ax(node): rename receiver d to deduplicator on MessageDeduplicator

Single-letter receiver `d` violates AX Principle 1 (predictable names
over short names). RFC-CORE-008 permits single-letter receivers only for
`i` (range loops), `_` (discards), `t` (tests), and `c` (*core.Core).

Co-Authored-By: Charon <charon@lethean.io>

pkg/node/transport.go

@@ -74,28 +74,28 @@ func NewMessageDeduplicator(ttl time.Duration) *MessageDeduplicator {
 }
 
 // if dedup.IsDuplicate(msg.ID) { continue } // drop already-processed message
-func (d *MessageDeduplicator) IsDuplicate(msgID string) bool {
-	d.mutex.RLock()
-	_, exists := d.seen[msgID]
-	d.mutex.RUnlock()
+func (deduplicator *MessageDeduplicator) IsDuplicate(msgID string) bool {
+	deduplicator.mutex.RLock()
+	_, exists := deduplicator.seen[msgID]
+	deduplicator.mutex.RUnlock()
 	return exists
 }
 
 // dedup.Mark(msg.ID) // call after IsDuplicate returns false
-func (d *MessageDeduplicator) Mark(msgID string) {
-	d.mutex.Lock()
-	d.seen[msgID] = time.Now()
-	d.mutex.Unlock()
+func (deduplicator *MessageDeduplicator) Mark(msgID string) {
+	deduplicator.mutex.Lock()
+	deduplicator.seen[msgID] = time.Now()
+	deduplicator.mutex.Unlock()
 }
 
 // go dedup.Cleanup() // call periodically; entries older than ttl are dropped
-func (d *MessageDeduplicator) Cleanup() {
-	d.mutex.Lock()
-	defer d.mutex.Unlock()
+func (deduplicator *MessageDeduplicator) Cleanup() {
+	deduplicator.mutex.Lock()
+	defer deduplicator.mutex.Unlock()
 	now := time.Now()
-	for id, seen := range d.seen {
-		if now.Sub(seen) > d.ttl {
-			delete(d.seen, id)
+	for id, seen := range deduplicator.seen {
+		if now.Sub(seen) > deduplicator.ttl {
+			delete(deduplicator.seen, id)
 		}
 	}
 }