fix: populate channels with all members for existing communities

protocol/communities/community.go

@@ -1903,6 +1903,39 @@ func (o *Community) AddMemberToChat(chatID string, publicKey *ecdsa.PublicKey, r
 	return changes, nil
 }
 
+func (o *Community) PopulateChatWithAllMembers(chatID string) (*CommunityChanges, error) {
+	o.mutex.Lock()
+	defer o.mutex.Unlock()
+
+	if !o.IsControlNode() {
+		return o.emptyCommunityChanges(), ErrNotControlNode
+	}
+
+	return o.populateChatWithAllMembers(chatID)
+}
+
+func (o *Community) populateChatWithAllMembers(chatID string) (*CommunityChanges, error) {
+	result := o.emptyCommunityChanges()
+
+	chat, exists := o.chats()[chatID]
+	if !exists {
+		return result, ErrChatNotFound
+	}
+
+	membersAdded := make(map[string]*protobuf.CommunityMember)
+	for pubKey, member := range o.Members() {
+		if chat.Members[pubKey] == nil {
+			membersAdded[pubKey] = member
+		}
+	}
+	result.ChatsModified[chatID] = &CommunityChatChanges{
+		MembersAdded: membersAdded,
+	}
+
+	chat.Members = o.Members()
+	return result, nil
+}
+
 func (o *Community) ChatIDs() (chatIDs []string) {
 	for id := range o.config.CommunityDescription.Chats {
 		chatIDs = append(chatIDs, o.IDString()+id)

protocol/communities/manager.go

@@ -243,6 +243,11 @@ func NewManager(identity *ecdsa.PrivateKey, db *sql.DB, encryptor *encryption.Pr
 		manager.ensVerifier = verifier
 	}
 
+	err = manager.fixupChannelMembers()
+	if err != nil {
+		return nil, errors.Wrap(err, "failed to fixup channel members")
+	}
+
 	return manager, nil
 }
 
@@ -4113,3 +4118,34 @@ func (m *Manager) saveAndPublish(community *Community) error {
 
 	return nil
 }
+
+// This populates the member list of channels with all community members, if required.
+// Motivation: The member lists of channels were not populated for communities that had already been created.
+//
+// Ideally, this should be executed through a migration, but it's technically unfeasible
+// because `CommunityDescription“ is stored as a signed message blob in the database.
+//
+// However, it's safe to run this migration/fixup multiple times.
+func (m *Manager) fixupChannelMembers() error {
+	controlledCommunities, err := m.Created()
+	if err != nil {
+		return err
+	}
+
+	for _, c := range controlledCommunities {
+		for channelID := range c.Chats() {
+			if !c.ChannelHasTokenPermissions(c.IDString() + channelID) {
+				_, err := c.PopulateChatWithAllMembers(channelID)
+				if err != nil {
+					return err
+				}
+				err = m.persistence.SaveCommunity(c)
+				if err != nil {
+					return err
+				}
+			}
+		}
+	}
+
+	return nil
+}