fix: resolve nil value errors in handleGuildWar function (#3172)

I made corrections to the `death.lua` script to resolve nil value errors
in the `handleGuildWar` function. I added checks to ensure that both the
player and the killer are valid and that both belong to a guild before
proceeding with the guild war logic. This helps prevent failures when
one of the objects is undefined.

Fixes from: 3c98b41

Author: Marco

data/scripts/creaturescripts/player/death.lua

@@ -48,7 +48,7 @@ end
 
 local function saveDeathRecord(playerGuid, player, killerName, byPlayer, mostDamageName, byPlayerMostDamage, unjustified, mostDamageUnjustified)
 	local query = string.format(
-		"INSERT INTO `player_deaths` (`player_id`, `time`, `level`, `killed_by`, `is_player`, `mostdamage_by`, `mostdamage_is_player`, `unjustified`, `mostdamage_unjustified`) " .. "VALUES (%d, %d, %d, '%s', %d, '%s', %d, %d, %d)",
+		"INSERT INTO `player_deaths` (`player_id`, `time`, `level`, `killed_by`, `is_player`, `mostdamage_by`, `mostdamage_is_player`, `unjustified`, `mostdamage_unjustified`) " .. "VALUES (%d, %d, %d, %s, %d, %s, %d, %d, %d)",
 		playerGuid,
 		os.time(),
 		player:getLevel(),
@@ -62,23 +62,6 @@ local function saveDeathRecord(playerGuid, player, killerName, byPlayer, mostDam
 	db.query(query)
 end
 
-local function handleGuildWar(player, killer, mostDamageKiller, killerName, mostDamageName)
-	local deathRecords = getDeathRecords(player:getGuid())
-
-	if deathRecords > 0 then
-		local targetGuildId = player:getGuild() and player:getGuild():getId() or 0
-		local killerGuildId = killer:getGuild() and killer:getGuild():getId() or 0
-
-		if targetGuildId ~= 0 and killerGuildId ~= 0 and targetGuildId ~= killerGuildId then
-			local warId = checkForGuildWar(targetGuildId, killerGuildId)
-			if warId then
-				recordGuildWarKill(killer, player, killerGuildId, targetGuildId, warId)
-				checkAndUpdateGuildWarScore(warId, targetGuildId, killerGuildId, player:getName(), killerName, mostDamageName)
-			end
-		end
-	end
-end
-
 local function getDeathRecords(playerGuid)
 	local resultId = db.storeQuery("SELECT `player_id` FROM `player_deaths` WHERE `player_id` = " .. playerGuid)
 	local deathRecords = 0
@@ -94,6 +77,27 @@ local function getDeathRecords(playerGuid)
 	return deathRecords
 end
 
+local function handleGuildWar(player, killer, mostDamageKiller, killerName, mostDamageName)
+	if not player or not killer or not killer:isPlayer() or not player:getGuild() or not killer:getGuild() then
+		return
+	end
+
+	local playerGuildId = player:getGuild():getId()
+	local killerGuildId = killer:getGuild():getId()
+
+	if playerGuildId == killerGuildId then
+		return
+	end
+
+	if getDeathRecords(player:getGuid()) > 0 then
+		local warId = checkForGuildWar(playerGuildId, killerGuildId)
+		if warId then
+			recordGuildWarKill(killer, player, killerGuildId, playerGuildId, warId)
+			checkAndUpdateGuildWarScore(warId, playerGuildId, killerGuildId, player:getName(), killerName, mostDamageName)
+		end
+	end
+end
+
 local function checkForGuildWar(targetGuildId, killerGuildId)
 	local resultId = db.storeQuery(string.format("SELECT `id` FROM `guild_wars` WHERE `status` = 1 AND ((`guild1` = %d AND `guild2` = %d) OR (`guild1` = %d AND `guild2` = %d))", killerGuildId, targetGuildId, targetGuildId, killerGuildId))