--- a/app/django/db/__init__.py	Tue Oct 14 12:36:55 2008 +0000
+++ b/app/django/db/__init__.py	Tue Oct 14 16:00:59 2008 +0000
@@ -2,7 +2,6 @@
 from django.conf import settings
 from django.core import signals
 from django.core.exceptions import ImproperlyConfigured
-from django.dispatch import dispatcher
 from django.utils.functional import curry
 
 __all__ = ('backend', 'connection', 'DatabaseError', 'IntegrityError')
@@ -15,42 +14,27 @@
     # backends that ships with Django, so look there first.
     _import_path = 'django.db.backends.'
     backend = __import__('%s%s.base' % (_import_path, settings.DATABASE_ENGINE), {}, {}, [''])
-    creation = __import__('%s%s.creation' % (_import_path, settings.DATABASE_ENGINE), {}, {}, [''])
 except ImportError, e:
     # If the import failed, we might be looking for a database backend
     # distributed external to Django. So we'll try that next.
     try:
         _import_path = ''
         backend = __import__('%s.base' % settings.DATABASE_ENGINE, {}, {}, [''])
-        creation = __import__('%s.creation' % settings.DATABASE_ENGINE, {}, {}, [''])
     except ImportError, e_user:
         # The database backend wasn't found. Display a helpful error message
         # listing all possible (built-in) database backends.
         backend_dir = os.path.join(__path__[0], 'backends')
-        available_backends = [f for f in os.listdir(backend_dir) if not f.startswith('_') and not f.startswith('.') and not f.endswith('.py') and not f.endswith('.pyc')]
+        try:
+            available_backends = [f for f in os.listdir(backend_dir) if not f.startswith('_') and not f.startswith('.') and not f.endswith('.py') and not f.endswith('.pyc')]
+        except EnvironmentError:
+            available_backends = []
         available_backends.sort()
         if settings.DATABASE_ENGINE not in available_backends:
-            raise ImproperlyConfigured, "%r isn't an available database backend. Available options are: %s" % \
-                (settings.DATABASE_ENGINE, ", ".join(map(repr, available_backends)))
+            raise ImproperlyConfigured, "%r isn't an available database backend. Available options are: %s\nError was: %s" % \
+                (settings.DATABASE_ENGINE, ", ".join(map(repr, available_backends)), e_user)
         else:
             raise # If there's some other error, this must be an error in Django itself.
 
-def _import_database_module(import_path='', module_name=''):
-    """Lazily import a database module when requested."""
-    return __import__('%s%s.%s' % (import_path, settings.DATABASE_ENGINE, module_name), {}, {}, [''])
-
-# We don't want to import the introspect module unless someone asks for it, so
-# lazily load it on demmand.
-get_introspection_module = curry(_import_database_module, _import_path, 'introspection')
-
-def get_creation_module():
-    return creation
-
-# We want runshell() to work the same way, but we have to treat it a
-# little differently (since it just runs instead of returning a module like
-# the above) and wrap the lazily-loaded runshell() method.
-runshell = lambda: _import_database_module(_import_path, "client").runshell()
-
 # Convenient aliases for backend bits.
 connection = backend.DatabaseWrapper(**settings.DATABASE_OPTIONS)
 DatabaseError = backend.DatabaseError
@@ -58,17 +42,22 @@
 
 # Register an event that closes the database connection
 # when a Django request is finished.
-dispatcher.connect(connection.close, signal=signals.request_finished)
+def close_connection(**kwargs):
+    connection.close()
+signals.request_finished.connect(close_connection)
 
 # Register an event that resets connection.queries
 # when a Django request is started.
-def reset_queries():
+def reset_queries(**kwargs):
     connection.queries = []
-dispatcher.connect(reset_queries, signal=signals.request_started)
+signals.request_started.connect(reset_queries)
 
 # Register an event that rolls back the connection
 # when a Django request has an exception.
-def _rollback_on_exception():
+def _rollback_on_exception(**kwargs):
     from django.db import transaction
-    transaction.rollback_unless_managed()
-dispatcher.connect(_rollback_on_exception, signal=signals.got_request_exception)
+    try:
+        transaction.rollback_unless_managed()
+    except DatabaseError:
+        pass
+signals.got_request_exception.connect(_rollback_on_exception)