From e11d0d39ec3c9e3906f50d74d15eed1c01fa5fea Mon Sep 17 00:00:00 2001
From: Daniele Varrazzo <daniele.varrazzo@gmail.com>
Date: Wed, 27 Nov 2013 12:42:57 +0000
Subject: [PATCH] Check connection type in lobject init

Fixes ticket #187.
---
 NEWS                   |  2 ++
 psycopg/lobject_type.c | 17 ++++++++++-------
 tests/test_lobject.py  |  4 ++++
 3 files changed, 16 insertions(+), 7 deletions(-)

diff --git a/NEWS b/NEWS
index 14b50512..ab2b3a5a 100644
--- a/NEWS
+++ b/NEWS
@@ -8,6 +8,8 @@ What's new in psycopg 2.5.2
   (:ticket:`#170`).
 - Meaningful connection errors report a meaningful message, thanks to
   Alexey Borzenkov (:ticket:`#173`).
+- Manually creating `lobject` with the wrong parameter doesn't segfault
+  (:ticket:`#187`).
 
 
 What's new in psycopg 2.5.1
diff --git a/psycopg/lobject_type.c b/psycopg/lobject_type.c
index fee11c45..d5051570 100644
--- a/psycopg/lobject_type.c
+++ b/psycopg/lobject_type.c
@@ -355,10 +355,12 @@ lobject_dealloc(PyObject* obj)
 {
     lobjectObject *self = (lobjectObject *)obj;
 
-    if (lobject_close(self) < 0)
-        PyErr_Print();
-    Py_XDECREF((PyObject*)self->conn);
-    PyMem_Free(self->smode);
+    if (self->conn) {   /* if not, init failed */
+        if (lobject_close(self) < 0)
+            PyErr_Print();
+        Py_XDECREF((PyObject*)self->conn);
+        PyMem_Free(self->smode);
+    }
 
     Dprintf("lobject_dealloc: deleted lobject object at %p, refcnt = "
             FORMAT_CODE_PY_SSIZE_T, obj, Py_REFCNT(obj));
@@ -372,10 +374,11 @@ lobject_init(PyObject *obj, PyObject *args, PyObject *kwds)
     int oid = (int)InvalidOid, new_oid = (int)InvalidOid;
     const char *smode = "";
     const char *new_file = NULL;
-    PyObject *conn;
+    PyObject *conn = NULL;
 
-    if (!PyArg_ParseTuple(args, "O|iziz",
-         &conn, &oid, &smode, &new_oid, &new_file))
+    if (!PyArg_ParseTuple(args, "O!|iziz",
+         &connectionType, &conn,
+         &oid, &smode, &new_oid, &new_file))
         return -1;
 
     return lobject_setup((lobjectObject *)obj,
diff --git a/tests/test_lobject.py b/tests/test_lobject.py
index 83e9e73c..e62e0d85 100755
--- a/tests/test_lobject.py
+++ b/tests/test_lobject.py
@@ -77,6 +77,10 @@ class LargeObjectTests(LargeObjectTestCase):
         self.assertNotEqual(lo, None)
         self.assertEqual(lo.mode[0], "w")
 
+    def test_connection_needed(self):
+        self.assertRaises(TypeError,
+            psycopg2.extensions.lobject, [])
+
     def test_open_non_existent(self):
         # By creating then removing a large object, we get an Oid that
         # should be unused.