ENH: switch mpl_toolkits to implicit namespace package (PEP 420)

neutrinoceros · neutrinoceros · commit fabec26dfda4 · 2023-03-07T00:05:24.000+01:00
diff --git a/doc/users/next_whats_new/mpl_toolkit_pep420.rst b/doc/users/next_whats_new/mpl_toolkit_pep420.rst
@@ -0,0 +1,9 @@
+``matplotlib.mpl_toolkits`` is now an implicit namespace package
+----------------------------------------------------------------
+
+Following the deprecation of ``pkg_resources.declare_namespace`` in ``setuptools`` 67.3.0,
+``matplotlib.mpl_toolkits`` is now implemented as an implicit namespace, following
+`PEP 420 <https://peps.python.org/pep-0420/>`_.
+
+This change should be backward compatible. In case of problems please `file an issue on GitHub
+<https://github.com/matplotlib/matplotlib/issues/new/choose>`_.
diff --git a/lib/mpl_toolkits/__init__.py b/lib/mpl_toolkits/__init__.py
diff --git a/setup.py b/setup.py
@@ -29,7 +29,7 @@
 import shutil
 import subprocess
 
-from setuptools import setup, find_packages, Distribution, Extension
+from setuptools import setup, find_namespace_packages, Distribution, Extension
 import setuptools.command.build_ext
 import setuptools.command.build_py
 import setuptools.command.sdist
@@ -300,8 +300,7 @@ def make_release_tree(self, base_dir, files):
     ],
 
     package_dir={"": "lib"},
-    packages=find_packages("lib"),
-    namespace_packages=["mpl_toolkits"],
+    packages=find_namespace_packages(where="lib"),
     py_modules=["pylab"],
     # Dummy extension to trigger build_ext, which will swap it out with
     # real extensions that can depend on numpy for the build.
