That's not missing, Vala uses user_data automatically. Can you please provide some example usage?

(In reply to comment #1)
> That's not missing, Vala uses user_data automatically. Can you please provide
> some example usage?

No auto. I have a build break. Is something different between vala 0.24 and newer?

src/ChannelFactory.vala:277.29-277.91: error: 1 extra arguments for `bool Gst.Iterator.find_custom (GLib.CompareFunc func, out GLib.Value elem)'
                        if (it.find_custom ((GLib.CompareFunc)find_element, out elem, sink)) {
                            ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

GStreamer annotates this as (closure) for a GCompareFunc, but GCompareFunc doesn't take a closure parameters, so that should be removed.

What we should probably do is use GLib.SearchFunc instead, just not sure what the generic parameters should be.

the same effect

src/ChannelFactory.vala:277.45-277.74: error: Argument 1: Cannot convert from `GLib.CompareFunc' to `GLib.SearchFunc'
                        if (it.find_custom ((GLib.CompareFunc)find_element, out elem, sink)) {
                                            ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

src/ChannelFactory.vala:277.29-277.90: error: 1 extra arguments for `bool Gst.Iterator.find_custom (GLib.SearchFunc func, out GLib.Value elem)'
                        if (it.find_custom ((GLib.SearchFunc)find_element, out elem, sink)) {

No, the VAPI should be changed to something like

   public bool find_custom<A,B> (GLib.SearchFunc<A,B> func, out GLib.Value elem, B data);

Optimally, though, we should make Iterator a generic so that one of those type arguments is filled in automatically:

  public class Iterator<T> {
    public void find_custom<N> (GLib.SearchFunc<T,N> func, out GLib.Value elem, N data);
  }

I'll take a look at it soon.  I want to start going through all the gstreamer vapis and clean them up.

The patch in bug #730983 includes a fix for this.

Great. It looks good. Build works.

(In reply to comment #5)

>                         if (it.find_custom ((GLib.SearchFunc)find_element, out
> elem, sink)) {

no cast needed anymore.

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.