Wizard of Yendor entering endgame

When entering the Plane of Earth (or level teleporting directly to
another endgame level in wizard mode), if the Wizard came off the
migrating_mons list instead being re-created from scratch, he would
be placed randomly on the level instead of next to the arrival point.
If his mstrategy field still had the STRAT_WAITFORU bit set and you
didn't move to where he could see you, he might never come after you,
at least until some future harassment event chose 'resurrect'.

src/dog.c

@@ -398,6 +398,9 @@ mon_arrive(struct monst *mtmp, int when)
         else
             mnexto(mtmp, RLOC_NOMSG);
         return;
+    } else if (when == Wiz_arrive) {
+        /* resurrect() is bringing existing wizard to harass the hero */
+        xyloc = MIGR_WITH_HERO;
     }
     /*
      * The monster arrived on this level independently of the player.
@@ -410,10 +413,9 @@ mon_arrive(struct monst *mtmp, int when)
         long nmv = g.moves - 1L - mtmp->mlstmv;
 
         mon_catchup_elapsed_time(mtmp, nmv);
-        mtmp->mlstmv = g.moves - 1L;
 
         /* let monster move a bit on new level (see placement code below) */
-        wander = (xint16) min(nmv, 8);
+        wander = (xint16) min(nmv, 8L);
     } else
         wander = 0;
 
@@ -526,7 +528,7 @@ mon_arrive(struct monst *mtmp, int when)
         if (when != Wiz_arrive)
             /* losedogs() will deal with this */
             relmon(mtmp, &failed_arrivals);
-        else
+        else /* when==Wiz_arrive => not being called by losedogs() */
             m_into_limbo(mtmp);
     }
 }
@@ -629,6 +631,8 @@ mon_catchup_elapsed_time(
         mtmp->mhp = mtmp->mhpmax;
     else
         mtmp->mhp += imv;
+
+    set_mon_lastmove(mtmp);
 }
 
 /* bookkeeping when mtmp is about to leave the current level;

src/teleport.c

@@ -1377,7 +1377,10 @@ rloc_to(struct monst *mtmp, coordxy x, coordxy y)
 }
 
 void
-rloc_to_flag(struct monst *mtmp, coordxy x, coordxy y, unsigned int rlocflags)
+rloc_to_flag(
+    struct monst *mtmp,
+    coordxy x, coordxy y,
+    unsigned rlocflags)
 {
     rloc_to_core(mtmp, x, y, rlocflags);
 }

src/wizard.c

@@ -709,6 +709,9 @@ resurrect(void)
                 if (!helpless(mtmp)) {
                     *mmtmp = mtmp->nmon;
                     mon_arrive(mtmp, -1); /* -1: Wiz_arrive (dog.c) */
+                    /* mx: mon_arrive() might have sent mtmp into limbo */
+                    if (!mtmp->mx)
+                        mtmp = 0;
                     /* note: there might be a second Wizard; if so,
                        he'll have to wait til the next resurrection */
                     break;
@@ -719,7 +722,16 @@ resurrect(void)
     }
 
     if (mtmp) {
-        mtmp->mtame = mtmp->mpeaceful = 0; /* paranoia */
+        /* if wizard ended up far away because of conjestion, clear his
+           wait-until-close flag; otherwise set that flag in case he just
+           came off the migrating_mons list to prevent him from triggering
+           "<mon> vanishes and reappears" on his first move */
+        if (!couldsee(mtmp->mx, mtmp->my))
+            mtmp->mstrategy &= ~STRAT_WAITMASK;
+        else
+            mtmp->mstrategy |= STRAT_WAITMASK;
+
+        mtmp->mtame = 0, mtmp->mpeaceful = 0; /* paranoia */
         set_malign(mtmp);
         if (!Deaf) {
             pline("A voice booms out...");
@@ -734,6 +746,7 @@ void
 intervene(void)
 {
     int which = Is_astralevel(&u.uz) ? rnd(4) : rn2(6);
+
     /* cases 0 and 5 don't apply on the Astral level */
     switch (which) {
     case 0: