emerge complains about blocked packages: what do I do?

Question

We have an old development server running Gentoo at work. I would like to update this system, but I keep running into problems with the packaging system. To me, it seems like there are dependencies on several versions of various packages, and I cannot see how to fix it.

The biggest problem is probably relating to Python and Portage. I need a newer portage, but there seems like there are cyclical dependencies going on.

I have tried various solutions, but not quite sure to go from here. Any clues that might get me further in fixing it?

Further information

The following is the (relevant bit of the) output from running emerge --update --newuse --deep @world

(lots of normal output ....)
[ebuild     U ] app-misc/mc-4.7.0.3 [4.6.1-r4] USE="edit%* -slang*" 
....
[blocks B     ] >=dev-lang/python-2.6.6 (">=dev-lang/python-2.6.6" is blocking sys-apps/portage-2.1.6.7)
[blocks B     ] <sys-apps/portage-2.1.7.16 ("<sys-apps/portage-2.1.7.16" is blocking app-shells/bash-4.1_p9)
[blocks B     ] <sys-apps/portage-2.1.9 ("<sys-apps/portage-2.1.9" is blocking dev-lang/python-2.7.1-r1)

 * Error: The above package list contains packages which cannot be
 * installed at the same time on the same system.

  (dev-lang/python-2.7.1-r1, ebuild scheduled for merge) pulled in by
    =dev-lang/python-2* required by (dev-vcs/mercurial-1.7, ebuild scheduled for merge)
    =dev-lang/python-2*[threads] required by (dev-vcs/mercurial-1.7, ebuild scheduled for merge)
    =dev-lang/python-2* required by (dev-libs/glib-2.28.6, ebuild scheduled for merge)
    (and 1 more)

  (app-shells/bash-4.1_p9, ebuild scheduled for merge) pulled in by
    >=app-shells/bash-3.2_p17 required by (sys-apps/portage-2.1.9.42, ebuild scheduled for merge)
    app-shells/bash required by (sys-block/di-4.18, ebuild scheduled for merge)
    app-shells/bash required by (app-admin/perl-cleaner-2.7, ebuild scheduled for merge)
    (and 2 more)

  (dev-lang/python-3.1.3-r1, ebuild scheduled for merge) pulled in by
    dev-lang/python required by (app-admin/python-updater-0.9, ebuild scheduled for merge)
    >=dev-lang/python-3 required by (sys-apps/portage-2.1.9.42, ebuild scheduled for merge)
    =dev-lang/python-3.1* required by (dev-java/java-config-2.1.11-r3, ebuild scheduled for merge)

This is the relevant bit of the output when running emerge --pretend --depclean

Calculating dependencies... done!
 * Dependencies could not be completely resolved due to
 * the following required packages not being installed:
 * 
 *   >=dev-lang/python-2.4 pulled in by:
 *     sys-apps/portage-2.1.6.7
 * 
 *   dev-lang/python pulled in by:
 *     dev-java/java-config-2.1.7
 * 
 *   dev-lang/python pulled in by:
 *     dev-libs/libxml2-2.6.31
 * 
 *   <dev-lang/python-2.6.6 pulled in by:
 *     sys-apps/portage-2.1.6.7
 * 
 *   >=dev-lang/python-2.2 pulled in by:
 *     dev-libs/beecrypt-4.1.2-r1
 * 
 *   virtual/python pulled in by:
 *     dev-python/pycrypto-2.0.1-r6
 * 
 *   >=dev-lang/python-2.3 pulled in by:
 *     dev-vcs/mercurial-1.0.2
 * 
 *   >=dev-java/java-config-2.1.9-r1 pulled in by:
 *     dev-libs/beecrypt-4.1.2-r1
 * 
 *   virtual/python pulled in by:
 *     dev-lang/swig-1.3.34
 * 
 *   dev-lang/python pulled in by:
 *     net-fs/samba-3.0.28a-r1
 * 
 *   >=dev-lang/python-2.2 pulled in by:
 *     app-arch/rpm-4.4.6-r6
 * 
 *   >=virtual/python-2.2.1 pulled in by:
 *     sys-libs/libcap-1.10-r11
 * 
 *   dev-lang/python pulled in by:
 *     sys-libs/cracklib-2.8.9-r1
 * 

Answer 1

I faced the same problem just a few days ago. I have no exact way how to do it, but here is the generic way:

First have a look at /var/lib/portage/world. Make a backup and strip down the packages to the ones neede by your system to boot up. Here's some content to get you going:

app-admin/syslog-ng
net-firewall/iptables
net-misc/dhcpcd
sys-apps/pciutils
sys-apps/slocate
sys-apps/usbutils
sys-boot/grub
sys-kernel/gentoo-sources
sys-power/acpid
sys-process/vixie-cron
virtual/inetd

Everything else will be updated later.

The most critical part is to get portage and python to recent versions so let's focus on that.

1. Emerge your portage dir:

   emerge --sync
   

   or:

   emerge-webrsync
   

2. Set a valid profile

   eselect profile list
   eselect profile set <x>
   

3. Upgrade python / portage step by step.

   Have a look at your current installed portage version. Upgrade portage to the next version higher than your current one (even if its masked by ~x86), then do the same for python. After a python upgrade make sure to run python-updater.

   Do this step by step until python/portage are up to date. (You may skip some of the minor version upgrades. You'll see for yourself which versions result in compile errors and which do.)

4. As soon as they work try to emerge some other packages as they might help you in your task.

   app-portage/ufed
   app-portage/autounmask
   app-portage/gentoolkit
   

5. Once python/portage are up to date you can restore your old world file and update your system.

   emerge -pvauDN world
   

   You might need to call:

   emerge ...
   emerge --depclean
   revdep-rebuild
   

   several times during the build process.

Answer 2

If problem in python then try running python-updater Note that you can select current version of python by command eselect