Why isn't Gtk Filechooser Button selecting any file in my flatpak build? - gtk

Question

I have a file chooser button that triggers a change in the titlebar whenever a file is selected with it. And it seems to work fine in my non-flatpak build.
import gtk.Application : Application;
import gtk.ApplicationWindow : ApplicationWindow;
import gio.Application : GioApp = Application;
import gtkc.gtktypes : GApplicationFlags, FileChooserAction;
import gtk.FileChooserButton : FileChooserButton;
const string AppID = `org.github.flatfcbtest`;
int main(string[] args)
{
auto app = new App();
return app.run(args);
}
public class App : Application
{
public:
this(const string appID = AppID, const GApplicationFlags flags = GApplicationFlags.FLAGS_NONE)
{
super(appID, flags);
addOnActivate(delegate void(GioApp _) {
auto pw = new PrimaryWindow(this);
pw.showAll();
});
}
}
class PrimaryWindow : ApplicationWindow
{
this(Application app)
{
super(app);
setSizeRequest(500, 300);
auto fcb = new FileChooserButton(`Select file`, FileChooserAction.OPEN);
fcb.addOnFileSet(delegate void (FileChooserButton _) {
setTitle(`file set!`);
});
add(fcb);
}
}
(GtkD reference)
However in my flatpak builds, the file selected with the chooser button does not select anything and it keeps saying (None). However my titlebar is changes accordingly so I know that the signal was emitted by the file chooser button.
Here is my flatpak permissions list:
finish-args:
- --socket=fallback-x11
- --share=ipc
- --filesystem=host
- --device=all
- --socket=session-bus
What's causing this?

Answer 1

Typically if you're shipping a flatpak, you want to avoid --filesystem=host and just use GtkFileChooserNative instead. This class supports portals, allowing a user to select files the application does not have permission to access by itself.
This is a much better approach than giving the application full filesystem access. GtkFileChooserNative will still work in a non-flatpak application and you shouldn't notice any difference unless you're doing something fancy.
As for your question of why GtkFileChooser is not working with --filesystem=host however, I do not know.