fix9b2-6: the publish queue sends in the order it queued, whatever the clock says between two versions

Builds: design 47 G §588 (newest first)

modules/mesh-delivery-builder/internal/versions/republish.go

@@ -118,6 +118,22 @@ type Republisher struct {
 	mu   sync.Mutex
 	runs map[string]map[string][]string // node -> holder module -> the registry seats it claims
 	busy map[string]bool
+	// lastQueued is the newest time a version was queued at: a clock that has not moved between two versions (a coarse clock,
+	// or a fixed one) must not make the queue's order the order of its keys, so each is queued after the last.
+	lastQueued time.Time
+}
+
+// queuedAt is the time a version is queued at: now, or a nanosecond after the last one queued when now is not after it, so the
+// order the versions were queued in (newest reservation first) is the order they are sent in.
+func (r *Republisher) queuedAt() time.Time {
+	r.mu.Lock()
+	defer r.mu.Unlock()
+	at := r.now()
+	if !at.After(r.lastQueued) {
+		at = r.lastQueued.Add(time.Nanosecond)
+	}
+	r.lastQueued = at
+	return at
 }
 
 func (r *Republisher) now() time.Time {
@@ -349,7 +365,7 @@ func (r *Republisher) enqueue(ctx context.Context, v ReservedVersion, holder str
 	} else if found {
 		return false, nil
 	}
-	raw, _ := json.Marshal(QueuedPublish{V: 1, Holder: holder, Module: v.Module, Version: v.Version, Artifacts: arts, Queued: r.now()})
+	raw, _ := json.Marshal(QueuedPublish{V: 1, Holder: holder, Module: v.Module, Version: v.Version, Artifacts: arts, Queued: r.queuedAt()})
 	used, err := r.Queue.Bytes(ctx)
 	if err != nil {
 		return false, fmt.Errorf("the size of %s cannot be read: %w", PublishQueueBucket, err)