From 9ce8202eb15afda65aba4447be8145066f801784 Mon Sep 17 00:00:00 2001
From: Christoph Oelckers <coelckers@users.noreply.github.com>
Date: Thu, 10 Sep 2020 21:39:52 +0200
Subject: [PATCH] - Duke: Added a file check for the map to be entered when
 ending a level.

World Tour contains a map definition for E5L9 but no map for it.
---
 source/build/src/clip.cpp        | 2 ++
 source/games/duke/src/premap.cpp | 8 ++++++++
 2 files changed, 10 insertions(+)

diff --git a/source/build/src/clip.cpp b/source/build/src/clip.cpp
index 030c2d704..1b460f784 100644
--- a/source/build/src/clip.cpp
+++ b/source/build/src/clip.cpp
@@ -399,11 +399,13 @@ static int get_floorspr_clipyou(vec2_t const v1, vec2_t const v2, vec2_t const v
 
 static void clipupdatesector(vec2_t const pos, int16_t * const sectnum, int walldist)
 {
+#if 0
     if (enginecompatibility_mode != ENGINECOMPATIBILITY_NONE)
     {
         updatesector(pos.x, pos.y, sectnum);
         return;
     }
+#endif
 
     if (inside_p(pos.x, pos.y, *sectnum))
         return;
diff --git a/source/games/duke/src/premap.cpp b/source/games/duke/src/premap.cpp
index 5d4b45b3d..f0c517c26 100644
--- a/source/games/duke/src/premap.cpp
+++ b/source/games/duke/src/premap.cpp
@@ -1046,8 +1046,16 @@ bool setnextmap(bool checksecretexit)
         map = FindNextMap(currentLevel);
     }
 
+    // Make sure these two are cleared in case the map check errors out.
+    ud.from_bonus = 0;
+    ud.secretlevel = 0;
     if (map)
     {
+        // If the map doesn't exist, abort with a meaningful message instead of crashing.
+        if (fileSystem.FindFile(map->fileName) < 0)
+        {
+            I_Error("Trying to open non-existent %s", map->fileName.GetChars());
+        }
         ud.from_bonus = from_bonus;
     }
     CompleteLevel(map);