fix #Q431 - water elemental caught in beartrap (trunk only)

Reported two months ago by <email deleted>,
having a water elemental become trapped in a bear trap seems pretty
strange.  Fixed by marking water elementals as M1_UNSOLID (like air and
fire elementals), which has a side-effect of making them immune to webs
as well.  Tweaked some unused digging code which checks unsolid(), added
unsolid() to the types allowed to bar through iron bars, and brought the
check for whether a monster is willing to enter a bear trap location up
to date.  That code also needed an update to reflect the change made to
anti-magic traps last year.  Lastly, there was another report which
suggested that being hit by a bear trap should dish out some damage
(along with a suggestion that wand of opening should work to escape such
traps, which has already been done).  This makes bear trap do 2d4 damage
(on entry, not when trying to pull out after becoming stuck).

doc/fixes35.0

@@ -210,6 +210,8 @@ unicorn horn produced by revived monster will polymorph as if non-magic
 stone-to-flesh on any golem statue or golem figurine creates flesh golem
 stone-to-flesh which activates shop-owned figurine entails shop charges
 make giants be less likely to be randomly generated in Sokoban
+bear traps dish out some damage on initial entrapment
+bear traps and webs are harmless to water elementals
 
 
 Platform- and/or Interface-Specific Fixes

src/dig.c

@@ -1,4 +1,4 @@
-/*	SCCS Id: @(#)dig.c	3.5	2006/07/08	*/
+/*	SCCS Id: @(#)dig.c	3.5	2007/04/02	*/
 /* Copyright (c) Stichting Mathematisch Centrum, Amsterdam, 1985. */
 /* NetHack may be freely redistributed.  See license for details. */
 
@@ -1937,7 +1937,9 @@ escape_tomb()
 		boolean good;
 
 		if(amorphous(youmonst.data) || Passes_walls ||
-		   noncorporeal(youmonst.data) || unsolid(youmonst.data) ||
+		   noncorporeal(youmonst.data) ||
+		   (unsolid(youmonst.data) &&
+			youmonst.data != &mons[PM_WATER_ELEMENTAL]) ||
 		   (tunnels(youmonst.data) && !needspick(youmonst.data))) {
 
 		    You("%s up through the %s.",

src/mon.c

@@ -1192,12 +1192,15 @@ impossible("A monster looked at a very strange trap of type %d.", ttmp->ttyp);
 				    !resists_sleep(mon))
 				&& (ttmp->ttyp != BEAR_TRAP ||
 				    (mdat->msize > MZ_SMALL &&
-				     !amorphous(mdat) && !is_flyer(mdat)))
+				     !amorphous(mdat) && !is_flyer(mdat) &&
+				     !is_whirly(mdat) && !unsolid(mdat)))
 				&& (ttmp->ttyp != FIRE_TRAP ||
 				    !resists_fire(mon))
 				&& (ttmp->ttyp != SQKY_BOARD || !is_flyer(mdat))
 				&& (ttmp->ttyp != WEB || (!amorphous(mdat) &&
 				    !webmaker(mdat)))
+				&& (ttmp->ttyp != ANTI_MAGIC ||
+				    !resists_magm(mon))
 			) {
 			    if (!(flag & ALLOW_TRAPS)) {
 				if (mon->mtrapseen & (1L << (ttmp->ttyp - 1)))

src/mondata.c

@@ -283,7 +283,7 @@ passes_bars(mptr)
 struct permonst *mptr;
 {
     return (boolean) (passes_walls(mptr) || amorphous(mptr) ||
-		      is_whirly(mptr) || verysmall(mptr) ||
+		      unsolid(mptr) || is_whirly(mptr) || verysmall(mptr) ||
 		      (slithy(mptr) && !bigmonst(mptr)));
 }
 

src/monst.c

@@ -1,4 +1,4 @@
-/*	SCCS Id: @(#)monst.c	3.5	2006/02/13	*/
+/*	SCCS Id: @(#)monst.c	3.5	2007/04/02	*/
 /* Copyright (c) Stichting Mathematisch Centrum, Amsterdam, 1985. */
 /* NetHack may be freely redistributed.  See license for details. */
 
@@ -1389,7 +1389,8 @@ NEARDATA struct permonst mons[] = {
 	A(ATTK(AT_CLAW, AD_PHYS, 5, 6),
 	  NO_ATTK, NO_ATTK, NO_ATTK, NO_ATTK, NO_ATTK),
 	SIZ(2500, 0, MS_SILENT, MZ_HUGE), MR_POISON|MR_STONE, 0,
-	M1_NOEYES|M1_NOLIMBS|M1_NOHEAD|M1_MINDLESS|M1_AMPHIBIOUS|M1_SWIM,
+	M1_NOEYES|M1_NOLIMBS|M1_NOHEAD|M1_MINDLESS|M1_UNSOLID|
+	  M1_AMPHIBIOUS|M1_SWIM,
 	M2_STRONG|M2_NEUTER, 0, CLR_BLUE),
 /*
  * Fungi

src/trap.c

@@ -852,6 +852,9 @@ unsigned trflags;
 		break;
 
 	    case BEAR_TRAP:
+	    {
+		int dmg = d(2, 4);
+
 		if ((Levitation || Flying) && !forcetrap) break;
 		feeltrap(trap);
 		if(amorphous(youmonst.data) || is_whirly(youmonst.data) ||
@@ -876,6 +879,8 @@ unsigned trflags;
 		    pline("%s bear trap closes on %s %s!",
 			A_Your[trap->madeby_u], s_suffix(mon_nam(u.usteed)),
 			mbodypart(u.usteed, FOOT));
+		    if (thitm(0, u.usteed, (struct obj *)0, dmg, FALSE))
+			u.utrap = 0;	/* steed died, hero not trapped */
 		} else
 #endif
 		{
@@ -883,9 +888,11 @@ unsigned trflags;
 			    A_Your[trap->madeby_u], body_part(FOOT));
 		    if(u.umonnum == PM_OWLBEAR || u.umonnum == PM_BUGBEAR)
 			You("howl in anger!");
+		    losehp(Maybe_Half_Phys(dmg), "bear trap", KILLED_BY_AN);
 		}
 		exercise(A_DEX, FALSE);
 		break;
+	    }
 
 	    case SLP_GAS_TRAP:
 		seetrap(trap);
@@ -2055,6 +2062,9 @@ register struct monst *mtmp;
 				seetrap(trap);
 			    }
 			}
+			if (mtmp->mtrapped)
+			    trapkilled = thitm(0, mtmp, (struct obj *)0,
+					       d(2, 4), FALSE);
 			break;
 
 		case SLP_GAS_TRAP:
@@ -2365,8 +2375,9 @@ glovecheck:		    target = which_armor(mtmp, W_ARMG);
 		case ANTI_MAGIC:
 			/* similar to hero's case, more or less */
 			if (!resists_magm(mtmp)) {	/* lose spell energy */
-			    if (attacktype(mptr, AT_MAGC) ||
+			    if (!mtmp->mcan &&
-				    attacktype(mptr, AT_BREA)) {
+				    (attacktype(mptr, AT_MAGC) ||
+				     attacktype(mptr, AT_BREA))) {
 				mtmp->mspec_used += d(2, 2);
 				if (in_sight) {
 				    seetrap(trap);