fix p2p topic canonicalization and stale subscriptions

server/pres.go

@@ -50,15 +50,8 @@ func (t *Topic) addToPerSubs(topic string, online, enabled bool) {
 	}
 
 	// TODO: maybe skip loading channel subscriptions. They can's send or receive these notifications anyway.
-
-	if uid1, uid2, err := types.ParseP2P(topic); err == nil {
-		// If this is a P2P topic, index it by second user's ID
-		if uid1.UserId() == t.name {
-			topic = uid2.UserId()
-		} else {
-			topic = uid1.UserId()
-		}
-	}
+	// Keep the canonical P2P topic as the key. usr... is accepted only as a
+	// client input alias, while downlink frames should consistently use p2p....
 
 	t.perSubs[topic] = perSubsData{online: online, enabled: enabled}
 }
@@ -544,7 +537,6 @@ func (t *Topic) infoCallSubsOffline(from string, target types.Uid, event string,
 func presSubsOfflineOffline(tenantID types.TenantID, topic string, cat types.TopicCat, subs []types.Subscription, what string,
 	params *presParams, skipSid string) {
 
-	count := 0
 	original := topic
 	for i := range subs {
 		sub := &subs[i]
@@ -554,11 +546,6 @@ func presSubsOfflineOffline(tenantID types.TenantID, topic string, cat types.Top
 			continue
 		}
 
-		if cat == types.TopicCatP2P {
-			original = types.ParseUid(subs[(count+1)%2].User).UserId()
-			count++
-		}
-
 		user := types.ParseUid(sub.User).UserId()
 		actor := params.actor
 		target := params.target