[pygobject] Respect transfer-type when demarshalling GErrors

[Tomeu Vizoso <tomeuv src gnome org>]

commit d69e5b3c7bdb9113382fd125c256b12bff4c24d2
Author: Alberto Mardegan <mardy users sourceforge net>
Date:   Mon Jan 23 12:37:26 2012 +0200

    Respect transfer-type when demarshalling GErrors
    
    The marshaller previously ignored "transfer full" on GError* arguments, causing
    crashes due to double-freeing them. This causes the testCallbackUserdata() test
    case to crash after the previous GError/GHashTable marshalling fix.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=666270

 gi/pygi-argument.c |   12 +++++++++++-
 1 files changed, 11 insertions(+), 1 deletions(-)
---
diff --git a/gi/pygi-argument.c b/gi/pygi-argument.c
index bf2ed8a..9d99c35 100644
--- a/gi/pygi-argument.c
+++ b/gi/pygi-argument.c
@@ -1785,7 +1785,16 @@ _pygi_argument_to_object (GIArgument  *arg,
             break;
         }
         case GI_TYPE_TAG_ERROR:
-            if (pyglib_error_check ( (GError **) &arg->v_pointer)) {
+        {
+            GError *error = (GError *) arg->v_pointer;
+            if (error != NULL && transfer == GI_TRANSFER_NOTHING) {
+                /* If we have not been transferred the ownership we must copy
+                 * the error, because pyglib_error_check() is going to free it.
+                 */
+                error = g_error_copy (error);
+            }
+
+            if (pyglib_error_check (&error)) {
                 PyObject *err_type;
                 PyObject *err_value;
                 PyObject *err_trace;
@@ -1798,6 +1807,7 @@ _pygi_argument_to_object (GIArgument  *arg,
                 Py_INCREF (object);
                 break;
             }
+        }
     }
 
     return object;