Bug#730490: apt: invoking dpkg no longer respects APT::Keep-Fds

[Michael Vogt <mvo@debian.org>]

On Mon, Nov 25, 2013 at 04:51:12PM +0000, Colin Watson wrote:
> Package: apt
> Version: 0.9.13
> Severity: grave
> Justification: breaks d-i
> Tags: patch
> User: ubuntu-devel@lists.ubuntu.com
> Usertags: origin-ubuntu ubuntu-patch trusty

Thanks for your bugreport and your patch.
 
> This bug originated as:
> 
>   https://bugs.launchpad.net/bugs/1254696
> 
> The ExecFork refactoring in 0.9.13~exp1 broke d-i, because APT::Keep-Fds
> is no longer respected when invoking dpkg.  Here's a patch, although
> perhaps you want this laid out in some way that duplicates less code;
> however I couldn't readily see how to do that without just undoing the
> refactoring.

Sorry for this regression. I had hoped to get rid of the APT::Keep-Fds
and replace it with a proper APT::Progress::PackageManager object. But
obviously its not ready yet. I merged your patch but moved the Keep-Fd
reading into its own function.

> I spent a couple of hours trying to write an integration test that
> exercises the whole debconf-apt-progress path.  I failed because that
> requires actually executing the postinst in a test package, which
> requires chrooting because we use dpkg --root, and I couldn't get
> fakechroot to do the right thing.  Suggestions gratefully appreciated if
> you think this is important.
> 
>   * Fix two subprocess calls to continue to honour APT::Keep-Fds
>     (LP: #1254696).

Having a test for this would be good - it will keep me from breaking
it again :) If you could post the current state of your test that
would be helpful.

Thanks,
 Michael