Veto chaos cloning of battlespheres

Several assumptions of the spell rely on there never being more than
one battlesphere belonging to a single actor. If a battlesphere became
cloned, the expiry of the effect would only remove the first one, and
this would cause a crash when you tried to recast.

1 files changed, 4 insertions, 2 deletions

diff --git a/crawl-ref/source/mon-clone.cc b/crawl-ref/source/mon-clone.cc
index d0d57d996c..3de4961984 100644
--- a/crawl-ref/source/mon-clone.cc
+++ b/crawl-ref/source/mon-clone.cc
@@ -216,10 +216,12 @@ void mons_summon_illusion_from(monster* mons, actor *foe,
 bool mons_clonable(const monster* mon, bool needs_adjacent)
 {
     // No uniques or ghost demon monsters.  Also, figuring out the name
-    // for the clone of a named monster isn't worth it.
+    // for the clone of a named monster isn't worth it, and duplicate
+    // battlespheres with the same owner cause problems with the spell
     if (mons_is_unique(mon->type)
         || mons_is_ghost_demon(mon->type)
-        || mon->is_named())
+        || mon->is_named()
+        || mon->type == MONS_BATTLESPHERE)
     {
         return false;
     }