Make HasTraits pickleable

The main change is storing method names instead of functions in `trait_dyn_inits`.
These functions were failing to pickle.

IPython/utils/tests/test_traitlets.py

@@ -1,26 +1,13 b''
 # encoding: utf-8
-"""
-Tests for IPython.utils.traitlets.
+"""Tests for IPython.utils.traitlets."""
 
-Authors:
-
-* Brian Granger
-* Enthought, Inc.  Some of the code in this file comes from enthought.traits
-  and is licensed under the BSD license.  Also, many of the ideas also come
-  from enthought.traits even though our implementation is very different.
-"""
-
-#-----------------------------------------------------------------------------
-#  Copyright (C) 2008-2011  The IPython Development Team
+# Copyright (c) IPython Development Team.
+# Distributed under the terms of the Modified BSD License.
 #
-#  Distributed under the terms of the BSD License.  The full license is in
-#  the file COPYING, distributed as part of this software.
-#-----------------------------------------------------------------------------
-
-#-----------------------------------------------------------------------------
-# Imports
-#-----------------------------------------------------------------------------
+# Adapted from enthought.traits, Copyright (c) Enthought, Inc.,
+# also under the terms of the Modified BSD License.
 
+import pickle
 import re
 import sys
 from unittest import TestCase
@@ -1093,3 +1080,29 b' class TestLink(TestCase):'
         a.value = 4
         self.assertEqual(''.join(callback_count), 'ab')
         del callback_count[:]
+
+class Pickleable(HasTraits):
+    i = Int()
+    j = Int()
+    
+    def _i_default(self):
+        return 1
+    
+    def _i_changed(self, name, old, new):
+        self.j = new
+
+def test_pickle_hastraits():
+    c = Pickleable()
+    for protocol in range(pickle.HIGHEST_PROTOCOL + 1):
+        p = pickle.dumps(c, protocol)
+        c2 = pickle.loads(p)
+        nt.assert_equal(c2.i, c.i)
+        nt.assert_equal(c2.j, c.j)
+
+    c.i = 5
+    for protocol in range(pickle.HIGHEST_PROTOCOL + 1):
+        p = pickle.dumps(c, protocol)
+        c2 = pickle.loads(p)
+        nt.assert_equal(c2.i, c.i)
+        nt.assert_equal(c2.j, c.j)
+    
  No newline at end of file

IPython/utils/traitlets.py

@@ -32,25 +32,13 b' Inheritance diagram:'
 
 .. inheritance-diagram:: IPython.utils.traitlets
    :parts: 3
-
-Authors:
-
-* Brian Granger
-* Enthought, Inc.  Some of the code in this file comes from enthought.traits
-  and is licensed under the BSD license.  Also, many of the ideas also come
-  from enthought.traits even though our implementation is very different.
 """
 
-#-----------------------------------------------------------------------------
-#  Copyright (C) 2008-2011  The IPython Development Team
+# Copyright (c) IPython Development Team.
+# Distributed under the terms of the Modified BSD License.
 #
-#  Distributed under the terms of the BSD License.  The full license is in
-#  the file COPYING, distributed as part of this software.
-#-----------------------------------------------------------------------------
-
-#-----------------------------------------------------------------------------
-# Imports
-#-----------------------------------------------------------------------------
+# Adapted from enthought.traits, Copyright (c) Enthought, Inc.,
+# also under the terms of the Modified BSD License.
 
 import contextlib
 import inspect
@@ -332,7 +320,7 b' class TraitType(object):'
             obj._trait_values[self.name] = newdv
             return
         # Complete the dynamic initialization.
-        obj._trait_dyn_inits[self.name] = cls.__dict__[meth_name]
+        obj._trait_dyn_inits[self.name] = meth_name
 
     def __get__(self, obj, cls=None):
         """Get the value of the trait by self.name for the instance.
@@ -350,7 +338,8 b' class TraitType(object):'
             except KeyError:
                 # Check for a dynamic initializer.
                 if self.name in obj._trait_dyn_inits:
-                    value = obj._trait_dyn_inits[self.name](obj)
+                    method = getattr(obj, obj._trait_dyn_inits[self.name])
+                    value = method()
                     # FIXME: Do we really validate here?
                     value = self._validate(obj, value)
                     obj._trait_values[self.name] = value