Merge pull request #15381 from sethtroisi/matlib_namespace

DEP: add PendingDeprecation to matlib.py funky namespace

4 files changed, 16 insertions, 9 deletions

diff --git a/numpy/_pytesttester.py b/numpy/_pytesttester.py
index e573d53ab..0dc38fa59 100644
--- a/numpy/_pytesttester.py
+++ b/numpy/_pytesttester.py
@@ -153,6 +153,7 @@ class PytestTester:
         # When testing matrices, ignore their PendingDeprecationWarnings
         pytest_args += [
             "-W ignore:the matrix subclass is not",
+            "-W ignore:Importing from numpy.matlib is",
             ]
 
         if doctests:
diff --git a/numpy/matlib.py b/numpy/matlib.py
index 1f0345be4..bd6b63289 100644
--- a/numpy/matlib.py
+++ b/numpy/matlib.py
@@ -1,6 +1,19 @@
+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
-# need * as we're copying the numpy namespace (FIXME: this makes little sense)
+# Matlib.py contains all functions in the numpy namespace with a few
+# replacements. See doc/source/reference/routines.matlib.rst for details.
+# Need * as we're copying the numpy namespace.
 from numpy import *  # noqa: F403
 
 __version__ = np.__version__
diff --git a/numpy/tests/test_matlib.py b/numpy/tests/test_matlib.py
index e04947a2e..0e93c4848 100644
--- a/numpy/tests/test_matlib.py
+++ b/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_
diff --git a/pytest.ini b/pytest.ini
index 480130337..0db7f80dd 100644
--- a/pytest.ini
+++ b/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