Drag & Drop on GTK + Maemo 5 (was: Re: [pymaemo] DnD on N900)

[I'm CC'ing maemo-developers as it is clearly not a Python specific
issue; see below for details]

On Wed, Jan 6, 2010 at 2:11 PM, Jeffrey Barish
<jeff_barish@earthlink.net> wrote:
> Well, it took a little more than a few days, but here is a test program.  It
> works on Ubuntu and N810, but not N900.

Well, I tested your example on Maemo and Ubuntu, and indeed the drag &
drop only worked on Ubuntu. Additionally, this error is shown on
console:

/tmp/dndtest.py:77: Warning: g_object_set_data_full: assertion
`G_IS_OBJECT (object)' failed
gtk.main()

So I went further and translated your example to C (please note I'm no
GTK expert, I'm only trying to help debugging the problem). And the
same behavior is presented: the drag does not work and this message is
shown on console:

dndtest[9349]: GLIB CRITICAL ** GLib-GObject - g_object_set_data_full:
assertion `G_IS_OBJECT (object)' failed

That means the problem is not related to Python or PyGTK at all, but
some GTK limitation/bug on Maemo 5.

The translated C example is attached.

Any ideas anyone? Regards,
--
Anderson Lizardo
OpenBossa Labs - INdT
Manaus - Brazil

El mié, 06-01-2010 a las 19:44 -0400, Anderson Lizardo escribió:
> [I'm CC'ing maemo-developers as it is clearly not a Python specific
> issue; see below for details]
>
> On Wed, Jan 6, 2010 at 2:11 PM, Jeffrey Barish
> <jeff_barish@earthlink.net> wrote:
> > Well, it took a little more than a few days, but here is a test program. It
> > works on Ubuntu and N810, but not N900.
>
> Well, I tested your example on Maemo and Ubuntu, and indeed the drag &
> drop only worked on Ubuntu. Additionally, this error is shown on
> console:
>
> /tmp/dndtest.py:77: Warning: g_object_set_data_full: assertion
> `G_IS_OBJECT (object)' failed
> gtk.main()
>
> So I went further and translated your example to C (please note I'm no
> GTK expert, I'm only trying to help debugging the problem). And the
> same behavior is presented: the drag does not work and this message is
> shown on console:
>
> dndtest[9349]: GLIB CRITICAL ** GLib-GObject - g_object_set_data_full:
> assertion `G_IS_OBJECT (object)' failed
>
> That means the problem is not related to Python or PyGTK at all, but
> some GTK limitation/bug on Maemo 5.

There is no drag 'n drop in Maemo GTK+. This has been deliberately
disabled.

A stacktrace on the critical warning would be useful to find out the
cause.

Claudio

On Thu, Jan 7, 2010 at 5:37 AM, Claudio Saavedra <csaavedra@igalia.com> wrote:
> There is no drag 'n drop in Maemo GTK+. This has been deliberately
> disabled.

I believe that pretty much answers Jeff's issue... Was this done for
Maemo 5 ? Because according to Jeff it used to work on the N810
(Diablo). I haven't tested it myself on N810 , though.

> A stacktrace on the critical warning would be useful to find out the
> cause.

How to get that stack trace (some glib/gtk function?) ? it does not
crash the application , so I think gdb cannot be used in this case.

Thanks,
--
Anderson Lizardo
OpenBossa Labs - INdT
Manaus - Brazil

El jue, 07-01-2010 a las 10:08 -0400, Anderson Lizardo escribió:
> On Thu, Jan 7, 2010 at 5:37 AM, Claudio Saavedra <csaavedra@igalia.com> wrote:
> > There is no drag 'n drop in Maemo GTK+. This has been deliberately
> > disabled.
>
> I believe that pretty much answers Jeff's issue... Was this done for
> Maemo 5 ? Because according to Jeff it used to work on the N810
> (Diablo). I haven't tested it myself on N810 , though.

Yes, only since Maemo 5.

>
> > A stacktrace on the critical warning would be useful to find out the
> > cause.
>
> How to get that stack trace (some glib/gtk function?) ? it does not
> crash the application , so I think gdb cannot be used in this case.

Set G_DEBUG=fatal-criticals. That will cause glib to abort on a critical
warning.

Claudio