Update to SFrame serialization to fix issues with python 2.7 and cloudpickle. (#3333)

* Update to fix issue with python 2.7 and cloudpickle.

* Addressed PR feedback.

Co-authored-by: Hoyt Koepke <[email protected]>

Author: Hoyt Koepke

src/python/turicreate/data_structures/serialization.py

@@ -8,6 +8,7 @@
 # SFrames require a disk-backed file or directory to work with.  This directory 
 # has to be present to allow for serialization or deserialization. 
 __serialization_directory = None 
+from sys import version_info as _version_info
 
 
 def enable_sframe_serialization(serialization_directory):
@@ -28,6 +29,8 @@ def enable_sframe_serialization(serialization_directory):
 
     import os
 
+    if _version_info[0] == 2:
+        raise RuntimeError("SFrame serialization not supported in python 2.")
     global __serialization_directory
     if serialization_directory is None:
         __serialization_directory = None
@@ -61,7 +64,10 @@ def _safe_serialization_directory():
     from pickle import PickleError
 
     if __serialization_directory is None:
-        raise PickleError("Serialization directory not set to enable pickling or unpickling. "
+        
+        expected_error = TypeError if (_version_info[0] == 3) else PickleError
+
+        raise expected_error("Serialization directory not set to enable pickling or unpickling. "
             "Set using turicreate.data_structures.serialization.enable_sframe_serialization().")
 
     return __serialization_directory

src/python/turicreate/test/test_sframe.py

@@ -12,6 +12,7 @@
 from ..util import _assert_sframe_equal, generate_random_sframe
 from .. import _launch, load_sframe, aggregate
 from . import util
+from sys import version_info
 
 import pandas as pd
 from .._cython.cy_flexible_type import GMT
@@ -642,6 +643,7 @@ def test_save_to_csv(self):
         f.close()
         os.unlink(f.name)
 
+    @pytest.mark.skipif(version_info[0] != 3, "Not a supported feature in python 2.7")
     def test_pickling(self):
 
         import pickle
@@ -650,9 +652,10 @@ def test_pickling(self):
         X = generate_random_sframe(100, "ncc")
 
         with util.TempDirectory() as f:
-            
 
-            self.assertRaises(pickle.PickleError, lambda: pickle.dumps(X))
+            expected_error = TypeError if (version_info[0] == 3) else PicklingError
+
+            self.assertRaises(expected_error, lambda: pickle.dumps(X))
 
             serialization.enable_sframe_serialization(f)