[Bug 346386] Re: [MASTER] Update fails with invalid package files with "Encountered a section with no Package: header"

[Brian Murray]

The reason that we reopened this bug report is that we are seeing
duplicates of it reported from precise users, which should have a fixed
version of apt installed.  Using the tool lp-bug-dupe-properties from
lptools we can see the following:

./lp-bug-dupe-properties --bug 346386 --rtags
…
precise: 946692 948744 967411 989262 989270 989293 989602 996030 1001769 1001932 1006103

Of those bug 1006103 has the most details.

I am also able to recreate this bug by performing the following steps:

1) Edit some packages file in  /var/lib/apt/lists/ to be missing a Package: line or just remove the whole file
2) Run 'sudo apt-get update'
3) Observe the message 'Encountered a section with no Package: header' … 'Problem with MergeList'

I took the above steps instead of trying to create a proxy server that
would block access to the archive.  Even if this test is bad it is still
worrisome that we are actively receiving duplicates of this bug.

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https://bugs.launchpad.net/bugs/346386

Title:
  [MASTER] Update fails with invalid package files with "Encountered a
  section with no Package: header"

Status in “apt” package in Ubuntu:
  Triaged
Status in “apt” source package in Natty:
  Fix Released
Status in “apt” package in Debian:
  Fix Released

Bug description:
  Binary package hint: adept-updater

  Pertinent data printed when attempting to run Updater as follows:

  An unresolvable problem occurred while initializing the package
  information.

  Please report this bug against the 'update-manager' package and
  include the following error message:

  'E:Encountered a section with no Package: header, E:Problem with
  MergeList /var/lib/apt/lists/us.archive.ubuntu
  .com_ubuntu_dists_intrepid_universe_binary-amd64_Packages, E:The
  package lists or status file could not be parsed or opened.'

  WORKAROUND:
  Remove problematic files from /var/lib/apt/lists/ and rerun apt-get update.

  In the event that one is connected to a network with a proxy server
  that returns html pages (like a web page requesting you to login) and
  not package list files.   Those html files will get downloaded to
  /var/lib/apt/lists/ and prevent someone from using a package manager
  until the problem html pages are removed.

  TEST CASE:
  1) Ensure /etc/apt/sources.list points to archive.ubuntu.com
  2) Setup proxy server to block access to archive.ubuntu.com and return something like http://people.canonical.com/~brian/tmp/not-packages.html
  3) Execute 'sudo apt-get update' in a terminal
  4) Observe the following:
  'E: Encountered a section with no Package: header
   E: Problem with MergeList /var/lib/apt/lists/archive.ubuntu.com_ubuntu_dists_natty_main_binary-amd64_Packages
   E: The package lists or status file could not be parsed or opened.'
  5) Try 'apt-cache policy apt' and be sad that it doesn't work
  6) run 'sudo rm /var/lib/apt/lists/*Packages' to clear the error.

  With the proposed package installed repeat steps 1 to 3.
  4) Observe the following:
  ''Get:1 http://archive.ubuntu.com oneiric InRelease [189 B]
  Ign http://archive.ubuntu.com oneiric InRelease
  E: GPG error: http://archive.ubuntu.com oneiric InRelease: The following signatures were invalid: NODATA 1 NODATA 2'
  5) Try 'apt-cache policy apt' and be happy that it works

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