Bump django-compressor to 3.1, get rid of annoying warnings (#2459)

src/pretix/helpers/template_loaders.py

@@ -0,0 +1,36 @@
+#
+# This file is part of pretix (Community Edition).
+#
+# Copyright (C) 2014-2020 Raphael Michel and contributors
+# Copyright (C) 2020-2021 rami.io GmbH and contributors
+#
+# This program is free software: you can redistribute it and/or modify it under the terms of the GNU Affero General
+# Public License as published by the Free Software Foundation in version 3 of the License.
+#
+# ADDITIONAL TERMS APPLY: Pursuant to Section 7 of the GNU Affero General Public License, additional terms are
+# applicable granting you additional permissions and placing additional restrictions on your usage of this software.
+# Please refer to the pretix LICENSE file to obtain the full terms applicable to this work. If you did not receive
+# this file, see <https://pretix.eu/about/en/license>.
+#
+# This program 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 Affero General Public License for more
+# details.
+#
+# You should have received a copy of the GNU Affero General Public License along with this program.  If not, see
+# <https://www.gnu.org/licenses/>.
+#
+from django.template.loaders.app_directories import Loader
+from django.template.utils import get_app_template_dirs
+
+
+class AppLoader(Loader):
+
+    def get_dirs(self):
+        ds = get_app_template_dirs('templates')
+        ignore_patterns = {
+            # Ignore templates of plugins we don't actually use as they cause trouble during
+            # static file compression
+            '/django_filters/',
+            '/django_otp/',
+        }
+        return [d for d in ds if not any(p in str(d) for p in ignore_patterns)]