Decision on file chooser error reporting

[Owen Taylor <otaylor redhat com>]

I spent some time looking through all uses of GtkFileChooser in
GNOME modules, and reading people's mails, and the decision I 
think we should take is:

 We should add gboolean returns to file chooser functions that 
 can fail, but we will not added GError * arguments to existing
 functions.
 
 In the future, we'll have the option of adding additional API
 to expose a GError * if there is demand.

Reasoning:

 * I think at this point we need to really prioritize sticking
   to the schedule. Is this "pandering" to the GNOME release
   requirements? To some extent, yes. GNOME is a very important
   user of GTK+. But even more so, it's pandering to everyone
   who believes in the schedules that we put out.

 * The two most convincing cases that were presented for wanting
   error indication did not require reporting a string to
   the user:

    - Doing a compound operation such as "change to a directory  
      and select a file"
    - Having a better-than-default fallback starting location
      for opening the dialog

 * Cases where a nice error message is desired are vanishingly
   rare; I don't think there is much harm if a generic
   "cannot change to directory %s" is used instead.

 * While adding a GError * is clearly more consistent with what
   we do elsewhere, it's not hugely more consistent. We do
   have other functions that return gboolean on failure 
   without a GError parameter.

 * There will be more API flaws discovered after we ship 2.4.0;
   this is inevitable. I believe that GtkFileChooser is a 
   very good API as it stands now; it makes what people want
   to do commonly easy, and what they want to do less commonly
   possible.

Consequences:

 - No applications will be affected. Adding gboolean return
   values to functions is according to our unwritten GTK+
   API/ABI standards, "sufficiently compatible".

 - Language bindings will have the option of rev'ing for this
   API change or not. If they want to expose the boolean return
   to their users, they will need to rev, but they will still
   work correctly without this change, and for most languages
   could compatibly add the boolean return later.

Regards,
						Owen