Add flags for mismatch type to client desync log

src/crashlog.cpp

@@ -449,12 +449,22 @@ char *CrashLog::FillCrashLog(char *buffer, const char *last) const
  * @param last   The last position in the buffer to write to.
  * @return the position of the \c '\0' character after the buffer.
  */
-char *CrashLog::FillDesyncCrashLog(char *buffer, const char *last) const
+char *CrashLog::FillDesyncCrashLog(char *buffer, const char *last, const DesyncExtraInfo &info) const
 {
 	time_t cur_time = time(nullptr);
 	buffer += seprintf(buffer, last, "*** OpenTTD Multiplayer %s Desync Report ***\n\n", _network_server ? "Server" : "Client");
 
 	buffer += seprintf(buffer, last, "Desync at: %s", asctime(gmtime(&cur_time)));
+	if (!_network_server && info.flags) {
+		auto flag_check = [&](DesyncExtraInfo::Flags flag, const char *str) {
+			return info.flags & flag ? str : "";
+		};
+		buffer += seprintf(buffer, last, "Flags: %s%s%s%s\n",
+				flag_check(DesyncExtraInfo::DEIF_RAND1, "R"),
+				flag_check(DesyncExtraInfo::DEIF_RAND2, "Z"),
+				flag_check(DesyncExtraInfo::DEIF_STATE, "S"),
+				flag_check(DesyncExtraInfo::DEIF_DBL_RAND, "D"));
+	}
 
 	YearMonthDay ymd;
 	ConvertDateToYMD(_date, &ymd);
@@ -627,7 +637,7 @@ bool CrashLog::MakeCrashLog() const
  * information like paths to the console.
  * @return true when everything is made successfully.
  */
-bool CrashLog::MakeDesyncCrashLog(const std::string *log_in, std::string *log_out) const
+bool CrashLog::MakeDesyncCrashLog(const std::string *log_in, std::string *log_out, const DesyncExtraInfo &info) const
 {
 	char filename[MAX_PATH];
 	char buffer[65536 * 2];
@@ -641,7 +651,7 @@ bool CrashLog::MakeDesyncCrashLog(const std::string *log_in, std::string *log_ou
 	strftime(name_buffer_date, lastof(name_buffer) - name_buffer_date, "%Y%m%dT%H%M%SZ", gmtime(&cur_time));
 
 	printf("Desync encountered (%s), generating desync log...\n", mode);
-	char *b = this->FillDesyncCrashLog(buffer, lastof(buffer));
+	char *b = this->FillDesyncCrashLog(buffer, lastof(buffer), info);
 
 	if (log_in && !log_in->empty()) {
 		b = strecpy(b, "\n", lastof(buffer), true);

src/crashlog.h

@@ -12,8 +12,22 @@
 #ifndef CRASHLOG_H
 #define CRASHLOG_H
 
+#include "core/enum_type.hpp"
 #include <string>
 
+struct DesyncExtraInfo {
+	enum Flags {
+		DEIF_NONE       = 0,      ///< no flags
+		DEIF_RAND1      = 1 << 0, ///< random 1 mismatch
+		DEIF_RAND2      = 1 << 1, ///< random 2 mismatch
+		DEIF_STATE      = 1 << 2, ///< state mismatch
+		DEIF_DBL_RAND   = 1 << 3, ///< double-seed sent
+	};
+
+	Flags flags = DEIF_NONE;
+};
+DECLARE_ENUM_AS_BIT_SET(DesyncExtraInfo::Flags)
+
 /**
  * Helper class for creating crash logs.
  */
@@ -113,7 +127,7 @@ public:
 	virtual ~CrashLog() {}
 
 	char *FillCrashLog(char *buffer, const char *last) const;
-	char *FillDesyncCrashLog(char *buffer, const char *last) const;
+	char *FillDesyncCrashLog(char *buffer, const char *last, const DesyncExtraInfo &info) const;
 	bool WriteCrashLog(const char *buffer, char *filename, const char *filename_last, const char *name = "crash") const;
 
 	/**
@@ -130,7 +144,7 @@ public:
 	bool WriteScreenshot(char *filename, const char *filename_last, const char *name = "crash") const;
 
 	bool MakeCrashLog() const;
-	bool MakeDesyncCrashLog(const std::string *log_in, std::string *log_out) const;
+	bool MakeDesyncCrashLog(const std::string *log_in, std::string *log_out, const DesyncExtraInfo &info) const;
 	bool MakeCrashSavegameAndScreenshot() const;
 
 	/**
@@ -140,7 +154,7 @@ public:
 	 */
 	static void InitialiseCrashLog();
 
-	static void DesyncCrashLog(const std::string *log_in, std::string *log_out);
+	static void DesyncCrashLog(const std::string *log_in, std::string *log_out, const DesyncExtraInfo &info);
 
 	static void SetErrorMessage(const char *message);
 	static void AfterCrashLogCleanup();

src/network/network_client.cpp

@@ -288,13 +288,21 @@ void ClientNetworkGameSocketHandler::ClientError(NetworkRecvStatus res)
 #else
 			if (_sync_seed_1 != _random.state[0] || _sync_state_checksum != _state_checksum.state) {
 #endif
+				DesyncExtraInfo info;
+				if (_sync_seed_1 != _random.state[0]) info.flags |= DesyncExtraInfo::DEIF_RAND1;
+#ifdef NETWORK_SEND_DOUBLE_SEED
+				if (_sync_seed_2 != _random.state[1]) info.flags |= DesyncExtraInfo::DEIF_RAND2;
+				info.flags |= DesyncExtraInfo::DEIF_DBL_RAND;
+#endif
+				if (_sync_state_checksum != _state_checksum.state) info.flags |= DesyncExtraInfo::DEIF_STATE;
+
 				NetworkError(STR_NETWORK_ERROR_DESYNC);
 				DEBUG(desync, 1, "sync_err: date{%08x; %02x; %02x} {%x, " OTTD_PRINTFHEX64 "} != {%x, " OTTD_PRINTFHEX64 "}"
 						, _date, _date_fract, _tick_skip_counter, _sync_seed_1, _sync_state_checksum, _random.state[0], _state_checksum.state);
 				DEBUG(net, 0, "Sync error detected!");
 
 				std::string desync_log;
-				CrashLog::DesyncCrashLog(nullptr, &desync_log);
+				CrashLog::DesyncCrashLog(nullptr, &desync_log, info);
 				my_client->SendDesyncLog(desync_log);
 				my_client->ClientError(NETWORK_RECV_STATUS_DESYNC);
 				return false;

src/network/network_server.cpp

@@ -1214,7 +1214,7 @@ NetworkRecvStatus ServerNetworkGameSocketHandler::Receive_CLIENT_ERROR(Packet *p
 	NetworkAdminClientError(this->client_id, errorno);
 
 	if (errorno == NETWORK_ERROR_DESYNC) {
-		CrashLog::DesyncCrashLog(&(this->desync_log), nullptr);
+		CrashLog::DesyncCrashLog(&(this->desync_log), nullptr, DesyncExtraInfo{});
 
 		// decrease the sync frequency for this point onwards
 		_settings_client.network.sync_freq = min<uint16>(_settings_client.network.sync_freq, 16);

src/os/macosx/crashlog_osx.cpp

@@ -516,8 +516,8 @@ void CDECL HandleCrash(int signum, siginfo_t *si, void *context)
 	}
 }
 
-/* static */ void CrashLog::DesyncCrashLog(const std::string *log_in, std::string *log_out)
+/* static */ void CrashLog::DesyncCrashLog(const std::string *log_in, std::string *log_out, const DesyncExtraInfo &info)
 {
 	CrashLogOSX log(CrashLogOSX::DesyncTag{});
-	log.MakeDesyncCrashLog(log_in, log_out);
+	log.MakeDesyncCrashLog(log_in, log_out, info);
 }

src/os/unix/crashlog_unix.cpp

@@ -620,8 +620,8 @@ static void CDECL HandleCrash(int signum)
 	}
 }
 
-/* static */ void CrashLog::DesyncCrashLog(const std::string *log_in, std::string *log_out)
+/* static */ void CrashLog::DesyncCrashLog(const std::string *log_in, std::string *log_out, const DesyncExtraInfo &info)
 {
 	CrashLogUnix log(CrashLogUnix::DesyncTag{});
-	log.MakeDesyncCrashLog(log_in, log_out);
+	log.MakeDesyncCrashLog(log_in, log_out, info);
 }

src/os/windows/crashlog_win.cpp

@@ -612,10 +612,10 @@ static void CDECL CustomAbort(int signal)
 	SetUnhandledExceptionFilter(ExceptionHandler);
 }
 
-/* static */ void CrashLog::DesyncCrashLog(const std::string *log_in, std::string *log_out)
+/* static */ void CrashLog::DesyncCrashLog(const std::string *log_in, std::string *log_out, const DesyncExtraInfo &info)
 {
 	CrashLogWindows log(nullptr);
-	log.MakeDesyncCrashLog(log_in, log_out);
+	log.MakeDesyncCrashLog(log_in, log_out, info);
 }
 
 /* The crash log GUI */