How to handle required plugins and dbus services for GNOME Programs?

[Mark H Weaver <mhw@netris.org>]

ludo@gnu.org (Ludovic Courtès) writes:

> Mark H Weaver <mhw@netris.org> skribis:
>
>> A few caveats: in order for totem to work properly, you must have
>> several other packages installed in your profile.  I'm not entirely sure
>> of the full set needed, but I guess it includes:
>>
>>   grilo
>>   grilo-plugins
>>   gstreamer
>>   gst-plugins-base
>>   gst-plugins-good
>>   dconf
>>
>> You will also need to set the GRL_PLUGIN_PATH and GST_PLUGIN_SYSTEM_PATH
>> environment variables as advised by "guix package --search-paths".
>
> I can imagine why the plugins package need to be in the profile, but I
> find the others more surprising.  Do you know what happens?  Are Grilo,
> GStreamer, and DConf dlopened, or is it just to get the right search
> path recommendation that they are needed?

Actually, it turns out that 'grilo' doesn't need to be in the profile,
although if you don't have it you won't get the search path
recommendation which is crucial for Totem to work properly.

'gstreamer' is a propagated-input of 'gst-plugins-base', so you don't
need to explicitly install it and I'm not sure what would happen if it
were removed.

'dconf' apparently needs to be in the profile for both GNOME Terminal
and Totem because of the session dbus service(s) it provides.  Without
it, modern GNOME programs behave quite badly.  They have no way to
access or change their own configuration settings, e.g. if you go into
their preferences, you see checkboxes that do not change their state
when clicked.

I'm not sure how best to deal with issues like this, and also with
things like grilo-plugins and gst-plugins-* that are needed for the
proper functioning of Totem.  Should we make them propagated-inputs?

Or perhaps they should be normal inputs and we should use a wrapper to
add those directories as suffixes to GRL_PLUGIN_PATH and
GST_PLUGIN_SYSTEM_PATH automatically?

What do you think?

      Mark