Something

Index: parse_py/BBHandler.py
===================================================================
--- parse_py/BBHandler.py       (revision 1009)
+++ parse_py/BBHandler.py       (working copy)
@@ -95,6 +95,10 @@
     if ext == ".bbclass":
         __classname__ = root
         classes.append(__classname__)
+        __inherit_cache = data.getVar('__inherit_cache', d) or []
+        if not fn in __inherit_cache:
+            __inherit_cache.append(fn)
+            data.setVar('__inherit_cache', __inherit_cache, d)
 
     if include != 0:
         oldfile = data.getVar('FILE', d)