From e37428d5cd3e7474b3ba1ec76d541a322f3a179c Mon Sep 17 00:00:00 2001
From: Pasi Kallinen <paxed@alt.org>
Date: Sat, 18 Mar 2023 08:51:33 +0200
Subject: [PATCH] Fix fuzzer teleporting out of Fort Ludios

---
 src/do.c       | 4 +++-
 src/dog.c      | 3 +++
 src/mklev.c    | 5 ++++-
 src/teleport.c | 1 +
 4 files changed, 11 insertions(+), 2 deletions(-)

diff --git a/src/do.c b/src/do.c
index f41e45db9..937f957ab 100644
--- a/src/do.c
+++ b/src/do.c
@@ -1635,7 +1635,9 @@ goto_level(
                 /* returning from tutorial via portal */
                 u_on_newpos(stway->sx, stway->sy);
             } else {
-                panic("goto_level: no corresponding portal!");
+                if (!iflags.debug_fuzzer)
+                    impossible("goto_level: no corresponding portal!");
+                u_on_rndspot(0);
             }
         } else {
             seetrap(ttrap);
diff --git a/src/dog.c b/src/dog.c
index 46510d395..8b97d5b86 100644
--- a/src/dog.c
+++ b/src/dog.c
@@ -490,6 +490,9 @@ mon_arrive(struct monst *mtmp, int when)
         if (t) {
             xlocale = t->tx, ylocale = t->ty;
             break;
+        } else if (iflags.debug_fuzzer && (stway = stairway_find_dir(TRUE)) != 0) {
+            /* debugfuzzer returning from knox */
+            xlocale = stway->sx, ylocale = stway->sy;
         } else if (!(u.uevent.qexpelled
                      && (Is_qstart(&u.uz0) || Is_qstart(&u.uz)))) {
             impossible("mon_arrive: no corresponding portal?");
diff --git a/src/mklev.c b/src/mklev.c
index 5efa37dbb..99a9f90d0 100644
--- a/src/mklev.c
+++ b/src/mklev.c
@@ -1313,7 +1313,10 @@ place_branch(
     }
 
     if (br->type == BR_PORTAL) {
-        mkportal(x, y, dest->dnum, dest->dlevel);
+        if (u.ucamefrom.dnum || u.ucamefrom.dlevel)
+            mkportal(x, y, u.ucamefrom.dnum, u.ucamefrom.dlevel);
+        else
+            mkportal(x, y, dest->dnum, dest->dlevel);
     } else if (make_stairs) {
         boolean goes_up = on_level(&br->end1, &u.uz) ? br->end1_up
                                                      : !br->end1_up;
diff --git a/src/teleport.c b/src/teleport.c
index 1eef5a146..884ee82ff 100644
--- a/src/teleport.c
+++ b/src/teleport.c
@@ -866,6 +866,7 @@ level_tele(void)
                  || gd.dungeons[newlevel.dnum].flags.unconnected
                  || !gd.dungeons[newlevel.dnum].num_dunlevs);
         newlevel.dlevel = 1 + rn2(dunlevs_in_dungeon(&newlevel));
+        assign_level(&u.ucamefrom, &u.uz);
         schedule_goto(&newlevel, UTOTYPE_NONE, (char *) 0, (char *) 0);
         return;
     }