Comment 13 for bug 1730627

Built a test package with the upstream patch here:
https://launchpad.net/~ddstreet/+archive/ubuntu/lp1730627

Then tested autopkgtest on bionic system, with the patched dpkg. Fails as expected with the current trusty dpkg:

$ autopkgtest -U dpkg_1.17.5ubuntu5.8.dsc -- lxd ubuntu-daily:trusty
...
autopkgtest [15:20:15]: ERROR: "dpkg --unpack /tmp/autopkgtest.wuLHN3/autopkgtest-satdep.deb" failed with stderr "dpkg-deb: error: archive '/tmp/autopkgtest.wuLHN3/autopkgtest-satdep.deb' has premature member 'control.tar.xz' before 'control.tar.gz', giving up

Build/autopkgtest successful with the patched trusty dpkg from PPA:

$ autopkgtest --setup-commands='sudo apt-add-repository ppa:ddstreet/lp1730627' -U dpkg_1.17.5ubuntu5.8.dsc -- lxd ubuntu-daily:trusty
...
dpkg-deb: building package `dpkg-dev' in `../dpkg-dev_1.17.5ubuntu5.8_all.deb'.
 dpkg-genchanges -b >../dpkg_1.17.5ubuntu5.8_amd64.changes
dpkg-genchanges: binary-only upload - not including any source code
 dpkg-source --after-build src
dpkg-source: info: using options from src/debian/source/options: --compression=xz
dpkg-buildpackage: binary only upload (no source included)
dpkg-source: info: using options from src/debian/source/options: --compression=xz
* SKIP no tests in this package
autopkgtest [15:29:22]: @@@@@@@@@@@@@@@@@@@@ summary
* SKIP no tests in this package