OverwriteStorage was removed from django-storages, so pull it into edx-platform (for now?)

common/djangoapps/third_party_auth/tests/testutil.py

@@ -18,7 +18,7 @@ from django.contrib.sites.models import Site
 from mako.template import Template
 from provider import constants
 from provider.oauth2.models import Client as OAuth2Client
-from storages.backends.overwrite import OverwriteStorage
+from openedx.core.storage import OverwriteStorage
 
 from third_party_auth.models import (
     LTIProviderConfig,

lms/envs/bok_choy.py

@@ -245,7 +245,7 @@ SECRET_KEY = "very_secret_bok_choy_key"
 
 # Set dummy values for profile image settings.
 PROFILE_IMAGE_BACKEND = {
-    'class': 'storages.backends.overwrite.OverwriteStorage',
+    'class': 'openedx.core.storage.OverwriteStorage',
     'options': {
         'location': os.path.join(MEDIA_ROOT, 'profile-images/'),
         'base_url': os.path.join(MEDIA_URL, 'profile-images/'),

lms/envs/common.py

@@ -3318,7 +3318,7 @@ MODULESTORE_FIELD_OVERRIDE_PROVIDERS = ('openedx.features.content_type_gating.fi
 # occurring when a user uploads a new profile image to replace an
 # earlier one (the file will temporarily be deleted).
 PROFILE_IMAGE_BACKEND = {
-    'class': 'storages.backends.overwrite.OverwriteStorage',
+    'class': 'openedx.core.storage.OverwriteStorage',
     'options': {
         'location': os.path.join(MEDIA_ROOT, 'profile-images/'),
         'base_url': os.path.join(MEDIA_URL, 'profile-images/'),

lms/envs/lms.yml

@@ -469,7 +469,7 @@ PROCTORING_BACKENDS:
     'null': {}
 PROCTORING_SETTINGS: {}
 PROFILE_IMAGE_BACKEND:
-    class: storages.backends.overwrite.OverwriteStorage
+    class: openedx.core.storage.OverwriteStorage
     options:
         base_url: /media/profile-images/
         location: /edx/var/edxapp/media/profile-images/

lms/envs/test.py

@@ -475,7 +475,7 @@ FEATURES['CUSTOM_COURSES_EDX'] = True
 
 # Set dummy values for profile image settings.
 PROFILE_IMAGE_BACKEND = {
-    'class': 'storages.backends.overwrite.OverwriteStorage',
+    'class': 'openedx.core.storage.OverwriteStorage',
     'options': {
         'location': MEDIA_ROOT,
         'base_url': 'http://example-storage.com/profile-images/',

openedx/core/storage.py

@@ -4,7 +4,8 @@ Django storage backends for Open edX.
 from __future__ import absolute_import
 
 from django.contrib.staticfiles.storage import StaticFilesStorage
-from django.core.files.storage import get_storage_class
+from django.core.files.storage import get_storage_class, FileSystemStorage
+from django.utils.deconstruct import deconstructible
 from django.utils.lru_cache import lru_cache
 from pipeline.storage import NonPackagingMixin, PipelineCachedStorage
 from require.storage import OptimizedFilesMixin
@@ -90,6 +91,28 @@ class S3ReportStorage(S3BotoStorage):  # pylint: disable=abstract-method
         super(S3ReportStorage, self).__init__(acl=acl, bucket=bucket, **settings)
 
 
+@deconstructible
+class OverwriteStorage(FileSystemStorage):
+    """
+    FileSystemStorage subclass which automatically overwrites any previous
+    file with the same name; used in test runs to avoid test file proliferation.
+    Copied from django-storages when this class was removed in version 1.6.
+
+    Comes from http://www.djangosnippets.org/snippets/976/
+    (even if it already exists in S3Storage for ages)
+    See also Django #4339, which might add this functionality to core.
+    """
+
+    def get_available_name(self, name, max_length=None):
+        """
+        Returns a filename that's free on the target storage system, and
+        available for new content to be written to.
+        """
+        if self.exists(name):
+            self.delete(name)
+        return name
+
+
 @lru_cache()
 def get_storage(storage_class=None, **kwargs):
     """