From 61c1fc08abb9e9fbfecf6bcfb464a09a8214e1a1 Mon Sep 17 00:00:00 2001
From: Eduardo Dantas <eduardo.dantas@hotmail.com.br>
Date: Sat, 14 Dec 2024 01:53:28 -0300
Subject: [PATCH] fix: infinite loop in Zone:randomPosition when no valid tile
 exist (#3178)

This commit fixes an infinite loop issue in the `Zone:randomPosition`
function. When no valid positions (walkable tiles) exist in the zone,
the function would previously enter an infinite loop. The updated logic
now filters all positions upfront to identify walkable tiles, and if
none are found, the function returns `nil` with appropriate logging.
This change ensures better error handling and prevents server freezes
due to infinite loops.
---
 data/libs/systems/zones.lua | 22 +++++++++++++++++-----
 1 file changed, 17 insertions(+), 5 deletions(-)

diff --git a/data/libs/systems/zones.lua b/data/libs/systems/zones.lua
index 698a464fe87..a232a071f41 100644
--- a/data/libs/systems/zones.lua
+++ b/data/libs/systems/zones.lua
@@ -15,12 +15,24 @@ function Zone:randomPosition()
 		logger.error("Zone:randomPosition() - Zone {} has no positions", self:getName())
 		return nil
 	end
-	local destination = positions[math.random(1, #positions)]
-	local tile = destination:getTile()
-	while not tile or not tile:isWalkable(false, false, false, false, true) do
-		destination = positions[math.random(1, #positions)]
-		tile = destination:getTile()
+
+	local validPositions = {}
+	for _, position in ipairs(positions) do
+		local tile = position:getTile()
+		if tile and tile:isWalkable(false, false, false, false, true) then
+			table.insert(validPositions, position)
+		else
+			logger.debug("Zone:randomPosition() - Position {} is invalid (Tile: {}, Walkable: {})", position, tile or "nil", tile and tile:isWalkable(false, false, false, false, true) or "false")
+		end
 	end
+
+	if #validPositions == 0 then
+		logger.error("Zone:randomPosition() - No valid positions in Zone {}", self:getName())
+		return nil
+	end
+
+	local destination = validPositions[math.random(1, #validPositions)]
+	logger.debug("Zone:randomPosition() - Selected valid position: {}", destination)
 	return destination
 end