Exported D-Bus services not seen on installation

[owtaylor]

Testing with F30, dbus-broker:

$ flatpak install flathub org.gnome.Maps
$ gapplication launch org.gnome.Maps
error sending Activate message to application: GDBus.Error:org.freedesktop.DBus.Error.ServiceUnknown: The name is not activatable
$ sudo sh -c 'date > /var/lib/flatpak/exports/share/dbus-1/services/.changed'
$ gapplication launch org.gnome.Maps
<launches>

The problem here is that dbus-broker (and also dbus-daemon as far as I can tell from reading the code) watch service directories with:

        r = inotify_add_watch(dw->inotify_fd,
                              path,
                              IN_CLOSE_WRITE | IN_DELETE
                                             | IN_MOVED_TO
                                             | IN_MOVED_FROM);

Which does not notice new symlinks in a directory, since that's IN_CREATE. I'll file an issue against dbus-broker - whether they'll fix it or not may depend on how serious they are with bug-for-bug compatibility with dbus-daemon. It might make sense to put a workaround in Flatpak in any case.

[alexlarsson]

I think we should just create the symlink with some temp name and move it into place. Should make it get the right event.

[alexlarsson]

I believe that PR should fix this, as it gives:

/home/alex/.local/share/flatpak/exports/share/applications/ OPEN,ISDIR 
/home/alex/.local/share/flatpak/exports/share/applications/ CREATE .export-symlink-6AHOii
/home/alex/.local/share/flatpak/exports/share/applications/ MOVED_FROM .export-symlink-6AHOii
/home/alex/.local/share/flatpak/exports/share/applications/ MOVED_TO org.gnome.gedit.desktop
/home/alex/.local/share/flatpak/exports/share/applications/ CLOSE_NOWRITE,CLOSE,ISDIR 

When installing gedit.