Fixed segfault in large object close.

Check that the connection is not closed/faulty before attempting lo_close.

NEWS-2.3

@@ -7,12 +7,14 @@ What's new in psycopg 2.3.3
     into Python tuples/namedtuples.
   - The build script refuses to guess values if pg_config is not found.
   - Connections and cursors are weakly referenceable.
-  - Fixed several reference leaks in less common code paths.
 
 * Bug fixes:
 
   - Fixed adaptation of None in composite types (ticket #26). Bug report by
     Karsten Hilbert.
+  - Fixed several reference leaks in less common code paths.
+  - Fixed segfault when a large object is closed and its connection no more
+    available.
 
 
 What's new in psycopg 2.3.2

psycopg/lobject_int.c

@@ -129,6 +129,21 @@ lobject_close_locked(lobjectObject *self, char **error)
 {
     int retvalue;
 
+    Dprintf("lobject_close_locked: conn->closed %ld", self->conn->closed);
+    switch (self->conn->closed) {
+    case 0:
+        /* Connection is open, go ahead */
+        break;
+    case 1:
+        /* Connection is closed, return a success */
+        return 0;
+        break;
+    default:
+        PyErr_SetString(OperationalError, "the connection is broken");
+        return -1;
+        break;
+    }
+
     if (self->conn->isolation_level == ISOLATION_LEVEL_AUTOCOMMIT ||
         self->conn->mark != self->mark ||
         self->fd == -1)

tests/test_lobject.py

@@ -60,6 +60,10 @@ class LargeObjectMixin(object):
     def tearDown(self):
         if self.tmpdir:
             shutil.rmtree(self.tmpdir, ignore_errors=True)
+
+        if self.conn.closed:
+            return
+
         if self.lo_oid is not None:
             self.conn.rollback()
             try:
@@ -106,6 +110,11 @@ class LargeObjectTests(LargeObjectMixin, unittest.TestCase):
         self.assertEqual(lo2.oid, lo.oid)
         self.assertEqual(lo2.closed, True)
 
+    def test_close_connection_gone(self):
+        lo = self.conn.lobject()
+        self.conn.close()
+        lo.close()
+
     def test_create_with_oid(self):
         # Create and delete a large object to get an unused Oid.
         lo = self.conn.lobject()