Replace use of sweet_pickle in naming, and delete sweet_pickle subpac…

…kage (#199)

* delete sweet_pickle subpackage and references to it.  Update its use in apptools.naming to use apptools.persistence or pickle from the standard library instead

* adding news fragment

* remove @classmethod on load_build

* finish merge

* add roundtrip test for object serializer

* rewrite test_two_stage_unpickler to use persistence instead of sweet pickle and remove test_global registry

* flake8

* convert test_class_mapping to use persistence

* flake8

* update test_state_function to use persistence

* delete apptools.sweet_pickle

* flake8

* remove/update any references to sweet_pickle in the comments

* apply suggestions from code review

README.rst

@@ -28,9 +28,6 @@ that is commonly needed by many applications
   listener of selected items in an application.
 - **apptools.scripting**: A framework for automatic recording of Python
   scripts.
-- **apptools.sweet_pickle**: Handles class-level versioning, to support
-  loading of saved data that exist over several generations of internal class
-  structures.
 - **apptools.undo**: Supports undoing and scripting application commands.
 
 Prerequisites

apptools/naming/object_serializer.py

@@ -18,12 +18,10 @@
 import logging
 from traceback import print_exc
 from os.path import splitext
-
-# import cPickle
-# import pickle
+import pickle
 
 # Enthought library imports.
-import apptools.sweet_pickle as sweet_pickle
+from apptools.persistence.versioned_unpickler import VersionedUnpickler
 from traits.api import HasTraits, Str
 
 
@@ -57,9 +55,7 @@ def load(self, path):
         f = open(path, "rb")
         try:
             try:
-                obj = sweet_pickle.load(f)
-            #                obj = cPickle.load(f)
-            #                obj = pickle.load(f)
+                 obj = VersionedUnpickler(f).load()
             except Exception as ex:
                 print_exc()
                 logger.exception(
@@ -89,9 +85,7 @@ def save(self, path, obj):
         # Pickle the object.
         f = open(actual_path, "wb")
         try:
-            sweet_pickle.dump(obj, f, 1)
-        #            cPickle.dump(obj, f, 1)
-        #            pickle.dump(obj, f, 1)
+            pickle.dump(obj, f, 1)
         except Exception as ex:
             logger.exception(
                 "Failed to pickle into file: %s, %s, object:%s"

apptools/naming/tests/test_object_serializer.py

@@ -0,0 +1,52 @@
+# (C) Copyright 2005-2020 Enthought, Inc., Austin, TX
+# All rights reserved.
+#
+# This software is provided without warranty under the terms of the BSD
+# license included in LICENSE.txt and may be redistributed only under
+# the conditions described in the aforementioned license. The license
+# is also available online at http://www.enthought.com/licenses/BSD.txt
+#
+# Thanks for using Enthought open source!
+import os
+import shutil
+import tempfile
+import unittest
+
+from traits.api import cached_property, HasTraits, Property, Str, Event
+
+from apptools.naming.api import ObjectSerializer
+
+
+class FooWithTraits(HasTraits):
+    """Dummy HasTraits class for testing ObjectSerizalizer."""
+
+    full_name = Str()
+
+    last_name = Property(depends_on="full_name")
+
+    event = Event()
+
+    @cached_property
+    def _get_last_name(self):
+        return self.full_name.split(" ")[-1]
+
+class TestObjectSerializer(unittest.TestCase):
+
+    def setUp(self):
+        self.tmpdir = tempfile.mkdtemp()
+        self.addCleanup(shutil.rmtree, self.tmpdir)
+        self.tmp_file = os.path.join(self.tmpdir, "tmp.pickle")
+
+    def test_save_load_roundtrip(self):
+        # Test HasTraits objects can be serialized and deserialized as expected
+        obj = FooWithTraits(full_name="John Doe")
+
+        serializer = ObjectSerializer()
+        serializer.save(self.tmp_file, obj)
+
+        self.assertTrue(serializer.can_load(self.tmp_file))
+        deserialized = serializer.load(self.tmp_file)
+
+        self.assertIsInstance(deserialized, FooWithTraits)
+        self.assertEqual(deserialized.full_name, "John Doe")
+        self.assertEqual(deserialized.last_name, "Doe")

apptools/sweet_pickle/tests/state_function_classes.py → apptools/persistence/tests/state_function_classes.py

@@ -11,8 +11,6 @@
 import logging
 
 # Enthought library imports
-import apptools.sweet_pickle as sweet_pickle
-from apptools.sweet_pickle.global_registry import _clear_global_registry
 from traits.api import Bool, Float, HasTraits, Int, Str
 
 

apptools/persistence/tests/test_class_mapping.py

@@ -0,0 +1,81 @@
+# -----------------------------------------------------------------------------
+#
+#  Copyright (c) 2006 by Enthought, Inc.
+#  All rights reserved.
+#
+#  Author: Dave Peterson <dpeterson@enthought.com>
+#
+# -----------------------------------------------------------------------------
+
+""" Tests the class mapping functionality of the enthought.pickle
+    framework.
+"""
+
+# Standard library imports.
+import io
+import pickle
+import unittest
+
+# Enthought library imports
+from apptools.persistence.versioned_unpickler import VersionedUnpickler
+from apptools.persistence.updater import Updater
+
+
+##############################################################################
+# Classes to use within the tests
+##############################################################################
+
+
+class Foo:
+    pass
+
+
+class Bar:
+    pass
+
+
+class Baz:
+    pass
+
+
+##############################################################################
+# class 'ClassMappingTestCase'
+##############################################################################
+
+
+class ClassMappingTestCase(unittest.TestCase):
+    """Originally tests for the class mapping functionality of the now deleted
+    apptools.sweet_pickle framework, converted to use apptools.persistence.
+    """
+
+    ##########################################################################
+    # 'TestCase' interface
+    ##########################################################################
+
+    ### public interface #####################################################
+
+    def test_unpickled_class_mapping(self):
+
+        class TestUpdater(Updater):
+            def __init__(self):
+                self.refactorings = {
+                    (Foo.__module__, Foo.__name__):
+                        (Bar.__module__, Bar.__name__),
+                    (Bar.__module__, Bar.__name__):
+                        (Baz.__module__, Baz.__name__),
+                }
+                self.setstates = {}
+
+        # Validate that unpickling the first class gives us an instance of
+        # the second class.
+        start = Foo()
+        test_file = io.BytesIO(pickle.dumps(start, 2))
+        end = VersionedUnpickler(test_file, updater=TestUpdater()).load()
+        self.assertIsInstance(end, Bar)
+
+        # Validate that unpickling the second class gives us an instance of
+        # the third class.
+        start = Bar()
+        test_file = io.BytesIO(pickle.dumps(start, 2))
+        end = VersionedUnpickler(test_file, updater=TestUpdater()).load()
+        self.assertIsInstance(end, Baz)

apptools/sweet_pickle/tests/test_state_function.py → apptools/persistence/tests/test_state_function.py

@@ -7,43 +7,35 @@
 #
 # -----------------------------------------------------------------------------
 
-""" Tests the state function functionality of the apptools.sweet_pickle
-    framework.
+""" These tests were originally for the the state function functionality of the
+now deleted apptools.sweet_pickle framework.  They have been modified here to
+use apptools.persistence instead.
 """
 
 # Standard library imports.
+import io
+import pickle
 import unittest
 import logging
 
 # Enthought library imports
-import apptools.sweet_pickle as sweet_pickle
-from apptools.sweet_pickle.global_registry import _clear_global_registry
-from traits.api import Bool, Float, HasTraits, Int, Str
+from apptools.persistence.tests.state_function_classes import Foo, Bar, Baz
+from apptools.persistence.versioned_unpickler import VersionedUnpickler
+from apptools.persistence.updater import Updater
 
 
 logger = logging.getLogger(__name__)
 
 
-##############################################################################
-# Classes to use within the tests
-##############################################################################
-
-# Need complete package name so that mapping matches correctly.
-# The problem here is the Python loader that will load the same module with
-# multiple names in sys.modules due to relative naming. Nice.
-from apptools.sweet_pickle.tests.state_function_classes import Foo, Bar, Baz
-
-##############################################################################
-# State functions to use within the tests
-##############################################################################
-
-
-def bar_state_function(state):
-    for old, new in [("b1", "b2"), ("f1", "f2"), ("i1", "i2"), ("s1", "s2")]:
-        state[new] = state[old]
-        del state[old]
-    state["_enthought_pickle_version"] = 2
-    return state
+class TestUpdater(Updater):
+    def __init__(self):
+        self.refactorings = {
+            (Foo.__module__, Foo.__name__):
+                (Bar.__module__, Bar.__name__),
+            (Bar.__module__, Bar.__name__):
+                (Baz.__module__, Baz.__name__),
+        }
+        self.setstates = {}
 
 
 ##############################################################################
@@ -52,8 +44,8 @@ def bar_state_function(state):
 
 
 class StateFunctionTestCase(unittest.TestCase):
-    """Tests the state function functionality of the apptools.sweet_pickle
-    framework.
+    """Originally tests for the state function functionality of the now deleted
+    apptools.sweet_pickle framework, converted to use apptools.persistence.
     """
 
     ##########################################################################
@@ -68,15 +60,8 @@ def setUp(self):
         Overridden here to ensure each test starts with an empty global
         registry.
         """
-        # Clear the global registry
-        _clear_global_registry()
-
-        # Cache a reference to the new global registry
-        self.registry = sweet_pickle.get_global_registry()
 
-        # Add the class mappings to the registry
-        self.registry.add_mapping_to_class(Foo.__module__, Foo.__name__, Bar)
-        self.registry.add_mapping_to_class(Bar.__module__, Bar.__name__, Baz)
+        self.updater = TestUpdater()
 
     ##########################################################################
     # 'StateFunctionTestCase' interface
@@ -89,47 +74,25 @@ def test_normal_setstate(self):
         there are no registered state functions in the class chain.
         """
         # Validate that unpickling the first class gives us an instance of
-        # the third class with the appropriate attribute values.  It will have
+        # the second class with the appropriate attribute values.  It will have
         # the default Foo values (because there is no state function to move
-        # them) and also the default Baz values (since they inherit the
+        # them) and also the default Bar values (since they inherit the
         # trait defaults because nothing overwrote the values.)
         start = Foo()
-        end = sweet_pickle.loads(sweet_pickle.dumps(start))
-        self.assertIsInstance(end, Baz)
+        test_file = io.BytesIO(pickle.dumps(start, 2))
+        end = VersionedUnpickler(test_file, updater=TestUpdater()).load()
+        self.assertIsInstance(end, Bar)
         self._assertAttributes(end, 1, (False, 1, 1, "foo"))
-        self._assertAttributes(end, 2, None)
-        self._assertAttributes(end, 3, (False, 3, 3, "baz"))
+        self._assertAttributes(end, 2, (True, 2, 2, "bar"))
+        self._assertAttributes(end, 3, None)
 
         # Validate that unpickling the second class gives us an instance of
         # the third class with the appropriate attribute values.  It will have
         # only the Baz attributes with the Bar values (since the __setstate__
         # on Baz converted the Bar attributes to Baz attributes.)
         start = Bar()
-        end = sweet_pickle.loads(sweet_pickle.dumps(start))
-        self.assertIsInstance(end, Baz)
-        self._assertAttributes(end, 2, None)
-        self._assertAttributes(end, 3, (True, 2, 2, "bar"))
-
-    def test_unpickled_chain_functionality(self):
-        """Validates that the registered state functions are used when
-        unpickling.
-        """
-        # Add the state function to the registry
-        self.registry.add_state_function_for_class(Bar, 2, bar_state_function)
-
-        # Validate that unpickling the first class gives us an instance of
-        # the third class with the appropriate attribute values.
-        start = Foo()
-        end = sweet_pickle.loads(sweet_pickle.dumps(start))
-        self.assertIsInstance(end, Baz)
-        self._assertAttributes(end, 1, None)
-        self._assertAttributes(end, 2, None)
-        self._assertAttributes(end, 3, (False, 1, 1, "foo"))
-
-        # Validate that unpickling the second class gives us an instance of
-        # the third class.
-        start = Bar()
-        end = sweet_pickle.loads(sweet_pickle.dumps(start))
+        test_file = io.BytesIO(pickle.dumps(start, 2))
+        end = VersionedUnpickler(test_file, updater=TestUpdater()).load()
         self.assertIsInstance(end, Baz)
         self._assertAttributes(end, 2, None)
         self._assertAttributes(end, 3, (True, 2, 2, "bar"))