Use pickle protocol 3 on the wire.

CHANGES.rst

 Changelog
 =========
 
-5.1.3 (unreleased)
+5.2.0 (unreleased)
 ------------------
 
 - Fix ``ZEO.server`` relying on test dependencies. See `issue 105
@@ -20,6 +20,10 @@ Changelog
   had ``zodbpickle.binary`` OIDs. See `issue 113
   <https://github.com/zopefoundation/ZEO/issues/113>`_.
 
+- ZEO now uses pickle protocol 3 for both Python 2 and Python 3.
+  (Previously protocol 1 was used for Python 2.) This matches the
+  change in ZODB 5.4.0.
+
 5.1.2 (2018-03-27)
 ------------------
 

src/ZEO/_compat.py

@@ -22,7 +22,7 @@ PYPY = getattr(platform, 'python_implementation', lambda: None)() == 'PyPy'
 WIN = sys.platform.startswith('win')
 
 if PY3:
-    from pickle import Pickler, Unpickler as _Unpickler, dump, dumps, loads
+    from zodbpickle.pickle import Pickler, Unpickler as _Unpickler, dump, dumps, loads
     class Unpickler(_Unpickler):
         # Py3: Python 3 doesn't allow assignments to find_global,
         # instead, find_class can be overridden
@@ -34,8 +34,15 @@ if PY3:
                 return super(Unpickler, self).find_class(modulename, name)
             return self.find_global(modulename, name)
 else:
-    # Pickle support
-    from cPickle import Pickler, Unpickler, dump, dumps, loads
+    try:
+        import zodbpickle.fastpickle as cPickle
+    except ImportError:
+        import zodbpickle.pickle as cPickle
+    Pickler = cPickle.Pickler
+    Unpickler = cPickle.Unpickler
+    dump = cPickle.dump
+    dumps = cPickle.dumps
+    loads = cPickle.loads
 
 # String and Bytes IO
 from ZODB._compat import BytesIO

src/ZEO/asyncio/marshal.py

@@ -42,25 +42,18 @@ def encoder(protocol, server=False):
     else:
         assert protocol[:1] == b'Z'
 
-    if PY3 or PYPY:
-        f = BytesIO()
-        getvalue = f.getvalue
-        seek = f.seek
-        truncate = f.truncate
-        pickler = Pickler(f, 3 if PY3 else 1)
-        pickler.fast = 1
-        dump = pickler.dump
-        def encode(*args):
-            seek(0)
-            truncate()
-            dump(args)
-            return getvalue()
-    else:
-        pickler = Pickler(1)
-        pickler.fast = 1
-        dump = pickler.dump
-        def encode(*args):
-            return dump(args, 2)
+    f = BytesIO()
+    getvalue = f.getvalue
+    seek = f.seek
+    truncate = f.truncate
+    pickler = Pickler(f, 3)
+    pickler.fast = 1
+    dump = pickler.dump
+    def encode(*args):
+        seek(0)
+        truncate()
+        dump(args)
+        return getvalue()
 
     return encode
 

src/ZEO/tests/ZEO4/zrpc/marshal.py

@@ -32,24 +32,13 @@ def encode(*args): # args: (msgid, flags, name, args)
     # being represented by \xij escapes in proto 0).
     # Undocumented:  cPickle.Pickler accepts a lone protocol argument;
     # pickle.py does not.
-    if PY3:
-        # XXX: Py3: Needs optimization.
-        f = BytesIO()
-        pickler = Pickler(f, 3)
-        pickler.fast = 1
-        pickler.dump(args)
-        res = f.getvalue()
-        return res
-    else:
-        pickler = Pickler(1)
-        pickler.fast = 1
-        # Only CPython's cPickle supports dumping
-        # and returning in one operation:
-        #   return pickler.dump(args, 1)
-        # For PyPy we must return the value; fortunately this
-        # works the same on CPython and is no more expensive
-        pickler.dump(args)
-        return pickler.getvalue()
+    # XXX: Py3: Needs optimization.
+    f = BytesIO()
+    pickler = Pickler(f, 3)
+    pickler.fast = 1
+    pickler.dump(args)
+    res = f.getvalue()
+    return res
 
 
 

src/ZEO/tests/testZEO.py

@@ -487,7 +487,9 @@ class ClientConflictResolutionTests(
         return '<mappingstorage>\n</mappingstorage>\n'
 
     def getZEOConfig(self):
-        return forker.ZEOConfig(('', 0), client_conflict_resolution=True)
+        # Using '' can result in binding to :: and cause problems
+        # connecting to the MTAcceptor on Travis CI
+        return forker.ZEOConfig(('127.0.0.1', 0), client_conflict_resolution=True)
 
 class MappingStorageTests(GenericTests):
     """ZEO backed by a Mapping storage."""