fix p2p topic canonicalization and stale subscriptions

server/topic.go

@@ -262,8 +262,8 @@ func (t *Topic) prepareBroadcastableMessage(msg *ServerComMessage, uid types.Uid
 	}
 
 	if (t.cat == types.TopicCatP2P && !uid.IsZero()) || (t.cat == types.TopicCatGrp && t.isChan) {
-		// For p2p topics topic name is dependent on receiver.
-		// Channel topics may be presented as grpXXX or chnXXX.
+		// P2P topics are exposed by their canonical p2p... name. Channel topics
+		// may be presented as grpXXX or chnXXX.
 		var topicName string
 		if isChanSub {
 			topicName = types.GrpToChn(t.xoriginal)
@@ -2867,14 +2867,15 @@ func (t *Topic) replyGetSub(sess *Session, asUid types.Uid, authLevel auth.Level
 				banned = true
 			}
 
-			// Reporting user's subscriptions to other topics. P2P topic name is the
-			// UID of the other user.
+			// Reporting user's subscriptions to other topics. P2P topic names are
+			// reported by their canonical p2p... names; usr... remains accepted as
+			// an input alias only.
 			with := sub.GetWith()
 			canViewLastSeen := true
 			if with != "" {
-				mts.Topic = with
+				mts.Topic = sub.Topic
 				canViewLastSeen = imCanViewLastSeen(t.tenantID, asUid, types.ParseUserId(with))
-				mts.Online = t.perSubs[with].online && !deleted && presencer
+				mts.Online = t.perSubs[sub.Topic].online && !deleted && presencer
 				if !deleted && presencer {
 					mts.Online = redisUserOnline(t.tenantID, types.ParseUserId(with), mts.Online)
 				}
@@ -4130,8 +4131,8 @@ func (t *Topic) isDeleted() bool {
 // Get topic name suitable for the given client
 func (t *Topic) original(uid types.Uid) string {
 	if t.cat == types.TopicCatP2P {
-		if pud, ok := t.perUser[uid]; ok {
-			return pud.topicName
+		if _, ok := t.perUser[uid]; ok {
+			return t.name
 		}
 		panic("Invalid P2P topic")
 	}
@@ -4350,7 +4351,6 @@ func genTopicName() string {
 }
 
 // Convert expanded (routable) topic name into name suitable for sending to the user.
-// For example p2pAbCDef123 -> usrAbCDef
 func topicNameForUser(name string, uid types.Uid, isChan bool) string {
 	switch topicCat(name) {
 	case types.TopicCatMe:
@@ -4358,8 +4358,7 @@ func topicNameForUser(name string, uid types.Uid, isChan bool) string {
 	case types.TopicCatFnd:
 		return "fnd"
 	case types.TopicCatP2P:
-		topic, _ := types.P2PNameForUser(uid, name)
-		return topic
+		return name
 	case types.TopicCatGrp:
 		if isChan {
 			return types.GrpToChn(name)