DEP: deprecate importing numpy/matrixlib.py

Author: sethtroisi

numpy/_pytesttester.py

@@ -153,6 +153,7 @@ def __call__(self, label='fast', verbose=1, extra_argv=None,
         # When testing matrices, ignore their PendingDeprecationWarnings
         pytest_args += [
             "-W ignore:the matrix subclass is not",
+            "-W ignore:Importing from numpy.matlib is",
             ]
 
         if doctests:

numpy/matlib.py

@@ -1,3 +1,14 @@
+import warnings
+
+# 2018-05-29, PendingDeprecationWarning added to matrix.__new__
+# 2020-01-23, numpy 1.19.0 PendingDeprecatonWarning
+warnings.warn("Importing from numpy.matlib is deprecated since 1.19.0. "
+              "The matrix subclass is not the recommended way to represent "
+              "matrices or deal with linear algebra (see "
+              "https://docs.scipy.org/doc/numpy/user/numpy-for-matlab-users.html). "
+              "Please adjust your code to use regular ndarray. ",
+              PendingDeprecationWarning, stacklevel=2)
+
 import numpy as np
 from numpy.matrixlib.defmatrix import matrix, asmatrix
 # Matlib.py contains all functions in the numpy namespace with a few

numpy/tests/test_matlib.py

@@ -1,11 +1,3 @@
-# As we are testing matrices, we ignore its PendingDeprecationWarnings
-try:
-    import pytest
-    pytestmark = pytest.mark.filterwarnings(
-        'ignore:the matrix subclass is not:PendingDeprecationWarning')
-except ImportError:
-    pass
-
 import numpy as np
 import numpy.matlib
 from numpy.testing import assert_array_equal, assert_

pytest.ini

@@ -13,6 +13,7 @@ filterwarnings =
     ignore::UserWarning:cpuinfo,
 # Matrix PendingDeprecationWarning.
     ignore:the matrix subclass is not
+    ignore:Importing from numpy.matlib is
 
 env =
     PYTHONHASHSEED=0