Pickling working

Author: TomAugspurger

pandas/core/categorical.py

@@ -345,13 +345,6 @@ def __init__(self, values, categories=None, ordered=False, fastpath=False):
         self._dtype = dtype
         self._codes = coerce_indexer_dtype(codes, dtype.categories)
 
-    def __getstate__(self):
-        # import pdb; pdb.set_trace()
-        pass
-    def __setstate__(self):
-        # import pdb; pdb.set_trace()
-        super().__setstate__()
-
     @property
     def categories(self):
         return self.dtype.categories

pandas/core/dtypes/dtypes.py

@@ -209,6 +209,9 @@ def __unicode__(self):
     def __repr__(self):
         return str(self)
 
+    def __getnewargs__(self):
+        return (self.categories, self.ordered)
+
     @staticmethod
     def _hash_categories(categories, ordered=True):
         from pandas.core.util.hashing import (

pandas/tests/dtypes/test_common.py

@@ -543,10 +543,11 @@ def test_is_complex_dtype():
     (pd.Index([1, 2]), np.dtype('int64')),
     (pd.Index(['a', 'b']), np.dtype(object)),
     ('category', 'category'),
-    (pd.Categorical(['a', 'b']).dtype, CategoricalDtype()),
-    (pd.Categorical(['a', 'b']), CategoricalDtype()),
-    (pd.CategoricalIndex(['a', 'b']).dtype, CategoricalDtype()),
-    (pd.CategoricalIndex(['a', 'b']), CategoricalDtype()),
+    (pd.Categorical(['a', 'b']).dtype, CategoricalDtype(['a', 'b'])),
+    (pd.Categorical(['a', 'b']), CategoricalDtype(['a', 'b'])),
+    (pd.CategoricalIndex(['a', 'b']).dtype, CategoricalDtype(['a', 'b'])),
+    (pd.CategoricalIndex(['a', 'b']), CategoricalDtype(['a', 'b'])),
+    (CategoricalDtype(), CategoricalDtype()),
     (pd.DatetimeIndex([1, 2]), np.dtype('<M8[ns]')),
     (pd.DatetimeIndex([1, 2]).dtype, np.dtype('<M8[ns]')),
     ('<M8[ns]', np.dtype('<M8[ns]')),