Fixed #23524 -- Allowed DATABASES['TIME_ZONE'] option on PostgreSQL.

django/db/backends/base/base.py

@@ -124,11 +124,11 @@ class BaseDatabaseWrapper:
 
         When the database backend supports time zones, it doesn't matter which
         time zone Django uses, as long as aware datetimes are used everywhere.
-        For simplicity, Django selects UTC.
+        Other users connecting to the database can choose their own time zone.
 
         When the database backend doesn't support time zones, the time zone
-        Django uses can be selected with the TIME_ZONE configuration option, so
-        it can match what other users of the database expect.
+        Django uses may be constrained by the requirements of other users of
+        the database.
         """
         if not settings.USE_TZ:
             return None
@@ -205,15 +205,11 @@ class BaseDatabaseWrapper:
         self.run_on_commit = []
 
     def check_settings(self):
-        if self.settings_dict['TIME_ZONE'] is not None:
-            if not settings.USE_TZ:
-                raise ImproperlyConfigured(
-                    "Connection '%s' cannot set TIME_ZONE because USE_TZ is "
-                    "False." % self.alias)
-            elif self.features.supports_timezones:
-                raise ImproperlyConfigured(
-                    "Connection '%s' cannot set TIME_ZONE because its engine "
-                    "handles time zones conversions natively." % self.alias)
+        if self.settings_dict['TIME_ZONE'] is not None and not settings.USE_TZ:
+            raise ImproperlyConfigured(
+                "Connection '%s' cannot set TIME_ZONE because USE_TZ is False."
+                % self.alias
+            )
 
     @async_unsafe
     def ensure_connection(self):

django/db/backends/postgresql/base.py

@@ -47,7 +47,6 @@ from .features import DatabaseFeatures                      # NOQA isort:skip
 from .introspection import DatabaseIntrospection            # NOQA isort:skip
 from .operations import DatabaseOperations                  # NOQA isort:skip
 from .schema import DatabaseSchemaEditor                    # NOQA isort:skip
-from .utils import utc_tzinfo_factory                       # NOQA isort:skip
 
 psycopg2.extensions.register_adapter(SafeString, psycopg2.extensions.QuotedString)
 psycopg2.extras.register_uuid()
@@ -231,9 +230,12 @@ class DatabaseWrapper(BaseDatabaseWrapper):
             cursor = self.connection.cursor(name, scrollable=False, withhold=self.connection.autocommit)
         else:
             cursor = self.connection.cursor()
-        cursor.tzinfo_factory = utc_tzinfo_factory if settings.USE_TZ else None
+        cursor.tzinfo_factory = self.tzinfo_factory if settings.USE_TZ else None
         return cursor
 
+    def tzinfo_factory(self, offset):
+        return self.timezone
+
     @async_unsafe
     def chunked_cursor(self):
         self._named_cursor_idx += 1

django/db/backends/postgresql/utils.py

@@ -1,7 +0,0 @@
-from django.utils.timezone import utc
-
-
-def utc_tzinfo_factory(offset):
-    if offset != 0:
-        raise AssertionError("database connection isn't set to UTC")
-    return utc