From 0eced2d273535577645493340c7319ebf27a559c Mon Sep 17 00:00:00 2001
From: Neal Gompa <ngompa13@gmail.com>
Date: Fri, 16 Oct 2020 03:47:38 -0400
Subject: [PATCH] Use importlib.resources for Python 3.9+ and
 importlib_resources otherwise

This makes it possible to use Mailman 3 in environments where importlib_resources
is not available.

Signed-off-by: Neal Gompa <ngompa13@gmail.com>
---
 setup.py                        |  2 +-
 src/mailman/__init__.py         |  5 +++++
 src/mailman/testing/__init__.py | 23 +++++++++++++++++++++++
 3 files changed, 29 insertions(+), 1 deletion(-)

diff --git a/setup.py b/setup.py
index cd3645611..6d871fbfd 100644
--- a/setup.py
+++ b/setup.py
@@ -121,7 +121,7 @@ case second 'm'.  Any other spelling is incorrect.""",
         'flufl.bounce',
         'flufl.i18n>=2.0',
         'flufl.lock>=3.1',
-        'importlib_resources>=1.1.0',
+        'importlib_resources>=1.1.0 ; python_version<"3.9"',
         'gunicorn',
         'lazr.config',
         'python-dateutil>=2.0',
diff --git a/src/mailman/__init__.py b/src/mailman/__init__.py
index 2d94288e0..1c760008d 100644
--- a/src/mailman/__init__.py
+++ b/src/mailman/__init__.py
@@ -37,3 +37,8 @@ if 'build_sphinx' not in sys.argv:                  # pragma: nocover
     else:
         from mailman.core.i18n import initialize
     initialize()
+
+# Switch over to the internal importlib.resources module on Python 3.9+
+if sys.version_info >= (3, 9, 0):
+    import importlib.resources
+    sys.modules['importlib_resources'] = importlib.resources
diff --git a/src/mailman/testing/__init__.py b/src/mailman/testing/__init__.py
index e69de29bb..2b2ed536a 100644
--- a/src/mailman/testing/__init__.py
+++ b/src/mailman/testing/__init__.py
@@ -0,0 +1,23 @@
+# Copyright (C) 2009-2020 by the Free Software Foundation, Inc.
+#
+# This file is part of GNU Mailman.
+#
+# GNU Mailman is free software: you can redistribute it and/or modify it under
+# the terms of the GNU General Public License as published by the Free
+# Software Foundation, either version 3 of the License, or (at your option)
+# any later version.
+#
+# GNU Mailman is distributed in the hope that it will be useful, but WITHOUT
+# ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+# FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
+# more details.
+#
+# You should have received a copy of the GNU General Public License along with
+# GNU Mailman.  If not, see <https://www.gnu.org/licenses/>.
+
+import sys
+
+# Switch over to the internal importlib.resources module on Python 3.9+
+if sys.version_info >= (3, 9, 0):
+    import importlib.resources
+    sys.modules['importlib_resources'] = importlib.resources
-- 
2.30.1