uint64
+	pending  map[string]map[uint64]context.CancelCauseFunc
 }
 
 // errCallRefused is the bus refusing a caller-named publish: this user is not granted it yet (the controller's
@@ -176,6 +182,7 @@ func (c *Conn) askCalled(subject string, data []byte) (answered Answered, handin
 		case errors.Is(context.Cause(ctx), errCallRefused):
 			return Answered{}, false, true, nil
 		case errors.Is(err, nats.ErrNoResponders):
+			c.saidFallBack(subject)
 			return Answered{}, false, true, nil
 		case errors.Is(err, context.DeadlineExceeded) || errors.Is(err, nats.ErrTimeout):
 			return Answered{}, false, false, errors.New("timeout")
@@ -185,3 +192,21 @@ func (c *Conn) askCalled(subject string, data []byte) (answered Answered, handin
 	answered, handingOver, err = c.answerOf(subject, msg.Data)
 	return answered, handingOver, false, err
 }
+
+// saidFallBack says, once per subject, that a caller-named call reached nobody and is asked on the subject that
+// names no caller: a runtime or holder not yet serving it, or a grant that drifted, is seen in the log rather
+// than read later as a quiet "unproven" (novox/hq issue 365; expected for the controller's seat until hq issue
+// 464).
+func (c *Conn) saidFallBack(subject string) {
+	c.calls.mu.Lock()
+	if c.calls.fellBack == nil {
+		c.calls.fellBack = map[string]bool{}
+	}
+	first := !c.calls.fellBack[subject]
+	c.calls.fellBack[subject] = true
+	c.calls.mu.Unlock()
+	if first {
+		c.Logf("[mesh-tools] nothing answers the caller-named %s; asked on the subject that names no caller, where "+
+			"the module is told no caller (said once per subject; novox/hq issue 365)", subject)
+	}
+}