From a bug report: monsters hit by polymorph

magic while wearing dragon scales/scale mail were being turned
into random monsters instead of into dragons.

Also

Two items from <Someone>'s list.

Files patched:
  include/obj.h
  src/mon.c, muse.c, worn.c, zap.c

src/mon.c

@@ -1,4 +1,4 @@
-/*	SCCS Id: @(#)mon.c	3.3	2001/09/06	*/
+/*	SCCS Id: @(#)mon.c	3.3	2002/01/07	*/
 /* Copyright (c) Stichting Mathematisch Centrum, Amsterdam, 1985. */
 /* NetHack may be freely redistributed.  See license for details. */
 
@@ -2153,6 +2153,14 @@ struct monst *mon;
 		if (!rn2(3)) mndx = pick_animal();
 		break;
 	    case CHAM_ORDINARY:
+	      {
+		struct obj *m_armr = which_armor(mon, W_ARM);
+
+		if (m_armr && Is_dragon_scales(m_armr))
+		    mndx = Dragon_scales_to_pm(m_armr) - mons;
+		else if (m_armr && Is_dragon_mail(m_armr))
+		    mndx = Dragon_mail_to_pm(m_armr) - mons;
+	      }
 		break;
 	}
 #ifdef WIZARD

src/muse.c

@@ -1,4 +1,4 @@
-/*	SCCS Id: @(#)muse.c	3.3	2001/11/19	*/
+/*	SCCS Id: @(#)muse.c	3.3	2002/01/07	*/
 /*	Copyright (C) 1990 by Ken Arromdee			   */
 /* NetHack may be freely redistributed.  See license for details.  */
 
@@ -19,6 +19,7 @@ boolean m_using = FALSE;
  * don't know not to read scrolls, etc....
  */
 
+STATIC_DCL struct permonst *FDECL(muse_newcham_mon, (struct monst *));
 STATIC_DCL int FDECL(precheck, (struct monst *,struct obj *));
 STATIC_DCL void FDECL(mzapmsg, (struct monst *,struct obj *,BOOLEAN_P));
 STATIC_DCL void FDECL(mreadmsg, (struct monst *,struct obj *));
@@ -1637,6 +1638,23 @@ struct monst *mtmp;
 #undef nomore
 }
 
+/* type of monster to polymorph into; defaults to one suitable for the
+   current level rather than the totally arbitrary choice of newcham() */
+static struct permonst *
+muse_newcham_mon(mon)
+struct monst *mon;
+{
+	struct obj *m_armr;
+
+	if ((m_armr = which_armor(mon, W_ARM)) != 0) {
+	    if (Is_dragon_scales(m_armr))
+		return Dragon_scales_to_pm(m_armr);
+	    else if (Is_dragon_mail(m_armr))
+		return Dragon_mail_to_pm(m_armr);
+	}
+	return rndmonst();
+}
+
 int
 use_misc(mtmp)
 struct monst *mtmp;
@@ -1735,13 +1753,13 @@ skipmsg:
 	case MUSE_WAN_POLYMORPH:
 		mzapmsg(mtmp, otmp, TRUE);
 		otmp->spe--;
-		(void) newcham(mtmp, rndmonst(), TRUE);
+		(void) newcham(mtmp, muse_newcham_mon(mtmp), TRUE);
 		if (oseen) makeknown(WAN_POLYMORPH);
 		return 2;
 	case MUSE_POT_POLYMORPH:
 		mquaffmsg(mtmp, otmp);
 		if (vismon) pline("%s suddenly mutates!", Monnam(mtmp));
-		(void) newcham(mtmp, rndmonst(), FALSE);
+		(void) newcham(mtmp, muse_newcham_mon(mtmp), FALSE);
 		if (oseen) makeknown(POT_POLYMORPH);
 		m_useup(mtmp, otmp);
 		return 2;
@@ -1999,7 +2017,8 @@ const char *str;
 	    if (str)
 		pline(str, s_suffix(mon_nam(mon)), "armor");
 	    return TRUE;
-	} else if (mon->data == &mons[PM_SILVER_DRAGON]) {
+	} else if (mon->data == &mons[PM_SILVER_DRAGON] ||
+		mon->data == &mons[PM_CHROMATIC_DRAGON]) {
 	    /* Silver dragons only reflect when mature; babies do not */
 	    if (str)
 		pline(str, s_suffix(mon_nam(mon)), "scales");

src/worn.c

@@ -1,4 +1,4 @@
-/*	SCCS Id: @(#)worn.c	3.3	2001/09/05	*/
+/*	SCCS Id: @(#)worn.c	3.3	2002/01/07	*/
 /* Copyright (c) Stichting Mathematisch Centrum, Amsterdam, 1985. */
 /* NetHack may be freely redistributed.  See license for details. */
 
@@ -530,7 +530,13 @@ boolean polyspot;
 
 	if (breakarm(mdat)) {
 	    if ((otmp = which_armor(mon, W_ARM)) != 0) {
-		if (vis)
+		if ((Is_dragon_scales(otmp) &&
+			mdat == Dragon_scales_to_pm(otmp)) ||
+		    (Is_dragon_mail(otmp) && mdat == Dragon_mail_to_pm(otmp)))
+		    ;	/* no message here;
+			   "the dragon merges with his scaly armor" is odd
+			   and the monster's previous form is already gone */
+		else if (vis)
 		    pline("%s breaks out of %s armor!", Monnam(mon), ppronoun);
 		else
 		    You_hear("a cracking sound.");

src/zap.c

@@ -1,4 +1,4 @@
-/*	SCCS Id: @(#)zap.c	3.3	2001/12/29	*/
+/*	SCCS Id: @(#)zap.c	3.3	2002/01/07	*/
 /* Copyright (c) Stichting Mathematisch Centrum, Amsterdam, 1985. */
 /* NetHack may be freely redistributed.  See license for details. */
 
@@ -178,7 +178,10 @@ struct obj *otmp;
 		       it guard against involuntary polymorph attacks too... */
 		    shieldeff(mtmp->mx, mtmp->my);
 		} else if (!resist(mtmp, otmp->oclass, 0, NOTELL)) {
-		    if (!rn2(25)) {
+		    /* natural shapechangers aren't affected by system shock
+		       (unless protection from shapechangers is interfering
+		       with their metabolism...) */
+		    if (mtmp->cham == CHAM_ORDINARY && !rn2(25)) {
 			if (canseemon(mtmp)) {
 			    pline("%s shudders!", Monnam(mtmp));
 			    makeknown(otyp);
@@ -4029,9 +4032,14 @@ retry:
 	u.uconduct.wishes++;
 
 	if (otmp != &zeroobj) {
-	    if(otmp->oartifact && !touch_artifact(otmp,&youmonst))
-		dropy(otmp);
-	    else
+	    /* in case touching this object turns out to be fatal */
+	    place_object(otmp, u.ux, u.uy);
+
+	    if (otmp->oartifact && !touch_artifact(otmp,&youmonst)) {
+		obj_extract_self(otmp);	/* remove it from the floor */
+		dropy(otmp);		/* now put it back again :-) */
+	    } else {
+		obj_extract_self(otmp);
 		/* The(aobjnam()) is safe since otmp is unidentified -dlc */
 		(void) hold_another_object(otmp, u.uswallow ?
 				       "Oops!  %s out of your reach!" :
@@ -4042,6 +4050,7 @@ retry:
 					     Is_airlevel(&u.uz) || u.uinwater ?
 						   "slip" : "drop")),
 				       (const char *)0);
+	    }
 	    u.ublesscnt += rn1(100,50);  /* the gods take notice */
 	}
 }