ENH: Make the ndarray diagonal method return a view.

Also remove the test_diagonal_deprecation test and add test that
checks that a view is returned and that it is not writeable.

Closes #596.

1 files changed, 7 insertions, 8 deletions

diff --git a/numpy/core/fromnumeric.py b/numpy/core/fromnumeric.py
index ca18d64ea..8d2c6ac95 100644
--- a/numpy/core/fromnumeric.py
+++ b/numpy/core/fromnumeric.py
@@ -1125,16 +1125,15 @@ def diagonal(a, offset=0, axis1=0, axis2=1):
     In versions of NumPy prior to 1.7, this function always returned a new,
     independent array containing a copy of the values in the diagonal.
 
-    In NumPy 1.7, it continues to return a copy of the diagonal, but depending
-    on this fact is deprecated. Writing to the resulting array continues to
-    work as it used to, but a FutureWarning will be issued.
+    In NumPy 1.7 and 1.8, it continues to return a copy of the diagonal,
+    but depending on this fact is deprecated. Writing to the resulting
+    array continues to work as it used to, but a FutureWarning is issued.
 
-    In NumPy 1.9, it will switch to returning a read-only view on the original
-    array. Attempting to write to the resulting array will produce an error.
+    In NumPy 1.9 it returns a read-only view on the original array.
+    Attempting to write to the resulting array will produce an error.
 
-    In NumPy 1.10, it will still return a view, but this view will no longer be
-    marked read-only. Writing to the returned array will alter your original
-    array as well.
+    In NumPy 1.10, it will return a read/write view, Writing to the returned
+    array will alter your original array.
 
     If you don't write to the array returned by this function, then you can
     just ignore all of the above.