Bug#972645: gnome-builder does not start without flatpak package installed

[nodiscc]

Package: gnome-builder
Version: 3.30.3-2
Severity: grave
Debian 10 Buster

Dear maintainer,

gnome-builder does not start at all when the flatpak package is not
installed, and returns code 255. gneom-builder *recommends*
flatpak-builder which in turns depends on flatpak, but if you have
like me disabled installation of recommended packages by defautl the
the program won't start at all.

flatpak should be a hard dependency for the gnome-builder package.

Thanks

$ gnome-builder
ptrace: Operation not permitted.
No threads.
No shared libraries loaded at this time.
# gnome-builder does not start

$ echo $?
255

$ sudo apt install flatpak
...

$ gnome-builder
# gnome-builder starts properly