Merge pull request #48 from navytux/slots-delfixup

py/deactivate vs slots: A slot variable could not be initialized at all

persistent/persistence.py

@@ -428,7 +428,12 @@ class Persistent(object):
         #   class does not override __new__ )
         if type_.__new__ is Persistent.__new__:
             for slotname in Persistent._slotnames(self, _v_exclude=False):
-                getattr(type_, slotname).__delete__(self)
+                try:
+                    getattr(type_, slotname).__delete__(self)
+                except AttributeError:
+                    # AttributeError means slot variable was not initialized at all -
+                    # - we can simply skip its deletion.
+                    pass
 
         # Implementation detail: deactivating/invalidating
         # updates the size of the cache (if we have one)

persistent/tests/test_persistence.py

@@ -1321,7 +1321,7 @@ class _Persistent_Base(object):
 
     def test__p_invalidate_from_changed_w_slots(self):
         class Derived(self._getTargetClass()):
-            __slots__ = ('myattr1', 'myattr2')
+            __slots__ = ('myattr1', 'myattr2', 'unset')
             def __init__(self):
                 self.myattr1 = 'value1'
                 self.myattr2 = 'value2'