Do not invite players who are already in the group.

src/net/common/servergame.cpp

@@ -464,6 +464,12 @@ ServerGame::IsPlayerConnected(const std::string &name) const
 	return GetSessionManager().IsPlayerConnected(name);
 }
 
+bool
+ServerGame::IsPlayerConnected(unsigned playerId) const
+{
+	return GetSessionManager().IsPlayerConnected(playerId);
+}
+
 bool
 ServerGame::IsRunning() const
 {
@@ -487,6 +493,8 @@ ServerGame::AddPlayerInvitation(unsigned playerId)
 {
 	boost::mutex::scoped_lock lock(m_playerInvitationListMutex);
 	m_playerInvitationList.push_back(playerId);
+	m_playerInvitationList.sort();
+	m_playerInvitationList.unique();
 }
 
 void

src/net/common/servergamestate.cpp

@@ -467,7 +467,8 @@ ServerGameStateInit::InternalProcessPacket(boost::shared_ptr<ServerGame> server,
 	{
 		InvitePlayerToGameMessage_t *netInvite = &packet->GetMsg()->choice.invitePlayerToGameMessage;
 
-		if (netInvite->gameId == server->GetId())
+		// Only invite players which are not already within the group.
+		if (netInvite->gameId == server->GetId() && !server->IsPlayerConnected(netInvite->playerId))
 		{
 			boost::shared_ptr<NetPacket> packet(new NetPacket(NetPacket::Alloc));
 			packet->GetMsg()->present = PokerTHMessage_PR_inviteNotifyMessage;

src/net/servergame.h

@@ -72,6 +72,7 @@ public:
 	boost::shared_ptr<PlayerData> GetPlayerDataByUniqueId(unsigned playerId) const;
 	PlayerIdList GetPlayerIdList() const;
 	bool IsPlayerConnected(const std::string &name) const;
+	bool IsPlayerConnected(unsigned playerId) const;
 
 	bool IsRunning() const;