From 49b43f760f5b85011577743530cf867cbc8e91ab Mon Sep 17 00:00:00 2001
From: copperwater <aosdict@gmail.com>
Date: Sat, 8 Mar 2025 07:47:28 -0500
Subject: [PATCH] Fix: a number of unblock_points shouldn't unblock
 unconditionally

Initially diagnosed in an xnethack fuzzer crash - unblock_point
shouldn't be called when a closed door becomes non-closed, because it's
possible that there's a gas cloud on the space which means it still
blocks vision. These always need to be recalc_block_point. A number of
them were fixed, but when I went through all the xnethack ones, I found
some that were unchanged from upstream NetHack. I reproduced the sanity
check impossibles usually by breathing gas at a door as an iron golem
and then opening or destroying the door to trigger the unblock_point
call.

The use of recalc_block_point in wizterrainwish was not triggering this
bug, but the previous code there basically duplicated
recalc_block_point.
---
 src/dig.c    | 2 +-
 src/dokick.c | 2 +-
 src/hack.c   | 2 +-
 src/music.c  | 2 +-
 src/objnam.c | 9 +--------
 src/trap.c   | 2 +-
 6 files changed, 6 insertions(+), 13 deletions(-)

diff --git a/src/dig.c b/src/dig.c
index 195222235..fabafac7b 100644
--- a/src/dig.c
+++ b/src/dig.c
@@ -1435,7 +1435,7 @@ mdig_tunnel(struct monst *mtmp)
         sawit = canseemon(mtmp); /* before door state change and unblock_pt */
         trapped = (here->doormask & D_TRAPPED) ? TRUE : FALSE;
         here->doormask = trapped ? D_NODOOR : D_BROKEN;
-        unblock_point(mtmp->mx, mtmp->my); /* vision */
+        recalc_block_point(mtmp->mx, mtmp->my); /* vision */
         newsym(mtmp->mx, mtmp->my);
         if (trapped) {
             seeit = canseemon(mtmp);
diff --git a/src/dokick.c b/src/dokick.c
index cf8bb405b..45d0b097c 100644
--- a/src/dokick.c
+++ b/src/dokick.c
@@ -949,7 +949,7 @@ kick_door(coordxy x, coordxy y, int avrg_attrib)
             gm.maploc->doormask = D_BROKEN;
         }
         feel_newsym(x, y); /* we know we broke it */
-        unblock_point(x, y); /* vision */
+        recalc_block_point(x, y); /* vision */
         if (shopdoor) {
             add_damage(x, y, SHOP_DOOR_COST);
             pay_for_damage("break", FALSE);
diff --git a/src/hack.c b/src/hack.c
index f28877e47..71d252af5 100644
--- a/src/hack.c
+++ b/src/hack.c
@@ -787,7 +787,7 @@ still_chewing(coordxy x, coordxy y)
         lev->typ = CORR;
     }
 
-    unblock_point(x, y); /* vision */
+    recalc_block_point(x, y); /* vision */
     newsym(x, y);
     if (digtxt)
         You1(digtxt); /* after newsym */
diff --git a/src/music.c b/src/music.c
index ca8c64f31..21614860d 100644
--- a/src/music.c
+++ b/src/music.c
@@ -463,7 +463,7 @@ do_earthquake(int force)
                 }
                 /* wasn't doorless, now it will be */
                 levl[x][y].doormask = D_NODOOR;
-                unblock_point(x, y);
+                recalc_block_point(x, y);
                 newsym(x, y); /* before pline */
                 if (cansee(x, y))
                     pline_The("door collapses.");
diff --git a/src/objnam.c b/src/objnam.c
index 4463a12bb..3a1cba698 100644
--- a/src/objnam.c
+++ b/src/objnam.c
@@ -3862,14 +3862,7 @@ wizterrainwish(struct _readobjnam_data *d)
         } else {
             if (u.utrap && u.utraptype == TT_LAVA && !is_lava(u.ux, u.uy))
                 reset_utrap(FALSE);
-
-            if (does_block(x, y, lev)) {
-                if (!didblock)
-                    block_point(x, y);
-            } else {
-                if (didblock)
-                    unblock_point(x, y);
-            }
+            recalc_block_point(x, y);
         }
 
         /* fixups for replaced terrain that aren't handled above */
diff --git a/src/trap.c b/src/trap.c
index f309dd595..934020cd1 100644
--- a/src/trap.c
+++ b/src/trap.c
@@ -3443,7 +3443,7 @@ launch_obj(
             }
             levl[x][y].doormask = D_BROKEN;
             if (dist)
-                unblock_point(x, y);
+                recalc_block_point(x, y);
         }
 
         /* if about to hit something, do so now */