Re: [g-a-devel] Problems with Orca and Accerciser calling GConf client and at-spi2

[Mike Gorse <mgorse alum wpi edu>]

Hi all,

So we had pyatspi2 importing gconf, using GConf from gi.repository (the 
new pygi-based binding) if available, to check whether the at-spi-corba 
key is enabled.  (If it could not find a GI typelib for gconf, then it 
would fall back to trying the old pygtk-based binding.  If pyatspi2 was 
built with --enable-relocate, then all of this code would not be invoked. 
So this is why some people have been seeing the traceback and some 
haven't.)

Anyway, I just pushed a change to pyatspi2 to make it call gconftool-2 
rather than trying to import gconf.  This fixes the issue for me, although 
it might add 10-20 ms to the startup time, so feel free to test.

I'm not sure if we should even still be using a gconf key for this.  We 
may want to migrate the key to gsettings.  The only downside that I see to 
this is that it leaves open the question of what to do if at-spi-corba is 
built with --disable-relocate.  My inclination would be to leave things as 
they are in that case, continuing to let at-spi-corba use a gconf key, 
since AT-SPI-CORBA being the default would correlate with a GNOME 2 setup, 
but this would mean that the behavior in the two cases is no longer 
parallel.

Thanks,
-Mike

On Fri, 21 Jan 2011, Piñeiro wrote:

> Some people during the last weeks (me included) can't use accerciser,
> as it crashes with this error:
>
> Traceback (most recent call last):
>  File "/opt/gnome3/bin/accerciser", line 51, in <module>
>    accerciser.main()
>  File "/opt/gnome3/lib/python2.7/site-packages/accerciser/__init__.py", line 34, in main
>    from accerciser import Main
>  File "/opt/gnome3/lib/python2.7/site-packages/accerciser/accerciser.py", line 27, in <module>
>    from accessible_treeview import *
>  File "/opt/gnome3/lib/python2.7/site-packages/accerciser/accessible_treeview.py", line 21, in <module>
>    from node import Node
>  File "/opt/gnome3/lib/python2.7/site-packages/accerciser/node.py", line 28, in <module>
>    cl.get_string('/apps/accerciser/highlight_border') or '#ff0000ff')
>  File "/opt/gnome3/lib/python2.7/site-packages/gi/types.py", line 40, in function
>    return info.invoke(*args)
> TypeError: instance: Must be GConf.Client, not Client
>
> I also have this problem on Orca, but as it normally uses
> 'try-except', it keeps working, although printing the same error (and
> probably explaining why orca constantly goes to the command line).
>
> What I understood from this traceback is that for any reason, it is
> trying to use the new pygobject bindings to use gconf, but fails as
> accerciser is not migrated yet.
>
> But, it worked using this code on the command line:
>
>   >>> import gconf
>   >>> gconf.client_get_default().get_string('/apps/accerciser/highlight_border')
>   '#ff0000ff'
>
> So I supposed that importing other module was causing the use of
> pygobject introspection bindings. And I found that package:
>
>   >>> import pyatspi
>   >>> import gconf
>   >>> gconf.client_get_default().get_string('/apps/accerciser/highlight_border')
>   Traceback (most recent call last):
>     File "<stdin>", line 1, in <module>
>     File "/opt/gnome3/lib/python2.7/site-packages/gi/types.py", line 40, in function
>       return info.invoke(*args)
>   TypeError: instance: Must be GConf.Client, not Client
>
> As problably you know, recently Mike Gorse started to use gobject
> introspection for the at-spi2 python bindings, in his work related to
> improve the performance.
>
> So I guess that this is a problem caused for a mixed "old python
> bindings-new python bindings" environment. No idea why this is still
> working for other people. But stay tuned, as this could start to
> happen to you soon.
>
> One idea would be try to move the import order on accerciser, but as
> far as I see, "import pyatspi" would be required during most of the
> running time of accerciser, and "import gconf" just when you required
> a property value.
>
> So my question (please, if there are a best ml, point that, AFAIK,
> there isn't a gobject introspection mailing list):
>
>  * There is a way to force to "load the old python bindings" when you
>    call "import gconf" ?
>
> Of course, the workaroud would be go back to older pyatspi2 (so
> at-spi2-core and at-spi2-atk) versions (not ideal, as the
> accessibility community should test at-spi2).
>
> BTW, I didn't report this as a bug, because I guess that the "do the
> right thing" solution here would be do the gobject introspection
> migration on accerciser [2]. Anyway, taking into account Eitan
> comments related to Caribou [3], this doesn't seem a easy task.
>
> BR
>
> [1] http://live.gnome.org/Accessibility/GNOME3#pyatspi2_.28D-Bus.29
> [2] http://live.gnome.org/GnomeGoals/AddGObjectIntrospectionSupport
> [3] http://monotonous.org/2011/01/07/biannual-update/
>
> ===
> API (apinheiro igalia com)
>
>
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