From fee66f29059e1297522fb25aa5a0b76c2e14c003 Mon Sep 17 00:00:00 2001
From: nhmall <nhmall@nethack.org>
Date: Thu, 15 Jun 2023 09:29:41 -0400
Subject: [PATCH] don't hide under statues, statue trap or not

Unlike ground clutter, statues are typically in pretty tight contact
with the ground; statue traps are sometimes proclaimed as "monsters
posing as statues".
---
 include/extern.h |  1 +
 src/mon.c        | 10 ++++++----
 src/monmove.c    | 18 +++++++++++++++++-
 3 files changed, 24 insertions(+), 5 deletions(-)

diff --git a/include/extern.h b/include/extern.h
index 9cbc33bf2..6104ef938 100644
--- a/include/extern.h
+++ b/include/extern.h
@@ -1730,6 +1730,7 @@ extern boolean can_fog(struct monst *);
 extern boolean should_displace(struct monst *, coord *, long *, int, coordxy,
                                coordxy);
 extern boolean undesirable_disp(struct monst *, coordxy, coordxy);
+extern boolean can_hide_under_obj(struct obj *);
 
 /* ### monst.c ### */
 
diff --git a/src/mon.c b/src/mon.c
index 2039f59e4..9cc190b62 100644
--- a/src/mon.c
+++ b/src/mon.c
@@ -4196,7 +4196,9 @@ maybe_unhide_at(coordxy x, coordxy y)
     }
 
     if (undetected
-        && ((hides_under(mtmp->data) && (!OBJ_AT(x, y) || trapped))
+        && ((hides_under(mtmp->data)
+             && (!OBJ_AT(x, y) || trapped
+                 || !can_hide_under_obj(gl.level.objects[x][y])))
             || (mtmp->data->mlet == S_EEL && !is_pool(x, y))))
         (void) hideunder(mtmp);
 }
@@ -4210,6 +4212,7 @@ hideunder(struct monst *mtmp)
     int seeit = canseemon(mtmp);
     boolean oldundetctd, undetected = FALSE, is_u = (mtmp == &gy.youmonst);
     coordxy x = is_u ? u.ux : mtmp->mx, y = is_u ? u.uy : mtmp->my;
+    struct obj *otmp;
 
     if (mtmp == u.ustuck) {
         ; /* undetected==FALSE; can't hide if holding you or held by you */
@@ -4221,9 +4224,8 @@ hideunder(struct monst *mtmp)
         undetected = (is_pool(x, y) && !Is_waterlevel(&u.uz));
         if (seeit)
             seenobj = "the water";
-    } else if (hides_under(mtmp->data) && OBJ_AT(x, y)) {
-        struct obj *otmp = gl.level.objects[x][y];
-
+    } else if (hides_under(mtmp->data) && OBJ_AT(x, y)
+        && (otmp = gl.level.objects[x][y]) != 0 && can_hide_under_obj(otmp)) {
         if (seeit)
             seenobj = ansimpleoname(otmp);
         /* most monsters won't hide under cockatrice corpse but they
diff --git a/src/monmove.c b/src/monmove.c
index 547260bdd..369feb279 100644
--- a/src/monmove.c
+++ b/src/monmove.c
@@ -1312,7 +1312,8 @@ m_move(register struct monst *mtmp, int after)
             finish_meating(mtmp);
         return MMOVE_DONE; /* still eating */
     }
-    if (hides_under(ptr) && OBJ_AT(mtmp->mx, mtmp->my) && rn2(10))
+    if (hides_under(ptr) && OBJ_AT(mtmp->mx, mtmp->my)
+        && can_hide_under_obj(gl.level.objects[mtmp->mx][mtmp->my]) && rn2(10))
         return MMOVE_NOTHING; /* do not leave hiding place */
 
     /* Where does 'mtmp' think you are?  Not necessary if m_move() called
@@ -1893,6 +1894,21 @@ m_move_aggress(struct monst *mtmp, coordxy x, coordxy y)
     return MMOVE_DONE;
 }
 
+/* returns TRUE if a mon can hide under the obj */
+boolean
+can_hide_under_obj(struct obj *obj)
+{
+    struct trap *t;
+
+    if (!obj || (obj->otyp == STATUE
+          /* uncomment this next line for just statue traps */
+          /* && (t = t_at(obj->ox, obj->oy)) != 0 && t->ttyp == STATUE_TRAP */
+        ))
+        return FALSE;
+   return TRUE;
+   nhUse(t);
+}
+
 void
 dissolve_bars(coordxy x, coordxy y)
 {