fix: loop in movement "stepin/out" and "addItem/remove" events

data/npclib/npc_system/modules.lua

@@ -223,16 +223,12 @@ if Modules == nil then
 		else
 			npcHandler:removeInteraction(npc, player)
 			npcHandler:say(parameters.text or "Set the sails!", npc, player)
-			playerPosition:sendMagicEffect(CONST_ME_TELEPORT)
 
 			local destination = parameters.destination
 			if type(destination) == 'function' then
 				destination = destination(player)
 			end
 
-			player:teleportTo(destination)
-			playerPosition:sendMagicEffect(CONST_ME_TELEPORT)
-
 			player:setStorageValue(NpcExhaust, 3 + os.time())
 			player:teleportTo(destination)
 			playerPosition:sendMagicEffect(CONST_ME_TELEPORT)

src/game/game.cpp

@@ -2135,7 +2135,9 @@ ReturnValue Game::internalTeleport(Thing* thing, const Position& newPos, bool pu
 		return RETURNVALUE_NOTPOSSIBLE;
 	}
 
-	if (thing->isRemoved()) {
+	if (newPos == thing->getPosition()) {
+		return RETURNVALUE_CONTACTADMINISTRATOR;
+	} else if (thing->isRemoved()) {
 		return RETURNVALUE_NOTPOSSIBLE;
 	}
 

src/lua/creature/movement.cpp

@@ -262,7 +262,6 @@ MoveEvent* MoveEvents::getEvent(Tile& tile, MoveEvent_t eventType) {
 
 uint32_t MoveEvents::onCreatureMove(Creature& creature, Tile& tile, MoveEvent_t eventType) {
 	const Position& pos = tile.getPosition();
-
 	uint32_t ret = 1;
 
 	MoveEvent *moveEvent = getEvent(tile, eventType);
@@ -283,7 +282,12 @@ uint32_t MoveEvents::onCreatureMove(Creature& creature, Tile& tile, MoveEvent_t
 
 		moveEvent = getEvent(*tileItem, eventType);
 		if (moveEvent) {
-			ret &= moveEvent->fireStepEvent(creature, tileItem, pos);
+			auto step = moveEvent->fireStepEvent(creature, tileItem, pos);
+			// If there is any problem in the function, we will kill the loop
+			if (step == 0) {
+				break;
+			}
+			ret &= step;
 		}
 	}
 	return ret;
@@ -341,7 +345,11 @@ uint32_t MoveEvents::onItemMove(Item& item, Tile& tile, bool isAdd) {
 
 		moveEvent = getEvent(*tileItem, eventType2);
 		if (moveEvent) {
-			ret &= moveEvent->fireAddRemItem(item, *tileItem, tile.getPosition());
+			auto moveItem = moveEvent->fireAddRemItem(item, *tileItem, tile.getPosition());
+			// If there is any problem in the function, we will kill the loop
+			if (moveItem == 0) {
+				break;
+			}
 		}
 
 	}
@@ -649,6 +657,23 @@ uint32_t MoveEvent::fireStepEvent(Creature& creature, Item* item, const Position
 bool MoveEvent::executeStep(Creature& creature, Item* item, const Position& pos) const {
 	//onStepIn(creature, item, pos, fromPosition)
 	//onStepOut(creature, item, pos, fromPosition)
+
+	// Check if the new position is the same as the old one
+	// If it is, log a warning and either teleport the player to their temple position if item type is an teleport
+	auto fromPosition = creature.getLastPosition();
+	if (auto player = creature.getPlayer(); item && fromPosition == pos && getEventType() == MOVE_EVENT_STEP_IN)
+	{
+		if (const ItemType& itemType = Item::items[item->getID()]; player && itemType.isTeleport())
+		{
+			SPDLOG_WARN("[{}] cannot teleport player: {}, to the same position: {} of fromPosition: {}", __FUNCTION__, player->getName(), pos.toString(), fromPosition.toString());
+			g_game().internalTeleport(player, player->getTemplePosition());
+			player->sendMagicEffect(player->getTemplePosition(), CONST_ME_TELEPORT);
+			player->sendCancelMessage(getReturnMessage(RETURNVALUE_CONTACTADMINISTRATOR));
+		}
+
+		return false;
+	}
+
 	if (!getScriptInterface()->reserveScriptEnv()) {
 		if (item != nullptr) {
 			SPDLOG_ERROR("[MoveEvent::executeStep - Creature {} item {}, position {}] "
@@ -674,7 +699,7 @@ bool MoveEvent::executeStep(Creature& creature, Item* item, const Position& pos)
 	LuaScriptInterface::setCreatureMetatable(L, -1, &creature);
 	LuaScriptInterface::pushThing(L, item);
 	LuaScriptInterface::pushPosition(L, pos);
-	LuaScriptInterface::pushPosition(L, creature.getLastPosition());
+	LuaScriptInterface::pushPosition(L, fromPosition);
 
 	return getScriptInterface()->callFunction(4);
 }

src/lua/functions/creatures/creature_functions.cpp

@@ -749,9 +749,25 @@ int CreatureFunctions::luaCreatureTeleportTo(lua_State* L) {
 		return 1;
 	}
 
+	const Player *player = creature->getPlayer();
+	if (!player) {
+		return 1;
+	}
+
 	const Position oldPosition = creature->getPosition();
-	if (g_game().internalTeleport(creature, position, pushMovement) != RETURNVALUE_NOERROR) {
-		SPDLOG_WARN("[{}] - Cannot teleport creature with name: {}, fromPosition {}, toPosition {}", __FUNCTION__, creature->getName(), oldPosition.toString(), position.toString());
+	if (oldPosition == position) {
+		SPDLOG_WARN("[{}] - Cannot teleport creature: {}, fromPosition: {}, as same of toPosition: {}", __FUNCTION__, player->getName(), oldPosition.toString(), position.toString());
+		player->sendCancelMessage(getReturnMessage(RETURNVALUE_CONTACTADMINISTRATOR));
+		pushBoolean(L, false);
+		reportErrorFunc("The new position is the same as the old one.");
+		return 1;
+	}
+
+	if (auto ret = g_game().internalTeleport(creature, position, pushMovement);
+		ret != RETURNVALUE_NOERROR)
+	{
+		player->sendCancelMessage(ret);
+		SPDLOG_ERROR("[{}] Failed to teleport player, error code: {}", __FUNCTION__, getReturnMessage(ret));
 		pushBoolean(L, false);
 		return 1;
 	}