Ticket #10868: 10868.settings-dict-copy.diff

django/db/backends/creation.py

@@ -320 +320 @@
             if verbosity >= 2:
                 test_db_repr = " ('%s')" % test_database_name
             print "Destroying test database for alias '%s'%s..." % (self.connection.alias, test_db_repr)
+        # Use a thread-local copy of the settings dict. That way we avoid
+        # modifying the original settings dict which would be shared between
+        # any potential child threads. This prevents the production database
+        # from being exposed to those potential child threads while the test
+        # database is being destroyed. Refs #10868.
+        self.connection.settings_dict = self.connection.settings_dict.copy()
         self.connection.settings_dict['NAME'] = old_database_name
-
         self._destroy_test_db(test_database_name, verbosity)
 
     def _destroy_test_db(self, test_database_name, verbosity):

django/test/simple.py

@@ -312 +312 @@
         return unittest.TextTestRunner(verbosity=self.verbosity, failfast=self.failfast).run(suite)
 
     def teardown_databases(self, old_config, **kwargs):
+        """
+        Clean up database connections and destroy test databases.
+
+        Note that we use thread-local copies of the connections' settings
+        dict references. That way we avoid modifying the original settings dict
+        references which would be shared between any potential child threads.
+        This prevents the production databases from being exposed to those
+        potential child threads while the test databases are being teared down.
+        Refs #10868.
+        """
         from django.db import connections
         old_names, mirrors = old_config
         # Point all the mirrors back to the originals
         for alias, old_name in mirrors:
+            connections[alias].settings_dict = connections[alias].settings_dict.copy()
             connections[alias].settings_dict['NAME'] = old_name
         # Destroy all the non-mirror databases
         for connection, old_name, destroy in old_names:
             if destroy:
                 connection.creation.destroy_test_db(old_name, self.verbosity)
             else:
+                connection.settings_dict = connection.settings_dict.copy()
                 connection.settings_dict['NAME'] = old_name
 
     def teardown_test_environment(self, **kwargs):