Bug#793444: apt: jessie-backports non-free i386 packages causes "Falling back to normal index file acquire" error

[Chris Kuehl <ckuehl@ocf.berkeley.edu>]

Package: apt
Version: 1.0.9.8
Severity: normal

Howdy maintainers,

I've found what I believe to be a strange bug, either with apt or with
the current Debian apt repository.

We are seeing strange lines in our stderr when we run `apt-get update`:

    Falling back to normal index file acquire

This has been happening since July 15 and never before.

I found a way to reproduce the problem on our machines:

    $ rm /var/lib/apt/lists/mirrors.ocf.berkeley.edu_debian_dists_jessie-backports_non-free_binary-i386_Packages
    $ apt-get update > /dev/null  # no complaints
    $ apt-get update > /dev/null  # complains again!

I confirmed that our copy of the Packages file matches
http://ftp.us.debian.org/debian/dists/jessie-backports/non-free/binary-i386/Packages.gz
(currently SHA1 of 59fa80b71ee5c40948bb7f2a97e209b9eb97b443 un-gzipped)

This can be replicated in a clean jessie VM like so:

  1. dpkg --add-architecture i386
  2. echo 'deb http://ftp.us.debian.org/debian/ jessie-backports non-free' >> /etc/apt/sources.list
  3. apt-get update > /dev/null  # this one works
  4. apt-get update > /dev/null  # now we get a complaint to stderr

(Your apt config must not store Packages files gzipped. If you're
testing with the "official" Debian Docker images, you'll want to run
`rm /etc/apt/apt.conf.d/docker*` first.)

I can't find any immediate problems with the Packages file, so I'm not
sure where this bug is happening. Hopefully you can direct this to the
right place if it's not a bug in apt.

Many thanks!
Chris


-- System Information:
Debian Release: 8.1
  APT prefers stable-updates
  APT policy: (500, 'stable-updates'), (500, 'stable')
Architecture: amd64 (x86_64)

Kernel: Linux 3.16.0-4-amd64 (SMP w/8 CPU cores)
Locale: LANG=en_US.UTF-8, LC_CTYPE=en_US.UTF-8 (charmap=UTF-8)
Shell: /bin/sh linked to /bin/dash
Init: systemd (via /run/systemd/system)

Versions of packages apt depends on:
ii  debian-archive-keyring  2014.3
ii  gnupg                   1.4.18-7
ii  libapt-pkg4.12          1.0.9.8
ii  libc6                   2.19-18
ii  libgcc1                 1:4.9.2-10
ii  libstdc++6              4.9.2-10

apt recommends no packages.

Versions of packages apt suggests:
pn  apt-doc     <none>
ii  aptitude    0.6.11-1+b1
ii  dpkg-dev    1.17.25
ii  python-apt  0.9.3.11

-- no debconf information