Fixed #23832 -- Added timezone aware Storage API.

New Storage.get_{accessed,created,modified}_time() methods convert the
naive time from now-deprecated {accessed,created_modified}_time()
methods into aware objects in UTC if USE_TZ=True.

django/contrib/staticfiles/management/commands/collectstatic.py

@@ -237,15 +237,14 @@ class Command(BaseCommand):
         if self.storage.exists(prefixed_path):
             try:
                 # When was the target file modified last time?
-                target_last_modified = \
-                    self.storage.modified_time(prefixed_path)
+                target_last_modified = self.storage.get_modified_time(prefixed_path)
             except (OSError, NotImplementedError, AttributeError):
-                # The storage doesn't support ``modified_time`` or failed
+                # The storage doesn't support get_modified_time() or failed
                 pass
             else:
                 try:
                     # When was the source file modified last time?
-                    source_last_modified = source_storage.modified_time(path)
+                    source_last_modified = source_storage.get_modified_time(path)
                 except (OSError, NotImplementedError, AttributeError):
                     pass
                 else:

django/core/files/storage.py

@@ -1,5 +1,6 @@
 import errno
 import os
+import warnings
 from datetime import datetime
 
 from django.conf import settings
@@ -7,9 +8,11 @@ from django.core.exceptions import SuspiciousFileOperation
 from django.core.files import File, locks
 from django.core.files.move import file_move_safe
 from django.core.signals import setting_changed
+from django.utils import timezone
 from django.utils._os import abspathu, safe_join
 from django.utils.crypto import get_random_string
 from django.utils.deconstruct import deconstructible
+from django.utils.deprecation import RemovedInDjango20Warning
 from django.utils.encoding import filepath_to_uri, force_text
 from django.utils.functional import LazyObject, cached_property
 from django.utils.module_loading import import_string
@@ -140,24 +143,101 @@ class Storage(object):
     def accessed_time(self, name):
         """
         Returns the last accessed time (as datetime object) of the file
-        specified by name.
+        specified by name. Deprecated: use get_accessed_time() instead.
         """
+        warnings.warn(
+            'Storage.accessed_time() is deprecated in favor of get_accessed_time().',
+            RemovedInDjango20Warning,
+            stacklevel=2,
+        )
         raise NotImplementedError('subclasses of Storage must provide an accessed_time() method')
 
     def created_time(self, name):
         """
         Returns the creation time (as datetime object) of the file
-        specified by name.
+        specified by name. Deprecated: use get_created_time() instead.
         """
+        warnings.warn(
+            'Storage.created_time() is deprecated in favor of get_created_time().',
+            RemovedInDjango20Warning,
+            stacklevel=2,
+        )
         raise NotImplementedError('subclasses of Storage must provide a created_time() method')
 
     def modified_time(self, name):
         """
         Returns the last modified time (as datetime object) of the file
-        specified by name.
+        specified by name. Deprecated: use get_modified_time() instead.
         """
+        warnings.warn(
+            'Storage.modified_time() is deprecated in favor of get_modified_time().',
+            RemovedInDjango20Warning,
+            stacklevel=2,
+        )
         raise NotImplementedError('subclasses of Storage must provide a modified_time() method')
 
+    def get_accessed_time(self, name):
+        """
+        Return the last accessed time (as a datetime) of the file specified by
+        name. The datetime will be timezone-aware if USE_TZ=True.
+        """
+        # At the end of the deprecation:
+        # raise NotImplementedError('subclasses of Storage must provide a get_accessed_time() method')
+        warnings.warn(
+            'Storage.accessed_time() is deprecated. '
+            'Storage backends should implement get_accessed_time().',
+            RemovedInDjango20Warning,
+            stacklevel=2,
+        )
+        dt = self.accessed_time(name)
+        return _possibly_make_aware(dt)
+
+    def get_created_time(self, name):
+        """
+        Return the creation time (as a datetime) of the file specified by name.
+        The datetime will be timezone-aware if USE_TZ=True.
+        """
+        # At the end of the deprecation:
+        # raise NotImplementedError('subclasses of Storage must provide a get_created_time() method')
+        warnings.warn(
+            'Storage.created_time() is deprecated. '
+            'Storage backends should implement get_created_time().',
+            RemovedInDjango20Warning,
+            stacklevel=2,
+        )
+        dt = self.created_time(name)
+        return _possibly_make_aware(dt)
+
+    def get_modified_time(self, name):
+        """
+        Return the last modified time (as a datetime) of the file specified by
+        name. The datetime will be timezone-aware if USE_TZ=True.
+        """
+        # At the end of the deprecation:
+        # raise NotImplementedError('subclasses of Storage must provide a get_modified_time() method')
+        warnings.warn(
+            'Storage.modified_time() is deprecated. '
+            'Storage backends should implement get_modified_time().',
+            RemovedInDjango20Warning,
+            stacklevel=2,
+        )
+        dt = self.modified_time(name)
+        return _possibly_make_aware(dt)
+
+
+def _possibly_make_aware(dt):
+    """
+    Convert a datetime object in the local timezone to aware
+    in UTC, if USE_TZ is True.
+    """
+    # This function is only needed to help with the deprecations above and can
+    # be removed in Django 2.0, RemovedInDjango20Warning.
+    if settings.USE_TZ:
+        tz = timezone.get_default_timezone()
+        return timezone.make_aware(dt, tz).astimezone(timezone.utc)
+    else:
+        return dt
+
 
 @deconstructible
 class FileSystemStorage(Storage):
@@ -328,14 +408,52 @@ class FileSystemStorage(Storage):
         return urljoin(self.base_url, filepath_to_uri(name))
 
     def accessed_time(self, name):
+        warnings.warn(
+            'FileSystemStorage.accessed_time() is deprecated in favor of '
+            'get_accessed_time().',
+            RemovedInDjango20Warning,
+            stacklevel=2,
+        )
         return datetime.fromtimestamp(os.path.getatime(self.path(name)))
 
     def created_time(self, name):
+        warnings.warn(
+            'FileSystemStorage.created_time() is deprecated in favor of '
+            'get_created_time().',
+            RemovedInDjango20Warning,
+            stacklevel=2,
+        )
         return datetime.fromtimestamp(os.path.getctime(self.path(name)))
 
     def modified_time(self, name):
+        warnings.warn(
+            'FileSystemStorage.modified_time() is deprecated in favor of '
+            'get_modified_time().',
+            RemovedInDjango20Warning,
+            stacklevel=2,
+        )
         return datetime.fromtimestamp(os.path.getmtime(self.path(name)))
 
+    def _datetime_from_timestamp(self, ts):
+        """
+        If timezone support is enabled, make an aware datetime object in UTC;
+        otherwise make a naive one in the local timezone.
+        """
+        if settings.USE_TZ:
+            # Safe to use .replace() because UTC doesn't have DST
+            return datetime.utcfromtimestamp(ts).replace(tzinfo=timezone.utc)
+        else:
+            return datetime.fromtimestamp(ts)
+
+    def get_accessed_time(self, name):
+        return self._datetime_from_timestamp(os.path.getatime(self.path(name)))
+
+    def get_created_time(self, name):
+        return self._datetime_from_timestamp(os.path.getctime(self.path(name)))
+
+    def get_modified_time(self, name):
+        return self._datetime_from_timestamp(os.path.getmtime(self.path(name)))
+
 
 def get_storage_class(import_path=None):
     return import_string(import_path or settings.DEFAULT_FILE_STORAGE)