FIX pickling for ABC in python3.7

.travis.yml

@@ -1,15 +1,18 @@
 language: python
-sudo: false
-python:
-  - "2.7"
-  - "3.4"
-  - "3.5"
-  - "3.6"
-  - "pypy"
+
+matrix:
+  include:
+    - python: 2.7
+    - python: 3.5
+    - python: 3.6
+    - python: 3.7
+      sudo: required
+      dist: xenial
+    - python: "pypy"
+
 
 # This disables sudo, but makes builds start much faster
 # See http://blog.travis-ci.com/2014-12-17-faster-builds-with-container-based-infrastructure/
-sudo: false
 before_install: bash ./ci/before_install.sh
 install:
   - if [[ $TRAVIS_PYTHON_VERSION != 'pypy'* ]]; then source activate testenv; fi

ci/before_install.sh

@@ -1,8 +1,9 @@
 #!/bin/bash
 
 # if python version is not PyPY, then install miniconda
-if [[ $TRAVIS_PYTHON_VERSION != 'pypy'* ]]
+if [[ $TRAVIS_PYTHON_VERSION != 'pypy'* && $TRAVIS_PYTHON_VERSION != "3.7" ]]
 then
+
     # Escape standard Travis virtualenv
     deactivate
     # See: http://conda.pydata.org/docs/travis.html
@@ -14,4 +15,4 @@ then
     conda update -q conda
     conda info -a
     conda create -q -n testenv python=$TRAVIS_PYTHON_VERSION numpy scipy pip
-fi
+fi

cloudpickle/cloudpickle.py

@@ -460,6 +460,15 @@ def save_dynamic_class(self, obj):
         clsdict = dict(obj.__dict__)  # copy dict proxy to a dict
         clsdict.pop('__weakref__', None)
 
+        # For ABCMeta in python3.7+, remove _abc_impl as it is not picklable.
+        # This is a fix which breaks the cache but this only makes the first
+        # calls to issubclass slower.
+        if "_abc_impl" in clsdict:
+            import abc
+            (registry, _, _, _) = abc._get_dump(obj)
+            clsdict["_abc_impl"] = [subclass_weakref()
+                                    for subclass_weakref in registry]
+
         # On PyPy, __doc__ is a readonly attribute, so we need to include it in
         # the initial skeleton class.  This is safe because we know that the
         # doc can't participate in a cycle with the original class.
@@ -1082,8 +1091,16 @@ def _rehydrate_skeleton_class(skeleton_class, class_dict):
 
     See CloudPickler.save_dynamic_class for more info.
     """
+    registry = None
     for attrname, attr in class_dict.items():
-        setattr(skeleton_class, attrname, attr)
+        if attrname == "_abc_impl":
+            registry = attr
+        else:
+            setattr(skeleton_class, attrname, attr)
+    if registry is not None:
+        for subclass in registry:
+            skeleton_class.register(subclass)
+
     return skeleton_class
 
 

tests/cloudpickle_test.py

@@ -655,11 +655,18 @@ class ConcreteClass(AbstractClass):
             def foo(self):
                 return 'it works!'
 
+        # This class is local so we can safely register tuple in it to verify
+        # the unpickled class also register tuple.
+        AbstractClass.register(tuple)
+
         depickled_base = pickle_depickle(AbstractClass, protocol=self.protocol)
         depickled_class = pickle_depickle(ConcreteClass,
                                           protocol=self.protocol)
         depickled_instance = pickle_depickle(ConcreteClass())
 
+        assert issubclass(tuple, AbstractClass)
+        assert issubclass(tuple, depickled_base)
+
         self.assertEqual(depickled_class().foo(), 'it works!')
         self.assertEqual(depickled_instance.foo(), 'it works!')
 

tox.ini

@@ -1,5 +1,5 @@
 [tox]
-envlist = py27, py34, py35, py36, pypy, pypy3
+envlist = py27, py34, py35, py36, py37, pypy, pypy3
 
 [testenv]
 deps = -rdev-requirements.txt