Pre-emptive fixes for custom gametypes

- Handle mismatched gametypes for client and server on voting screen
- I_Error when running out of gametypes
- Reduce gametype freeslots slightly to avoid colliding with VOTEMODIFIER_ENCORE

src/d_netcmd.c

@@ -5313,6 +5313,24 @@ static void Got_SetupVotecmd(UINT8 **cp, INT32 playernum)
 		gt &= ~VOTEMODIFIER_ENCORE;
 	}
 
+	if ((gt & ~VOTEMODIFIER_ENCORE) >= gametypecount)
+	{
+		gt &= ~VOTEMODIFIER_ENCORE;
+		if (server)
+			I_Error("Got_SetupVotecmd: Internal gametype ID %d not found (gametypecount = %d)", gt, gametypecount);
+		CONS_Alert(CONS_WARNING, M_GetText("Vote setup with bad gametype ID %d received from %s\n"), gt, player_names[playernum]);
+		return;
+	}
+
+	if ((secondgt & ~VOTEMODIFIER_ENCORE) >= gametypecount)
+	{
+		secondgt &= ~VOTEMODIFIER_ENCORE;
+		if (server)
+			I_Error("Got_SetupVotecmd: Internal second gametype ID %d not found (gametypecount = %d)", secondgt, gametypecount);
+		CONS_Alert(CONS_WARNING, M_GetText("Vote setup with bad second gametype ID %d received from %s\n"), secondgt, player_names[playernum]);
+		return;
+	}
+
 	for (i = 0; i < 4; i++)
 	{
 		tempvotelevels[i][0] = (UINT16)READUINT16(*cp);

src/deh_soc.c

@@ -881,7 +881,7 @@ void readgametype(MYFILE *f, char *gtname)
 	// Ran out of gametype slots
 	if (gametypecount == NUMGAMETYPEFREESLOTS)
 	{
-		CONS_Alert(CONS_WARNING, "Ran out of free gametype slots!\n");
+		I_Error("Out of Gametype Freeslots while allocating \"%s\"\nLoad less addons to fix this.", gtname);
 		return;
 	}
 

src/doomstat.h

@@ -454,7 +454,7 @@ extern mapheader_t** mapheaderinfo;
 extern INT32 nummapheaders, mapallocsize;
 
 // Gametypes
-#define NUMGAMETYPEFREESLOTS 128
+#define NUMGAMETYPEFREESLOTS (NUMGAMETYPES-GT_FIRSTFREESLOT)
 
 enum GameType
 {
@@ -462,7 +462,7 @@ enum GameType
 	GT_BATTLE,
 
 	GT_FIRSTFREESLOT,
-	GT_LASTFREESLOT = GT_FIRSTFREESLOT + NUMGAMETYPEFREESLOTS - 1,
+	GT_LASTFREESLOT = 127, // Previously (GT_FIRSTFREESLOT + NUMGAMETYPEFREESLOTS - 1) - it would be necessary to rewrite VOTEMODIFIER_ENCORE to go higher than this.
 	NUMGAMETYPES
 };
 // If you alter this list, update deh_tables.c, MISC_ChangeGameTypeMenu in m_menu.c, and Gametype_Names in g_game.c