Fixed explicit connection.cursor(cursor_factory=None)

Fixes issue #210.

NEWS

@@ -26,6 +26,8 @@ What's new in psycopg 2.4.7
     happens for TCP connections instead (:ticket:`#196`).
   - Fixed overflow opening a lobject with an oid not fitting in a signed int
     (:ticket:`#203`).
+  - Fixed handling of explicit default ``cursor_factory=None`` in
+    `connection.cursor()` (:ticket:`#210`).
   - Mark the connection closed if found broken on `poll()`.
   - Fixed possible segfault in named cursors creation.
   - Fixed debug build on Windows, thanks to James Emerton.

psycopg/connection_type.c

@@ -54,7 +54,7 @@ psyco_conn_cursor(connectionObject *self, PyObject *args, PyObject *kwargs)
 {
     PyObject *obj;
     PyObject *name = Py_None;
-    PyObject *factory = (PyObject *)&cursorType;
+    PyObject *factory = Py_None;
     PyObject *withhold = Py_False;
 
     static char *kwlist[] = {"name", "cursor_factory", "withhold", NULL};
@@ -72,6 +72,10 @@ psyco_conn_cursor(connectionObject *self, PyObject *args, PyObject *kwargs)
 
     EXC_IF_CONN_CLOSED(self);
 
+    if (factory == Py_None) {
+        factory = (PyObject *)&cursorType;
+    }
+
     if (self->status != CONN_STATUS_READY &&
         self->status != CONN_STATUS_BEGIN &&
         self->status != CONN_STATUS_PREPARED) {

tests/test_connection.py

@@ -218,6 +218,13 @@ class ConnectionTests(unittest.TestCase):
 
         self.assert_(not notices, "%d notices raised" % len(notices))
 
+    def test_cursor_factory_none(self):
+        # issue #210
+        conn = psycopg2.connect(dsn)
+        cur = conn.cursor(cursor_factory=None)
+        self.assertEqual(type(cur), psycopg2.extensions.cursor)
+        conn.close()
+
     def test_failed_init_status(self):
         class SubConnection(psycopg2.extensions.connection):
             def __init__(self, dsn):