migrating monster fix

The change to zero out a monster's map coordinates when it is taken
off the map yesterday messed up migration between levels inside the
Wizard's tower.  (Didn't apply when accompanying the hero between
levels, so probably unlikely to be noticed.)

Noticed while moving some replicated code into its own routine.

diff --git a/src/dog.c b/src/dog.c
index 8658582ad44653ab9c9b17c9a9e6018be3d121bd..965b21741506d02711d27d19dcf04ce0e51e560f 100644 (file)
--- a/src/dog.c
+++ b/src/dog.c
@@ -1,4 +1,4 @@
-/* NetHack 3.7 dog.c   $NHDT-Date: 1652478351 2022/05/13 21:45:51 $  $NHDT-Branch: NetHack-3.7 $:$NHDT-Revision: 1.118 $ */
+/* NetHack 3.7 dog.c   $NHDT-Date: 1652524227 2022/05/14 10:30:27 $  $NHDT-Branch: NetHack-3.7 $:$NHDT-Revision: 1.119 $ */
 /* Copyright (c) Stichting Mathematisch Centrum, Amsterdam, 1985. */
 /*-Copyright (c) Robert Patrick Rankin, 2011. */
 /* NetHack may be freely redistributed.  See license for details. */
@@ -7,6 +7,7 @@
 
 static int pet_type(void);
 static void set_mon_lastmove(struct monst *);
+static int mon_leave(struct monst *);
 
 void
 newedog(struct monst *mtmp)
@@ -578,14 +579,50 @@ mon_catchup_elapsed_time(
         mtmp->mhp += imv;
 }
 
+/* bookkeeping when mtmp is about to leave the current level;
+   common to keepdogs() and migrate_to_level() */
+static int
+mon_leave(struct monst *mtmp)
+{
+    struct obj *obj;
+    int num_segs = 0; /* return value */
+
+    /* set minvent's obj->no_charge to 0 */
+    for (obj = mtmp->minvent; obj; obj = obj->nobj) {
+        if (Has_contents(obj))
+            picked_container(obj); /* does the right thing */
+        obj->no_charge = 0;
+    }
+
+    /* if this is a shopkeeper, clear the 'resident' field of her shop;
+       if/when she returns, it will be set back by mon_arrive()  */
+    if (mtmp->isshk)
+        set_residency(mtmp, TRUE);
+
+    /* if this is a long worm, handle its tail segments before mtmp itself;
+       we pass possibly trundated segment count to caller via return value  */
+    if (mtmp->wormno) {
+        int cnt = count_wsegs(mtmp);
+
+        /* since monst->wormno is overloaded to hold the number of
+           tail segments during migration, a very long worm with
+           more segments than can fit in that field gets truncated */
+        num_segs = min(cnt, MAX_NUM_WORMS - 1);
+        wormgone(mtmp); /* discard tail segments, take head off map */
+        /* this used to be place_monster() but relmon() doesn't
+           need that as long as coordinates reflect actual state */
+        mtmp->mx = mtmp->my = 0; /* off normal map */
+    }
+
+    return num_segs;
+}
+
 /* called when you move to another level */
 void
-keepdogs(boolean pets_only) /* true for ascension or final escape */
+keepdogs(
+    boolean pets_only) /* true for ascension or final escape */
 {
     register struct monst *mtmp, *mtmp2;
-    register struct obj *obj;
-    int num_segs;
-    boolean stay_behind;
 
     for (mtmp = fmon; mtmp; mtmp = mtmp2) {
         mtmp2 = mtmp->nmon;
@@ -615,7 +652,9 @@ keepdogs(boolean pets_only) /* true for ascension or final escape */
                 || (mtmp == u.usteed))
             /* monster won't follow if it hasn't noticed you yet */
             && !(mtmp->mstrategy & STRAT_WAITFORU)) {
-            stay_behind = FALSE;
+            int num_segs;
+            boolean stay_behind = FALSE;
+
             if (mtmp->mtrapped)
                 (void) mintrap(mtmp, NO_TRAP_FLAGS); /* try to escape */
             if (mtmp == u.usteed) {
@@ -650,30 +689,9 @@ keepdogs(boolean pets_only) /* true for ascension or final escape */
                 }
                 continue;
             }
-            if (mtmp->isshk)
-                set_residency(mtmp, TRUE);
-
-            /* set minvent's obj->no_charge to 0 */
-            for (obj = mtmp->minvent; obj; obj = obj->nobj) {
-                if (Has_contents(obj))
-                    picked_container(obj); /* does the right thing */
-                obj->no_charge = 0;
-            }
-
-            if (mtmp->wormno) {
-                int cnt = count_wsegs(mtmp);
-
-                /* since monst->wormno is overloaded to hold the number of
-                   tail segments during migration, a very long worm with
-                   more segments than can fit in that field gets truncated */
-                num_segs = min(cnt, MAX_NUM_WORMS - 1);
-                wormgone(mtmp); /* discard tail segments, take head off map */
-                /* this used to be place_monster() but relmon() doesn't
-                   need that as long as coordinates reflect actual state */
-                mtmp->mx = mtmp->my = 0; /* off normal map */
-            } else
-                num_segs = 0;
 
+            /* prepare to take mtmp off the map */
+            num_segs = mon_leave(mtmp);
             /* take off map and move mtmp from fmon list to mydogs */
             relmon(mtmp, &g.mydogs); /* mtmp->mx,my get changed to 0,0 */
             mtmp->wormno = num_segs;
@@ -700,31 +718,12 @@ migrate_to_level(
     xchar xyloc, /* MIGR_xxx destination xy location: */
     coord *cc)   /* optional destination coordinates */
 {
-    struct obj *obj;
     d_level new_lev;
-    xchar xyflags, mx = mtmp->mx, my = mtmp->my; /* might be needed below */
-    int num_segs = 0; /* count of worm segments */
-
-    if (mtmp->isshk)
-        set_residency(mtmp, TRUE);
-
-    if (mtmp->wormno) {
-        int cnt = count_wsegs(mtmp);
+    xchar xyflags, mx = mtmp->mx, my = mtmp->my; /* <mx,my> needed below */
+    int num_segs; /* count of worm segments */
 
-        /* **** NOTE: worm is truncated to # segs = max wormno size **** */
-        num_segs = min(cnt, MAX_NUM_WORMS - 1); /* used below */
-        wormgone(mtmp); /* destroys tail and takes head off map */
-        /* there used to be a place_monster() here for the relmon() below,
-           but it doesn't require the monster to be on the map anymore */
-        mtmp->mx = mtmp->my = 0; /* wormgone() doesn't do this for us */
-    }
-
-    /* set minvent's obj->no_charge to 0 */
-    for (obj = mtmp->minvent; obj; obj = obj->nobj) {
-        if (Has_contents(obj))
-            picked_container(obj); /* does the right thing */
-        obj->no_charge = 0;
-    }
+    /* prepare to take mtmp off the map */
+    num_segs = mon_leave(mtmp);
 
     if (mtmp->mleashed) {
         mtmp->mtame--;
@@ -737,10 +736,10 @@ migrate_to_level(
 
     new_lev.dnum = ledger_to_dnum((xchar) tolev);
     new_lev.dlevel = ledger_to_dlev((xchar) tolev);
-    /* overload mtmp->[mx,my], mtmp->[mux,muy], and mtmp->mtrack[] as */
-    /* destination codes (setup flag bits before altering mx or my) */
+    /* overload mtmp->[mx,my], mtmp->[mux,muy], and mtmp->mtrack[] as
+       destination codes */
     xyflags = (depth(&new_lev) < depth(&u.uz)); /* 1 => up */
-    if (In_W_tower(mtmp->mx, mtmp->my, &u.uz))
+    if (In_W_tower(mx, my, &u.uz))
         xyflags |= 2;
     mtmp->wormno = num_segs;
     mtmp->mlstmv = g.moves;