DOC: indexing/v0.15.0 docs

Author: jreback

doc/source/indexing.rst

@@ -52,6 +52,12 @@ indexing.
    should be avoided.  See :ref:`Returning a View versus Copy
    <indexing.view_versus_copy>`
 
+.. warning::
+
+   In 0.15.0 ``Index`` has internaly been refactored to no longer sub-class ``ndarray``
+   but instead subclass ``PandasObject``, similarly to the rest of the pandas objects. This should be
+   a transparent change with only very limited API implications (See the :ref:`Internal Refactoring <whatsnew_0150.refactoring>`)
+
 See the :ref:`cookbook<cookbook.selection>` for some advanced strategies
 
 Different Choices for Indexing (``loc``, ``iloc``, and ``ix``)
@@ -2164,7 +2170,7 @@ you can specify ``inplace=True`` to have the data change in place.
 
 .. versionadded:: 0.15.0
 
-``set_names``, ``set_levels``, and ``set_labels`` also take an optional 
+``set_names``, ``set_levels``, and ``set_labels`` also take an optional
 `level`` argument
 
 .. ipython:: python

doc/source/v0.15.0.txt

@@ -25,6 +25,12 @@ users upgrade to this version.
 
 - :ref:`Bug Fixes <whatsnew_0150.bug_fixes>`
 
+.. warning::
+
+   In 0.15.0 ``Index`` has internaly been refactored to no longer sub-class ``ndarray``
+   but instead subclass ``PandasObject``, similarly to the rest of the pandas objects. This change allows very easy sub-classing and creation of new index types. This should be
+   a transparent change with only very limited API implications (See the :ref:`Internal Refactoring <whatsnew_0150.refactoring>`)
+
 .. _whatsnew_0150.api:
 
 API changes
@@ -130,6 +136,30 @@ API changes
   dta files with strings longer than 244 characters raises a ``ValueError``. (:issue:`7858`)
 
 
+.. _whatsnew_0150.refactoring:
+
+Internal Refactoring
+~~~~~~~~~~~~~~~~~~~~
+
+In 0.15.0 ``Index`` has internaly been refactored to no longer sub-class ``ndarray``
+but instead subclass ``PandasObject``, similarly to the rest of the pandas objects. This change allows very easy sub-classing and creation of new index types. This should be
+a transparent change with only very limited API implications (:issue:`5080`,:issue:`7439`,:issue:`7796`)
+
+- pickles <= 0.8.0 may not work if they contain MultiIndexes.
+- you may need to unpickle < 0.15.0 pickles using ``pd.read_pickle`` rather than ``pickle.load``. See :ref:`pickle docs <io.pickle>`
+- boolean comparisons of ``DatetimeIndex`` that have ``NaT`` with ``ndarray`` ONLY work if the ndarray is on the right-handle side. An example of this limited case is:
+
+  .. ipython:: python
+
+     idx = pd.DatetimeIndex(['2014-01-01', pd.NaT])
+     arr = np.array([np.datetime64('2014-02-01 00:00Z'),np.datetime64('2014-02-01 00:00Z')])
+     idx>arr
+     idx<=arr
+     arr<=idx
+     arr>idx
+
+- ``:func:`~pandas.core.index.MultiIndex.repeat` now is available
+
 .. _whatsnew_0150.cat:
 
 Categoricals in Series/DataFrame