Merge #3341

3341: Check finish of team after player joins spectators r=heinrich5991 a=def-

Reported by Jupeyy

<!-- What is the motivation for the changes of this pull request -->

## Checklist

- [x] Tested the change ingame
- [ ] Provided screenshots if it is a visual change
- [ ] Tested in combination with possibly related configuration options
- [ ] Written a unit test if it works standalone, system.c especially
- [x] Considered possible null pointers and out of bounds array indexing
- [x] Changed no physics that affect existing maps
- [x] Tested the change with [ASan+UBSan or valgrind's memcheck](https://github.com/ddnet/ddnet/#using-addresssanitizer--undefinedbehavioursanitizer-or-valgrinds-memcheck) (optional)


Co-authored-by: def <dennis@felsin9.de>

src/game/server/player.cpp

@@ -631,7 +631,13 @@ void CPlayer::SetTeam(int Team, bool DoChatMsg)
 	{
 		CGameControllerDDRace *Controller = (CGameControllerDDRace *)GameServer()->m_pController;
 		if(g_Config.m_SvTeam != 3)
+		{
+			// Joining spectators should not kill a locked team, but should still
+			// check if the team finished by you leaving it.
+			int DDRTeam = m_pCharacter->Team();
 			Controller->m_Teams.SetForceCharacterTeam(m_ClientID, TEAM_FLOCK);
+			Controller->m_Teams.CheckTeamFinished(DDRTeam);
+		}
 	}
 
 	KillCharacter();

src/game/server/teams.h

@@ -19,7 +19,6 @@ class CGameTeams
 
 	class CGameContext *m_pGameContext;
 
-	void CheckTeamFinished(int ClientID);
 	bool TeamFinished(int Team);
 	void OnTeamFinish(CPlayer **Players, unsigned int Size, float Time, const char *pTimestamp);
 	void OnFinish(CPlayer *Player, float Time, const char *pTimestamp);
@@ -62,6 +61,7 @@ public:
 	void OnCharacterDeath(int ClientID, int Weapon);
 
 	bool SetCharacterTeam(int ClientID, int Team);
+	void CheckTeamFinished(int ClientID);
 
 	void ChangeTeamState(int Team, int State);
 	void onChangeTeamState(int Team, int State, int OldState);