Could not calculate the upgrade

[Nicolas]

An unresolvable problem occurred while calculating the upgrade.

 This can be caused by:
 * Upgrading to a pre-release version of Ubuntu
 * Running the current pre-release version of Ubuntu
 * Unofficial software packages not provided by Ubuntu

If none of this applies, then please report this bug using the command 'ubuntu-bug ubuntu-release-upgrader-core' in a terminal.

ProblemType: Bug
DistroRelease: Ubuntu 12.04
Package: update-manager 1:0.156.14.17
ProcVersionSignature: Ubuntu 3.13.0-34.60~precise1-generic 3.13.11.4
Uname: Linux 3.13.0-34-generic x86_64
ApportVersion: 2.0.1-0ubuntu17.6
Architecture: amd64
Date: Sun Aug 17 10:39:21 2014
GsettingsChanges:
 com.ubuntu.update-manager first-run false
 com.ubuntu.update-manager launch-time 1408282442
 com.ubuntu.update-manager window-height 604
 com.ubuntu.update-manager window-width 600
InstallationMedia: Ubuntu 12.04.2 LTS "Precise Pangolin" - Release amd64 (20130213)
MarkForUpload: True
PackageArchitecture: all
ProcEnviron:
 TERM=xterm
 PATH=(custom, no user)
 LANG=en_US.UTF-8
 SHELL=/bin/bash
SourcePackage: update-manager
Symptom: ubuntu-release-upgrader-core
UpgradeStatus: Upgraded to precise on 2014-08-17 (0 days ago)
VarLogDistupgradeTermlog:

[Brian Murray (brian-murray)]

From VarLogDistupgradeMainlog:

Investigating (0) python3 [ amd64 ] < 3.2.3-0ubuntu1.2 -> 3.4.0-0ubuntu2 > ( python )
Broken python3:amd64 Depends on python3.4 [ amd64 ] < none -> 3.4.0-2ubuntu1 > ( python ) (>= 3.4.0-0~)
  Considering python3.4:amd64 4 as a solution to python3:amd64 381
  MarkKeep python3 [ amd64 ] < 3.2.3-0ubuntu1.2 -> 3.4.0-0ubuntu2 > ( python ) FU=0
  Removing python3:amd64 rather than change python3.4:amd64
  MarkDelete python3 [ amd64 ] < 3.2.3-0ubuntu1.2 -> 3.4.0-0ubuntu2 > ( python ) FU=1
Investigating (0) python3-gi [ amd64 ] < 3.2.2-1~precise -> 3.12.0-1ubuntu1 > ( python )
Broken python3-gi:amd64 Depends on python3 [ amd64 ] < 3.2.3-0ubuntu1.2 -> 3.4.0-0ubuntu2 > ( python ) (< 3.5)
  Considering python3:amd64 381 as a solution to python3-gi:amd64 101
  MarkKeep python3-gi [ amd64 ] < 3.2.2-1~precise -> 3.12.0-1ubuntu1 > ( python ) FU=0
  Removing python3-gi:amd64 rather than change python3:amd64
  MarkDelete python3-gi [ amd64 ] < 3.2.2-1~precise -> 3.12.0-1ubuntu1 > ( python ) FU=1
Investigating (0) python3-minimal [ amd64 ] < 3.2.3-0ubuntu1.2 -> 3.4.0-0ubuntu2 > ( python )
Broken python3-minimal:amd64 Depends on python3.4-minimal [ amd64 ] < none -> 3.4.0-2ubuntu1 > ( python ) (>= 3.4.0-0~)
  Considering python3.4-minimal:amd64 1 as a solution to python3-minimal:amd64 95
  MarkKeep python3-minimal [ amd64 ] < 3.2.3-0ubuntu1.2 -> 3.4.0-0ubuntu2 > ( python ) FU=0
  Holding Back python3-minimal:amd64 rather than change python3.4-minimal:amd64
Investigating (0) dh-python [ amd64 ] < none -> 1.20140128-1ubuntu8 > ( python )
Broken dh-python:amd64 Depends on python3:any [ amd64 ] < none > ( none ) (>= 3.3.2-2~)
  Considering python3:i386 0 as a solution to dh-python:amd64 94
  MarkKeep dh-python [ amd64 ] < none -> 1.20140128-1ubuntu8 > ( python ) FU=0
  Holding Back dh-python:amd64 rather than change python3:any:amd64

[Launchpad Janitor (janitor)]

Status changed to 'Confirmed' because the bug affects multiple users.