Preparation for Django 3.0 and 3.1 support (2)

django-pyscss is not compatible with Django 3.0.
django_pyscss_fix is a temporary workaround for django.utils.six
used in django-pyscss. It also add six in requirements.txt
as we use six module for this workaround.
This is just to run horizon for testing with Django 3.0+.

six is re-added to requirements.txt as it is used in the workaround.
Note that other codes in the horizon repo should not depend on six.

Change-Id: If79289b7518dd8eaf292a90d6fb790beb154cb7c

horizon/test/django_pyscss_fix/__init__.py

@@ -0,0 +1,24 @@
+# Licensed under the Apache License, Version 2.0 (the "License"); you may
+# not use this file except in compliance with the License. You may obtain
+# a copy of the License at
+#
+# http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+# License for the specific language governing permissions and limitations
+# under the License.
+
+import sys
+
+import django
+import six
+import six.moves
+
+# Temporary workaround for a situation that django-pyscss depends on
+# a vendored version of six, django.utils.six which was dropped in Django 3.0.
+# TODO(amotoki): Drop the workaround once django-pyscss supports Django 3.0+.
+if django.VERSION[0] >= 3:
+    sys.modules['django.utils.six'] = six
+    sys.modules['django.utils.six.moves'] = six.moves

horizon/test/settings.py

@@ -51,6 +51,7 @@ INSTALLED_APPS = (
     'django.contrib.humanize',
     'django.contrib.auth',
     'django.contrib.contenttypes',
+    'horizon.test.django_pyscss_fix',
     'django_pyscss',
     'compressor',
     'horizon',

lower-constraints.txt

@@ -110,7 +110,7 @@ Routes==2.3.1
 selenium==2.50.1
 semantic-version==2.3.1
 simplejson==3.5.1
-six==1.12.0
+six==1.16.0
 snowballstemmer==1.2.1
 statsd==3.2.1
 stevedore==3.3.0

openstack_dashboard/django_pyscss_fix/__init__.py

@@ -12,9 +12,21 @@
 
 import logging
 import os
+import sys
+
+import django
+import six
+import six.moves
 
 from django.conf import settings
 
+# Temporary workaround for a situation that django-pyscss depends on
+# a vendored version of six, django.utils.six which was dropped in Django 3.0.
+# TODO(amotoki): Drop the workaround once django-pyscss supports Django 3.0+.
+if django.VERSION[0] >= 3:
+    sys.modules['django.utils.six'] = six
+    sys.modules['django.utils.six.moves'] = six.moves
+
 scss_asset_root = os.path.join(settings.STATIC_ROOT, 'scss', 'assets')
 LOG = logging.getLogger(__name__)
 

openstack_dashboard/settings.py

@@ -151,9 +151,9 @@ INSTALLED_APPS = [
     'django.contrib.messages',
     'django.contrib.staticfiles',
     'django.contrib.humanize',
+    'openstack_dashboard.django_pyscss_fix',
     'django_pyscss',
     'debreach',
-    'openstack_dashboard.django_pyscss_fix',
     'compressor',
     'horizon',
     'openstack_auth',

requirements.txt

@@ -39,6 +39,7 @@ python-swiftclient>=3.2.0 # Apache-2.0
 pytz>=2013.6 # MIT
 PyYAML>=3.12 # MIT
 requests>=2.25.1 # Apache-2.0
+six>=1.16.0 # MIT
 semantic-version>=2.3.1 # BSD
 XStatic>=1.0.0 # MIT License
 XStatic-Angular>=1.5.8.0 # MIT License