Fire-13997. When an object is derendered it might get added again from cache. Kill that new copy too.

indra/newview/llviewerobjectlist.cpp

@@ -1443,6 +1443,8 @@ BOOL LLViewerObjectList::killObject(LLViewerObject *objectp)
 
 	if (objectp)
 	{
+		mDerendered.insert( objectp->getID() ); // <FS:ND> Remember this object it case it comes back.
+
 		objectp->markDead(); // does the right thing if object already dead
 		return TRUE;
 	}
@@ -2168,6 +2170,11 @@ LLViewerObject *LLViewerObjectList::createObjectFromCache(const LLPCode pcode, L
 	
 	updateActive(objectp);
 
+	// <FS:ND> We might have killed this object earlier, but it might get resurrected from fastcache. Kill it again to make sure it stays dead.
+	if( mDerendered.end() != mDerendered.find( uuid ) )
+		killObject( objectp );
+	// </FS:ND>
+
 	return objectp;
 }
 
@@ -2206,6 +2213,11 @@ LLViewerObject *LLViewerObjectList::createObject(const LLPCode pcode, LLViewerRe
 
 	updateActive(objectp);
 
+	// <FS:ND> We might have killed this object earlier, but it might get resurrected from fastcache. Kill it again to make sure it stays dead.
+	if( mDerendered.end() != mDerendered.find( uuid ) )
+		killObject( objectp );
+	// </FS:ND>
+
 	return objectp;
 }
 

indra/newview/llviewerobjectlist.h

@@ -234,6 +234,11 @@ protected:
 	std::set<LLViewerObject *> mSelectPickList;
 
 	friend class LLViewerObject;
+
+// <FS:ND> Remember objects we did derender. We might get object updates for them that create new instances. In those cases we kill them again.
+private:
+	std::set< LLUUID > mDerendered;
+// </FS:ND>
 };