Check whether DoCommand test execution changes the random seed

src/command.cpp

@@ -29,6 +29,7 @@
 #include "newgrf_text.h"
 #include "string_func.h"
 #include "scope_info.h"
+#include "core/random_func.hpp"
 #include <array>
 
 #include "table/strings.h"
@@ -921,6 +922,8 @@ CommandCost DoCommandPInternal(TileIndex tile, uint32 p1, uint32 p2, uint32 cmd,
 
 	bool test_and_exec_can_differ = (cmd_flags & CMD_NO_TEST) != 0;
 
+	GameRandomSeedChecker random_state;
+
 	/* Test the command. */
 	_cleared_object_areas.clear();
 	SetTownRatingTestMode(true);
@@ -929,6 +932,11 @@ CommandCost DoCommandPInternal(TileIndex tile, uint32 p1, uint32 p2, uint32 cmd,
 	BasePersistentStorageArray::SwitchMode(PSM_LEAVE_TESTMODE);
 	SetTownRatingTestMode(false);
 
+	if (!random_state.Check()) {
+		DEBUG(desync, 0, "Random seed changed in test command: date{%08x; %02x; %02x}; company: %02x; tile: %06x (%u x %u); p1: %08x; p2: %08x; cmd: %08x; \"%s\" %X (%s)",
+				_date, _date_fract, _tick_skip_counter, (int)_current_company, tile, TileX(tile), TileY(tile), p1, p2, cmd & ~CMD_NETWORK_COMMAND, text, binary_length, GetCommandName(cmd));
+	}
+
 	/* Make sure we're not messing things up here. */
 	assert(exec_as_spectator ? _current_company == COMPANY_SPECTATOR : cur_company.Verify());
 

src/core/random_func.hpp

@@ -49,7 +49,7 @@ static inline void SaveRandomSeeds(SavedRandomSeeds *storage)
 
 /**
  * Restores previously saved seeds
- * @param storage Storage where SaveRandomSeeds() stored th seeds
+ * @param storage Storage where SaveRandomSeeds() stored the seeds
  */
 static inline void RestoreRandomSeeds(const SavedRandomSeeds &storage)
 {
@@ -57,6 +57,22 @@ static inline void RestoreRandomSeeds(const SavedRandomSeeds &storage)
 	_interactive_random = storage.interactive_random;
 }
 
+struct GameRandomSeedChecker {
+private:
+	Randomizer random;
+
+public:
+	GameRandomSeedChecker()
+	{
+		this->random = _random;
+	}
+
+	bool Check() const
+	{
+		return (this->random.state[0] == _random.state[0] && this->random.state[1] == _random.state[1]);
+	}
+};
+
 void SetRandomSeed(uint32 seed);
 #ifdef RANDOM_DEBUG
 	#ifdef __APPLE__