--- deliantra/server/ext/map-scheduler.ext	2007/01/02 21:13:22	1.7
+++ deliantra/server/ext/map-scheduler.ext	2007/01/03 12:33:33	1.9
@@ -13,7 +13,16 @@
    while () {
       Coro::Timer::sleep $SCHEDULE_INTERVAL;
 
-      for my $map (values %cf::MAP) {
+      # this weird form of iteration over values is used because
+      # the hash changes underneath us frequently, and for
+      # keeps a direct reference to the value without (in 5.8 perls)
+      # keeping a reference, so this is prone to crashes or worse.
+      my @maps = keys %cf::MAP;
+      for (@maps) {
+         my $map = $cf::MAP{$_}
+            or next;
+         $map->valid or next;
+
          eval {
             # not yet, because maps might become visible to players nearby
             # we need to remove the map from %cf::MAP and all tiled map links
@@ -35,7 +44,7 @@
          };
          warn $@ if $@;
          Coro::cede;
-      }
+      };
    }
 };