Rollback some changes now that Python persistent handles registering objects...

Rollback some changes now that Python persistent handles registering objects during __setstate__ the same way as C persistent.

.travis.yml

@@ -2,6 +2,7 @@ language: python
 sudo: false
 python:
     - pypy
+    - pypy3
     - 2.6
     - 2.7
     - 3.2

src/ZODB/blob.py

@@ -76,14 +76,7 @@ class Blob(persistent.Persistent):
     _p_blob_committed = None    # Filename of the committed data
     _p_blob_ref = None          # weakreference to self; also in _blob_close_refs
 
-    # Use volatile attributes so as not to spuriously mark as changed.
-    # The properties are aliases for BWC
-    readers = property(lambda self: getattr(self, '_v_readers', None),
-                       lambda self, nv: setattr(self, '_v_readers', nv))
-    writers = property(lambda self: getattr(self, '_v_writers', None),
-                       lambda self, nv: setattr(self, '_v_writers', nv))
-    _v_readers = None
-    _v_writers = None
+    readers = writers = None
 
     def __init__(self, data=None):
         # Raise exception if Blobs are getting subclassed
@@ -98,14 +91,8 @@ class Blob(persistent.Persistent):
     def __setstate__(self, state=None):
         # we use lists here because it will allow us to add and remove
         # atomically
-        # Directly use the volatile attributes here, not the property,
-        # because setting the property causes us to get marked as changed,
-        # which registers us with the Connection and hence the transaction;
-        # at least under the Python implementation of persistent this causes
-        # duplicate transaction errors from the storage in testblob.
-        # Plus this way is more efficient anyway :)
-        self._v_readers = []
-        self._v_writers = []
+        self.readers = []
+        self.writers = []
 
     def __getstate__(self):
         return None
@@ -164,8 +151,8 @@ class Blob(persistent.Persistent):
         if self.writers:
             raise BlobError("Already opened for writing.")
 
-        if self._v_readers is None:
-            self._v_readers = []
+        if self.readers is None:
+            self.readers = []
 
         if mode == 'r':
             result = None

src/ZODB/tests/testSerialize.py

@@ -177,7 +177,6 @@ def _functest_load(fqn):
     # Open the database and attempt to deserialize the tree
     # (run in separate process)
     from ZODB import DB
-    import transaction
     WORKING, FAILING = _working_failing_datetimes()
     db = DB(fqn)
     conn = db.open()
@@ -186,7 +185,6 @@ def _functest_load(fqn):
         tree = root['tree']
         assert tree[WORKING] == 'working'
         assert tree[FAILING] == 'failing'
-        transaction.abort()
     finally: # Windoze
         conn.close()
         db.close()

src/ZODB/tests/test_cache.py

@@ -52,7 +52,7 @@ class RegularObject(Persistent):
 class PersistentObject(Persistent):
     pass
 
-class CacheTests(object):
+class CacheTests:
 
     def test_cache(self):
         r"""Test basic cache methods.

tox.ini

 [tox]
-envlist = py26,py27,py32,py33,py34,pypy,simple
+envlist = py26,py27,py32,py33,py34,pypy,simple,pypy3
 
 [testenv]
 commands =