diff --git a/include/extern.h b/include/extern.h
index d85e8f881..f0e6a0adb 100644
--- a/include/extern.h
+++ b/include/extern.h
@@ -1,4 +1,4 @@
-/* NetHack 3.7	extern.h	$NHDT-Date: 1693359531 2023/08/30 01:38:51 $  $NHDT-Branch: keni-crashweb2 $:$NHDT-Revision: 1.1281 $ */
+/* NetHack 3.7	extern.h	$NHDT-Date: 1695159584 2023/09/19 21:39:44 $  $NHDT-Branch: NetHack-3.7 $:$NHDT-Revision: 1.1287 $ */
 /* Copyright (c) Steve Creps, 1988.                               */
 /* NetHack may be freely redistributed.  See license for details. */
 
@@ -1148,6 +1148,7 @@ extern void addinv_core1(struct obj *);
 extern void addinv_core2(struct obj *);
 extern struct obj *addinv(struct obj *);
 extern struct obj *addinv_before(struct obj *, struct obj *);
+extern struct obj *addinv_nomerge(struct obj *);
 extern struct obj *hold_another_object(struct obj *, const char *,
                                        const char *, const char *);
 extern void useupall(struct obj *);
diff --git a/src/apply.c b/src/apply.c
index 579f9833c..deb21a967 100644
--- a/src/apply.c
+++ b/src/apply.c
@@ -1,4 +1,4 @@
-/* NetHack 3.7	apply.c	$NHDT-Date: 1685202442 2023/05/27 15:47:22 $  $NHDT-Branch: NetHack-3.7 $:$NHDT-Revision: 1.420 $ */
+/* NetHack 3.7	apply.c	$NHDT-Date: 1695159606 2023/09/19 21:40:06 $  $NHDT-Branch: NetHack-3.7 $:$NHDT-Revision: 1.422 $ */
 /* Copyright (c) Stichting Mathematisch Centrum, Amsterdam, 1985. */
 /*-Copyright (c) Robert Patrick Rankin, 2012. */
 /* NetHack may be freely redistributed.  See license for details. */
@@ -3499,9 +3499,7 @@ use_royal_jelly(struct obj **optr)
             update_inventory(); /* freeinv() updated perminv w/ obj omitted */
         } else {
             /* this lump was already separate; pervent merge */
-            obj->nomerge = 1;
-            addinv(obj); /* put the unused lump back; updates perminv */
-            obj->nomerge = 0;
+            addinv_nomerge(obj); /* put unused lump back; updates perminv */
         }
         return ECMD_CANCEL;
     }
diff --git a/src/dothrow.c b/src/dothrow.c
index 83faea149..36885835d 100644
--- a/src/dothrow.c
+++ b/src/dothrow.c
@@ -1,4 +1,4 @@
-/* NetHack 3.7	dothrow.c	$NHDT-Date: 1683334246 2023/05/06 00:50:46 $  $NHDT-Branch: NetHack-3.7 $:$NHDT-Revision: 1.266 $ */
+/* NetHack 3.7	dothrow.c	$NHDT-Date: 1695159620 2023/09/19 21:40:20 $  $NHDT-Branch: NetHack-3.7 $:$NHDT-Revision: 1.269 $ */
 /* Copyright (c) Stichting Mathematisch Centrum, Amsterdam, 1985. */
 /*-Copyright (c) Robert Patrick Rankin, 2013. */
 /* NetHack may be freely redistributed.  See license for details. */
@@ -1834,9 +1834,9 @@ return_throw_to_inv(
     /* if 'obj' wasn't from a stack split or if it wouldn't merge back
        (maybe new erosion damage?) then it needs to be added to invent;
        don't merge with any other stack even if there is a compatible one
-       (others with similar erosion?) */
+       (others with similar erosion?); can't use addinv_nomerge() here */
     if (!otmp) {
-        obj->nomerge = 1;
+        obj->nomerge = 1; /* redundant unless 'oldslot' somehow went away */
         obj = addinv_before(obj, oldslot);
         obj->nomerge = 0;
 
diff --git a/src/eat.c b/src/eat.c
index a2a050619..edff2221b 100644
--- a/src/eat.c
+++ b/src/eat.c
@@ -1,4 +1,4 @@
-/* NetHack 3.7	eat.c	$NHDT-Date: 1674294705 2023/01/21 09:51:45 $  $NHDT-Branch: NetHack-3.7 $:$NHDT-Revision: 1.301 $ */
+/* NetHack 3.7	eat.c	$NHDT-Date: 1695159623 2023/09/19 21:40:23 $  $NHDT-Branch: NetHack-3.7 $:$NHDT-Revision: 1.310 $ */
 /* Copyright (c) Stichting Mathematisch Centrum, Amsterdam, 1985. */
 /*-Copyright (c) Robert Patrick Rankin, 2012. */
 /* NetHack may be freely redistributed.  See license for details. */
@@ -367,9 +367,7 @@ touchfood(struct obj *otmp)
             dropy(otmp);
             sellobj_state(SELL_NORMAL);
         } else {
-            otmp->nomerge = 1; /* used to prevent merge */
-            otmp = addinv(otmp);
-            otmp->nomerge = 0;
+            otmp = addinv_nomerge(otmp);
         }
     }
     return otmp;
diff --git a/src/invent.c b/src/invent.c
index 0998438ac..f91026545 100644
--- a/src/invent.c
+++ b/src/invent.c
@@ -1,4 +1,4 @@
-/* NetHack 3.7	invent.c	$NHDT-Date: 1672827802 2023/01/04 10:23:22 $  $NHDT-Branch: naming-overflow-fix $:$NHDT-Revision: 1.439 $ */
+/* NetHack 3.7	invent.c	$NHDT-Date: 1695159625 2023/09/19 21:40:25 $  $NHDT-Branch: NetHack-3.7 $:$NHDT-Revision: 1.449 $ */
 /* Copyright (c) Stichting Mathematisch Centrum, Amsterdam, 1985. */
 /*-Copyright (c) Derek S. Ray, 2015. */
 /* NetHack may be freely redistributed.  See license for details. */
@@ -860,11 +860,11 @@ addinv_core1(struct obj *obj)
     if (is_mines_prize(obj)) {
         record_achievement(ACH_MINE_PRIZE);
         gc.context.achieveo.mines_prize_oid = 0; /* done with luckstone o_id */
-        obj->nomerge = 0;
+        obj->nomerge = 0; /* was set in create_object(sp_lev.c) */
     } else if (is_soko_prize(obj)) {
         record_achievement(ACH_SOKO_PRIZE);
         gc.context.achieveo.soko_prize_oid = 0; /* done with bag/amulet o_id */
-        obj->nomerge = 0;
+        obj->nomerge = 0; /* (got set in sp_lev.c) */
     }
 }
 
@@ -914,7 +914,7 @@ addinv_core0(struct obj *obj, struct obj *other_obj,
         reset_justpicked(gi.invent);
     }
 
-    addinv_core1(obj);
+    addinv_core1(obj); /* handle most side effects of carrying obj */
 
     /* for addinv_before(); if something has been removed and is now being
        reinserted, try to put it in the same place instead of merging or
@@ -975,7 +975,7 @@ addinv_core0(struct obj *obj, struct obj *other_obj,
         setuqwep(obj);
  added:
     obj->pickup_prev = 1;
-    addinv_core2(obj);
+    addinv_core2(obj); /* handle extrinsics conferred by carrying obj */
     carry_obj_effects(obj); /* carrying affects the obj */
     if (update_perm_invent)
         update_inventory();
@@ -989,13 +989,28 @@ addinv(struct obj *obj)
     return addinv_core0(obj, (struct obj *) 0, TRUE);
 }
 
-/* add obj to the hero's inventory by inserting in front of a specific item */
+/* add obj to the hero's inventory by inserting in front of a specific item;
+   used for throw-and-return in case '!fixinv' is in effect */
 struct obj *
 addinv_before(struct obj *obj, struct obj *other_obj)
 {
+    /* if 'other_obj' is present this will implicitly be 'nomerge' */
     return addinv_core0(obj, other_obj, TRUE);
 }
 
+/* return value will always be 'obj' */
+struct obj *
+addinv_nomerge(struct obj *obj)
+{
+    struct obj *result;
+    unsigned save_nomerge = obj->nomerge;
+
+    obj->nomerge = 1;
+    result = addinv(obj);
+    obj->nomerge = save_nomerge;
+    return result;
+}
+
 /*
  * Some objects are affected by being carried.
  * Make those adjustments here. Called _after_ the object
@@ -1063,7 +1078,8 @@ hold_another_object(
     }
     if (Fumbling) {
         obj->nomerge = 1;
-        /* dropping expects obj to be in invent */
+        /* dropping expects obj to be in invent; since it's going to be
+           dropped, avoid perminv update when temporarily adding it */
         obj = addinv_core0(obj, (struct obj *) 0, FALSE);
         goto drop_it;
     } else {
diff --git a/src/nhlua.c b/src/nhlua.c
index df77c0ba0..5b644d172 100644
--- a/src/nhlua.c
+++ b/src/nhlua.c
@@ -1,4 +1,4 @@
-/* NetHack 3.7	nhlua.c	$NHDT-Date: 1673740532 2023/01/14 23:55:32 $  $NHDT-Branch: NetHack-3.7 $:$NHDT-Revision: 1.95 $ */
+/* NetHack 3.7	nhlua.c	$NHDT-Date: 1695159626 2023/09/19 21:40:26 $  $NHDT-Branch: NetHack-3.7 $:$NHDT-Revision: 1.115 $ */
 /*      Copyright (c) 2018 by Pasi Kallinen */
 /* NetHack may be freely redistributed.  See license for details. */
 
@@ -1583,9 +1583,7 @@ nhl_gamestate(lua_State *L)
             wornmask = otmp->owornmask;
             otmp->owornmask = 0L;
             extract_nobj(otmp, &gmst_invent);
-            otmp->nomerge = 1;
-            addinv(otmp);
-            otmp->nomerge = 0;
+            addinv_nomerge(otmp);
             if (wornmask)
                 setworn(otmp, wornmask);
         }
diff --git a/src/sp_lev.c b/src/sp_lev.c
index 2bd7419c8..80b8e96c6 100644
--- a/src/sp_lev.c
+++ b/src/sp_lev.c
@@ -1,4 +1,4 @@
-/* NetHack 3.7	sp_lev.c	$NHDT-Date: 1646428015 2022/03/04 21:06:55 $  $NHDT-Branch: NetHack-3.7 $:$NHDT-Revision: 1.259 $ */
+/* NetHack 3.7	sp_lev.c	$NHDT-Date: 1695159628 2023/09/19 21:40:28 $  $NHDT-Branch: NetHack-3.7 $:$NHDT-Revision: 1.339 $ */
 /*      Copyright (c) 1989 by Jean-Christophe Collet */
 /* NetHack may be freely redistributed.  See license for details. */
 
@@ -2349,7 +2349,8 @@ create_object(object *o, struct mkroom *croom)
             if (!gc.context.achieveo.mines_prize_oid) {
                 gc.context.achieveo.mines_prize_oid = otmp->o_id;
                 gc.context.achieveo.mines_prize_otyp = otmp->otyp;
-                /* prevent stacking; cleared when achievement is recorded */
+                /* prevent stacking; cleared when achievement is recorded;
+                   will be reset in addinv_core1() */
                 otmp->nomerge = 1;
             } else {
                 impossible(prize_warning, "mines end");
@@ -2358,7 +2359,8 @@ create_object(object *o, struct mkroom *croom)
             if (!gc.context.achieveo.soko_prize_oid) {
                 gc.context.achieveo.soko_prize_oid = otmp->o_id;
                 gc.context.achieveo.soko_prize_otyp = otmp->otyp;
-                otmp->nomerge = 1; /* redundant; Sokoban prizes don't stack */
+                otmp->nomerge = 1; /* redundant; Sokoban prizes don't stack;
+                                    * will be reset in addinv_core1() */
             } else {
                 impossible(prize_warning, "sokoban end");
             }
diff --git a/src/wield.c b/src/wield.c
index 456911adc..c32a11489 100644
--- a/src/wield.c
+++ b/src/wield.c
@@ -1,4 +1,4 @@
-/* NetHack 3.7	wield.c	$NHDT-Date: 1650875488 2022/04/25 08:31:28 $  $NHDT-Branch: NetHack-3.7 $:$NHDT-Revision: 1.90 $ */
+/* NetHack 3.7	wield.c	$NHDT-Date: 1695159631 2023/09/19 21:40:31 $  $NHDT-Branch: NetHack-3.7 $:$NHDT-Revision: 1.97 $ */
 /* Copyright (c) Stichting Mathematisch Centrum, Amsterdam, 1985. */
 /*-Copyright (c) Robert Patrick Rankin, 2009. */
 /* NetHack may be freely redistributed.  See license for details. */
@@ -430,9 +430,7 @@ dowield(void)
     if (finish_splitting) {
         /* wep was split off from something; give it its own invlet */
         freeinv(wep);
-        wep->nomerge = 1;
-        addinv(wep);
-        wep->nomerge = 0;
+        addinv_nomerge(wep);
     }
 
     /* Set your new primary weapon */
@@ -635,9 +633,7 @@ doquiver_core(const char *verb) /* "ready" or "fire" */
  quivering:
     if (finish_splitting) {
         freeinv(newquiver);
-        newquiver->nomerge = 1;
-        addinv(newquiver);
-        newquiver->nomerge = 0;
+        addinv_nomerge(newquiver);
     }
 
     if (!strcmp(verb, "ready")) {