DOC: Add (object) equality changes and error raising to release notes

1 files changed, 20 insertions, 0 deletions

diff --git a/doc/release/1.9.0-notes.rst b/doc/release/1.9.0-notes.rst
index 4b1e094ad..35c8c6d8e 100644
--- a/doc/release/1.9.0-notes.rst
+++ b/doc/release/1.9.0-notes.rst
@@ -352,6 +352,26 @@ considered an input error instead of returning the default.
 The ``rank`` function has been deprecated to avoid confusion with
 ``numpy.linalg.matrix_rank``.
 
+Object array equality comparisons
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+In the future object array comparisons both `==` and `np.equal` will not
+make use of identity checks anymore. For example:
+
+>>> a = np.array([np.array([1, 2, 3]), 1])
+>>> b = np.array([np.array([1, 2, 3]), 1])
+>>> a == b
+
+will consistently return False (and in the future an error) even if the array
+in `a` and `b` was the same object.
+
+The equality operator `==` will in the future raise errors like `np.equal`
+if broadcasting or element comparisons, etc. fails.
+
+Comparison with `arr == None` will in the future do an elementwise comparison
+instead of just returning False. Code should be using `arr is None`.
+
+All of these changes will give Deprecation- or FutureWarnings at this time.
+
 C-API
 ~~~~~