Re: APT 1.4.8 unable to resolve dependencies (possible regression wrt 1.4.6)

[Lukasz Walewski <ljw@icm.edu.pl>]

On 2018-02-07 13:48, Julian Andres Klode wrote:
> On Wed, Feb 07, 2018 at 01:13:50PM +0100, Lukasz Walewski wrote:
> > Hi,
> >
> > I build Debian-based filesystem images for embedded devices. By 
> > "image" I
> > mean a regular Debian 9.x (stretch) filesystem created with 
> > debootstrap with
> > some 3rd party packages installed on top of it. The filesystem is 
> > converted
> > into a *.iso image and burned into the NAND of an embedded device.
> >
> > The 3rd party software shipped with an image features some proprietary 
> > Java
> > application, that is (currently) compatible with JRE version 7 only, 
> > thus I
> > need openjdk-7-jre package installed in my images. Since openjdk-7-jre 
> > is
> > not available in Debian 9, I use Debian 8.x (jessie) mirror as a 
> > second
> > sources.list entry. So what I do is basically:
> >
> > 1. debootstrap from an official Debian stable mirror
> > 2. add official Debian oldstable mirror to /etc/apt/sources.list
> > 3. apt-get update
> > 4. apt-get install openjdk-7-jre
> >
> > The above procedure used to work with apt 1.4.6, i.e. the packages 
> > that
> > openjdk-7-jre depends upon (214 additional packages) were pulled in 
> > and
> > installed, which is what I expected:
> >
> > root@stretch-i386:~# apt -v
> > apt 1.4.6 (i386)
> >
> > root@stretch-i386:~# apt-get install openjdk-7-jre
> > Reading package lists... Done
> > Building dependency tree... Done
> > The following additional packages will be installed:
> > [...]
> > The following NEW packages will be installed:
> > [...]
> > The following packages will be upgraded:
> > [...]
> > 1 upgraded, 214 newly installed, 0 to remove and 0 not upgraded.
> > Need to get 146 MB of archives.
> > After this operation, 529 MB of additional disk space will be used.
> > Do you want to continue? [Y/n]
> >
> >
> > With apt 1.4.8 this does not work anymore - apt cannot resolve the
> > dependencies and fails:
> >
> > root@stretch-i386:~# apt -v
> > apt 1.4.8 (i386)
> >
> > root@stretch-i386:~# apt-get install openjdk-7-jre
> > Reading package lists... Done
> > Building dependency tree... Done
> > Some packages could not be installed. This may mean that you have
> > requested an impossible situation or if you are using the unstable
> > distribution that some required packages have not yet been created
> > or been moved out of Incoming.
> > The following information may help to resolve the situation:
> >
> > The following packages have unmet dependencies:
> >  openjdk-7-jre : Depends: openjdk-7-jre-headless (= 
> > 7u111-2.6.7-1~deb8u1)
> > but it is not going to be installed
> > E: Unable to correct problems, you have held broken packages.
> >
> >
> > What has changed from apt 1.4.6 to 1.4.8 that rendered my use case
> > unsupported? Is this behavior desired? What can I do to continue with 
> > my
> > workflow which is now broken?
>
> There were no changes that could cause that.

Yes, you are right, it's not apt version, it's apt cache. I am able to 
reproduce the failing scenario with apt 1.4.6 by taking an image from 
July 2017 (that still contains apt 1.4.6) and simply running "apt-get 
update" there.

Apparently the content of Debian stable changed since July 2017 in a 
way, that makes it impossible to resolve these dependencies 
automatically. I figured out, however, that I can help apt by specifying 
them explicitly:

root@stretch-i386:~# apt-get install openjdk-7-jre 
openjdk-7-jre-headless tzdata-java tzdata=2017c-0+deb8u1

Then it works...

Could you advise, what would be the proper way of handling such 
scenarios in general? - I can imagine, in some months the dependencies 
among at-that-time-current versions of Debian packages will change again 
and I will end up in a similar problem as described above. How to avoid 
such dependency hell in the future?

Best regards,
Lukasz