From 438b661494e9a59734c5df32f014984240e622f0 Mon Sep 17 00:00:00 2001
From: Celtic Minstrel <celtic.minstrel.ca@some.place>
Date: Mon, 15 Feb 2021 18:35:42 -0500
Subject: [PATCH] Avoid map borders in cave generator

Addresses #5407
---
 data/lua/cave_map_generator.lua | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/data/lua/cave_map_generator.lua b/data/lua/cave_map_generator.lua
index 279622f3aa1e..962d1df4feff 100644
--- a/data/lua/cave_map_generator.lua
+++ b/data/lua/cave_map_generator.lua
@@ -122,6 +122,10 @@ function callbacks.generate_map(params)
 			local width = math.max(v.data.width or 1, 1)
 			local jagged = v.data.jagged or 0
 			local calc = function(x, y)
+				if x == 0 or x == params.map_width or y == 0 or y == params.map_height then
+					-- Map borders are impassable
+					return math.huge
+				end
 				local res = 1.0
 				if map:get_tile(x, y) == params.terrain_wall then
 					res = laziness