bugfix(crc): Fix spurious mismatches for disconnected players at low CRC intervals (TheSuperHackers#2796)

Author: Caball009

Generals/Code/GameEngine/Include/GameLogic/GameLogic.h

@@ -383,7 +383,8 @@ class GameLogic : public SubsystemInterface, public Snapshot
 
 	// CRC cache system -----------------------------------------------------------------------------
 	UnsignedInt	m_CRC;																			///< Cache of previous CRC value
-	std::map<Int, UnsignedInt> m_cachedCRCs;								///< CRCs we've seen this frame
+	typedef std::map<Int, UnsignedInt> CachedCRCMap;
+	CachedCRCMap m_cachedCRCs;															///< CRCs we've seen this frame
 	Bool m_shouldValidateCRCs;															///< Should we validate CRCs this frame?
 	//-----------------------------------------------------------------------------------------------
 	//Bool m_loadingScene;

Generals/Code/GameEngine/Source/GameLogic/System/GameLogic.cpp

@@ -2338,15 +2338,26 @@ void GameLogic::processCommandList( CommandList *list )
 			}
 			else
 			{
-				//DEBUG_LOG(("Comparing %d CRCs on frame %d", m_cachedCRCs.size(), m_frame));
-				std::map<Int, UnsignedInt>::const_iterator crcIt = m_cachedCRCs.begin();
-				Int validatorCRC = crcIt->second;
-				//DEBUG_LOG(("Validator CRC from player %d is %8.8X", crcIt->first, validatorCRC));
-				while (++crcIt != m_cachedCRCs.end())
+				Bool hasReferenceCRC = FALSE;
+				UnsignedInt referenceCRC = 0;
+
+				for (CachedCRCMap::const_iterator it = m_cachedCRCs.begin(); it != m_cachedCRCs.end(); ++it)
 				{
-					Int validatedCRC = crcIt->second;
-					//DEBUG_LOG(("CRC to validate is from player %d: %8.8X", crcIt->first, validatedCRC));
-					if (validatorCRC != validatedCRC)
+					// TheSuperHackers @bugfix Caball009 14/06/2026 Check if player is still connected,
+					// to avoid spurious mismatches at low CRC intervals, e.g. every frame.
+					if (!TheNetwork->isPlayerConnected(it->first))
+						continue;
+
+					const UnsignedInt crc = it->second;
+
+					if (!hasReferenceCRC)
+					{
+						hasReferenceCRC = TRUE;
+						referenceCRC = crc;
+						continue;
+					}
+
+					if (referenceCRC != crc)
 					{
 						DEBUG_CRASH(("CRC mismatch!"));
 						sawCRCMismatch = TRUE;
@@ -2359,7 +2370,7 @@ void GameLogic::processCommandList( CommandList *list )
 		{
 #ifdef DEBUG_LOGGING
 			DEBUG_LOG(("CRC Mismatch - saw %d CRCs from %d players", m_cachedCRCs.size(), numPlayers));
-			for (std::map<Int, UnsignedInt>::const_iterator crcIt = m_cachedCRCs.begin(); crcIt != m_cachedCRCs.end(); ++crcIt)
+			for (CachedCRCMap::const_iterator crcIt = m_cachedCRCs.begin(); crcIt != m_cachedCRCs.end(); ++crcIt)
 			{
 				Player *player = ThePlayerList->getNthPlayer(crcIt->first);
 				DEBUG_LOG(("CRC from player %d (%ls) = %X", crcIt->first,

GeneralsMD/Code/GameEngine/Include/GameLogic/GameLogic.h

@@ -390,7 +390,8 @@ class GameLogic : public SubsystemInterface, public Snapshot
 
 	// CRC cache system -----------------------------------------------------------------------------
 	UnsignedInt	m_CRC;																			///< Cache of previous CRC value
-	std::map<Int, UnsignedInt> m_cachedCRCs;								///< CRCs we've seen this frame
+	typedef std::map<Int, UnsignedInt> CachedCRCMap;
+	CachedCRCMap m_cachedCRCs;															///< CRCs we've seen this frame
 	Bool m_shouldValidateCRCs;															///< Should we validate CRCs this frame?
 	//-----------------------------------------------------------------------------------------------
 	//Bool m_loadingScene;

GeneralsMD/Code/GameEngine/Source/GameLogic/System/GameLogic.cpp

@@ -2664,15 +2664,26 @@ void GameLogic::processCommandList( CommandList *list )
 			}
 			else
 			{
-				//DEBUG_LOG(("Comparing %d CRCs on frame %d", m_cachedCRCs.size(), m_frame));
-				std::map<Int, UnsignedInt>::const_iterator crcIt = m_cachedCRCs.begin();
-				Int validatorCRC = crcIt->second;
-				//DEBUG_LOG(("Validator CRC from player %d is %8.8X", crcIt->first, validatorCRC));
-				while (++crcIt != m_cachedCRCs.end())
+				Bool hasReferenceCRC = FALSE;
+				UnsignedInt referenceCRC = 0;
+
+				for (CachedCRCMap::const_iterator it = m_cachedCRCs.begin(); it != m_cachedCRCs.end(); ++it)
 				{
-					Int validatedCRC = crcIt->second;
-					//DEBUG_LOG(("CRC to validate is from player %d: %8.8X", crcIt->first, validatedCRC));
-					if (validatorCRC != validatedCRC)
+					// TheSuperHackers @bugfix Caball009 14/06/2026 Check if player is still connected,
+					// to avoid spurious mismatches at low CRC intervals, e.g. every frame.
+					if (!TheNetwork->isPlayerConnected(it->first))
+						continue;
+
+					const UnsignedInt crc = it->second;
+
+					if (!hasReferenceCRC)
+					{
+						hasReferenceCRC = TRUE;
+						referenceCRC = crc;
+						continue;
+					}
+
+					if (referenceCRC != crc)
 					{
 						DEBUG_CRASH(("CRC mismatch!"));
 						sawCRCMismatch = TRUE;
@@ -2685,7 +2696,7 @@ void GameLogic::processCommandList( CommandList *list )
 		{
 #ifdef DEBUG_LOGGING
 			DEBUG_LOG(("CRC Mismatch - saw %d CRCs from %d players", m_cachedCRCs.size(), numPlayers));
-			for (std::map<Int, UnsignedInt>::const_iterator crcIt = m_cachedCRCs.begin(); crcIt != m_cachedCRCs.end(); ++crcIt)
+			for (CachedCRCMap::const_iterator crcIt = m_cachedCRCs.begin(); crcIt != m_cachedCRCs.end(); ++crcIt)
 			{
 				Player *player = ThePlayerList->getNthPlayer(crcIt->first);
 				DEBUG_LOG(("CRC from player %d (%ls) = %X", crcIt->first,