Forward-port fix and tests for issue #2157 from 2.8 branch.

doc/CHANGES.txt

@@ -18,6 +18,9 @@ Zope Changes
 
    Bugs fixed
 
+      - Collector #2157: Expose name of broken class in SystemError raised
+        from '__getstate__' of a broken instance.
+
       - Usage of 'urljoin' in 'webdav.davcmds' could lead to wrongly
         constructed urls.
 

lib/python/OFS/Uninstalled.py

@@ -40,7 +40,7 @@ class BrokenClass(Acquisition.Explicit, SimpleItem.Item,
         raise SystemError, (
             """This object was originally created by a product that
             is no longer installed.  It cannot be updated.
-            """)
+            (%s)""" % repr(self))
 
     def __getattr__(self, name):
         if name[:3]=='_p_':