[Pkg-zsh-devel] Bug#770226: Bug#770226: zsh-common: installation fails for amd arch

[Axel Beckert]

Hi Scott,

thanks for the bug report.

Scott Walsh wrote:
> aptitude install zsh, which lead to packages being in the 'half'
> installed state. Attempting to purge was unsucessful. Had to resort to
> dpkg --remove --force-remove-reinstreq zsh zsh-common to resolve the
> issue.

That's strange, because I would expect that piuparts would find such
issues, but definitely didn't, neither at
https://piuparts.debian.org/sid/source/z/zsh.html nor at
http://jenkins.grml.org/view/Debian/job/zsh-piuparts/

>   Preparing to unpack .../zsh-common_5.0.7-4_all.deb ...
>   dpkg-maintscript-helper: error: original symlink target is not an
>   absolute path
>   dpkg: error processing archive
>   /var/cache/apt/archives/zsh-common_5.0.7-4_all.deb (--unpack):

This is clearly something which was introduced by one of the fixes in
5.0.7-4 as we didn't use dpkg-maintscript-helper before.

I tried to reproduce this issue in a freshly bootstrapped jessie
chroot, but couldn't (which doesn't surprise me much as piuparts
couldn't either).

So we need to see what so special in your setup.

One thing which is a good candidate for such a failure is a too old
dpkg version. Both, zsh and zsh-common have a "Pre-Depends: dpkg (>=
1.17.5)" because of this, but maybe that Pre-Depends is not strict
enough (despite it has been set by debhelper for using
dpkg-maintscript-helper with symlink_to_dir. But reading dpkg's
changelog.Debian.gz, I find the following entry for 1.17.14:

  * Add support for relative symlinks to dpkg-maintscript-helper
    symlink_to_dir command. [...]

So I suspect this happened with a dpkg version < 1.17.14 and we likely
need to bump that Pre-Depends to >= 1.17.14.

Cc'ing debhelper-devel to make them aware of this potential issue.

debhelper maintainers: Shall I clone or reassign this bug report to
debhelper for bumping ${misc:Pre-Depends} in such cases?

To be sure that my assumption is correct: Scott, can you tell me the
dpkg version which was running at that time. If the dpkg has changed
since then or was upgraded in the same run, please look in
/var/log/aptitude or /var/log/dpkg.log which was installed when that
error happened. (Verifying that dpkg was either uptodate in Jessie or
below version 1.17.14 at the time when this happened should suffice.)

		Regards, Axel
-- 
 ,''`.  |  Axel Beckert <abe at debian.org>, http://people.debian.org/~abe/
: :' :  |  Debian Developer, ftp.ch.debian.org Admin
`. `'   |  1024D: F067 EA27 26B9 C3FC 1486  202E C09E 1D89 9593 0EDE
  `-    |  4096R: 2517 B724 C5F6 CA99 5329  6E61 2FF9 CD59 6126 16B5