Confirming.

Hint: if you don't need these signals to interface with C code, only from python to python, you can use the type 'object' to allow any python object as signal argument (in C land it is a boxed type).

Created attachment 71270 [details] [review]
pygobject-marshal-gvalue-gvalue.patch

Suggested patch.

Workaround is to use these functions in embedding code:

static PyObject *
pyg_value_g_value_as_pyobject (const GValue *value)
{
	return pyg_value_as_pyobject((GValue *)g_value_get_boxed(value), FALSE);
}

static int
pyg_value_g_value_from_pyobject (GValue *value, PyObject *obj)
{
	GType type;
	GValue obj_value = { 0, };
	
	type = pyg_type_from_object((PyObject *) obj->ob_type);
	if (! type) {
		PyErr_Clear();
		return -1;
	}
	g_value_init(&obj_value, type);
	if (pyg_value_from_pyobject(&obj_value, obj) == -1) {
		g_value_unset(&obj_value);
		return -1;
	}
	g_value_set_boxed(value, &obj_value);
	g_value_unset(&obj_value);
	return 0;
}

...

	init_pygobject ();

	pyg_register_gtype_custom (G_TYPE_VALUE, pyg_value_g_value_as_pyobject, pyg_value_g_value_from_pyobject);

(In reply to comment #2)
> Created an attachment (id=71270) [edit]
> pygobject-marshal-gvalue-gvalue.patch
> 
> Suggested patch.
> 

In general the patch looks good. But it's missing a test, do you think you can write a simple testcase demostrating this bug?

Created attachment 91313 [details] [review]
TestCase

Created attachment 91314 [details] [review]
Updated path to be commited in trunk

Created attachment 91315 [details] [review]
Changelog

This problem has been fixed in the development version. The fix will be available in the next major software release. Thank you for your bug report.