Comment 0 for bug 1730627

trusty's dpkg (1.17.5ubuntu5.7) cannot handle .deb files that contain control.tar files that are compressed using the xz compressor.

Here's an example of such a case when trying to show the contents of a .deb file from bionic's repositories:

dpkg-deb: error: archive './var/cache/apt/archives/ubuntu-minimal_1.406_amd64.deb' has premature member 'control.tar.xz' before 'control.tar.gz', giving up

This issue makes it currently impossible to create a bionic environment using debootstrap (currently from trusty-proposed).

I have observed the issue on trusty, precisely on

$ lsb_release -rd
Description: Ubuntu 14.04.5 LTS
Release: 14.04

using

$ apt-cache policy dpkg
dpkg:
  Installed: 1.17.5ubuntu5.7
  Candidate: 1.17.5ubuntu5.7
  Version table:
 *** 1.17.5ubuntu5.7 0
        500 mirror://mirrors.ubuntu.com/mirrors.txt/ trusty-updates/main amd64 Packages
        100 /var/lib/dpkg/status
     1.17.5ubuntu5.6 0
        500 http://security.ubuntu.com/ubuntu/ trusty-security/main amd64 Packages
     1.17.5ubuntu5 0
        500 mirror://mirrors.ubuntu.com/mirrors.txt/ trusty/main amd64 Packages