Comment 0 for bug 1894116

Deselecting all archs in the "Ubuntu extra architectures"/ubuntu-ports package repo blocks new deployments from happening with the following error:

"Error:Failed to retrieve curtin config: 'NoneType' object has no attribute 'url'"

When deselecting all archs and saving, the default archs are pulled in again (["amd64", "i386"]), which are filtered out by PackageRepository.get_ports_archive() because it looks for PORTS_ARCHES (["armhf", "arm64", "ppc64el", "s390x"]), triggering the error above.

The message doesn't give any information about the origin of the error. Given that this is a default repo, changing the archs pulled in when left empty or raising a warning when saving the changes seem to be good options for this bug.