.. This document is © Martin F. Krafft <mail@martin-krafft.net>
   It is available under the terms of the Creative Commons
   Attribution-NonCommercial-ShareAlike Licence 2.5

==========================================================================
Modern version control systems for cross-distro packaging
==========================================================================

.. |event| replace:: DebConf 8, Mar Del Plata, Argentina
.. |talkdate| replace:: 11 August 2008
.. |author| replace:: martin f. krafft
.. |authoremail| replace:: madduck@debian.org
.. |footer| replace:: |event| |bull| |talkdate|

.. container:: author

  |author| <|authoremail|>

  * `Debian`_ developer
  * Author of the book `The Debian System — Concepts and Techniques`_
  * `Ph.D. student`_, `Lero`_, `CSIS`_, `University of Limerick`_, Ireland

.. _Debian: http://debian.org/
.. _Ph.D. student: http://martin-krafft.net/phd/
.. _Lero: http://lero.ie/
.. _CSIS: http://www.csis.ul.ie/
.. _University of Limerick: http://ul.ie/
.. _The Debian System — Concepts and Techniques: http://debiansystem.info/

.. container:: event

  |event|
  |talkdate|

Introduction
============
Package maintenance is:

.. class:: incremental

  #. debianising the upstream source tree
  #. creating a package
  #. developing new features

     - distro-specific
     - package-format specific
     - intended for upstream

  #. tracking upstream, or importing new release tarballs

     - keeping track of upstream features
     - adjusting specific features

  ..

    This is pretty distro-independent!

What is vcs-pkg.org?
====================
.. class:: incremental

  - cross-distro
  - VCS-independent
  - an endeavour to determine a packaging workflow which accounts for all
    involved:

    - distros
    - QA, release, security teams
    - contributors

  ..

    The goal is enable distros to work together on the version control level

Overview of this talk
=====================

.. class:: current

  - New Debian source package formates

- A Debian packaging workflow using Git
- Where to go from here?

Debian source packages, version 3
=================================
``dpkg-source`` knows a few new (experimental) formats:

- git/bzr
- quilt

VCS source packages
===================
  Source packages consist of the (compressed, pruned) repository, which is
  checked out on unpack.

Arguments against:

.. class:: incremental

  - new tools required on build daemons and for ``build-essential``
  - VCS knowledge required to properly work on the package
  - dependencies on young, third-party tools

quilt source packages
=====================
The "wig&pen" format gets rid of ``diff.gz`` files and uses:

- ``dsc`` file, as before
- ``orig.tar.gz``, as before
- ``debian.tar.gz``, which unpacks to ``./debian``
- ``orig-$FEATURE.tar.gz``, which unpacks to ``./$FEATURE``

The use of ``./debian/patches`` is encouraged.

Thus, the task becomes how to extract ``./debian/patches`` from version
control.

Overview of this talk
=====================

- New Debian source package formates

.. class:: current

  - A Debian packaging workflow using Git

- Where to go from here?

Debian packaging with Git
=========================
  This workflow does not rely on Git-specific features and can be used with
  other VCSs

Used branches:

.. class:: incremental

  - ``upstream``, which tracks upstream
  - ``upstream/dist``, which contains ``autoconf``-dist changes
  - ``pristine-tar``, used to recreate tarballs
  - ``features/*``, features targetted for upstream
  - ``debian/*``, Debian-specific changes
  - ``debian``, the main Debianisation branch
  - ``build``, the integration branch used to build

Features of this workflow
=========================

.. class:: incremental

  - features can be developed and maintained independently
  - the repository contains everything needed to recreate pristine source
    packages
  - source packages contain patches for each feature (quilt series)

TopGit: managing patch queues with Git
======================================
.. class:: incremental

  - use an entire branch to track a patch
  - manage dependencies between patches
  - allow full use of Git features, including distributed development
  - similar to Bazaar looms and Mercurial patch queues

The big picture
===============
.. container:: center

  .. image:: workflow.png

Live demonstration?
===================

  Do you want to see this in action?

Overview of this talk
=====================

- New Debian source package formates
- A Debian packaging workflow using Git

.. class:: current

  - Where to go from here?

Working with other distros
==========================
- Why not use the same repository as e.g. Fedora?
- Additional feature branch families:

  - ``distro/*``: (optional) non-upstream changes applicable to *all* distros
  - ``rpm/*``/``deb/*``: package-format-specific changes
  - ``ubuntu/*``/``fedora/*``:  the ``debian/*`` counterparts

How can we make this happen?
============================
.. class:: incremental

  #. talk to other distros, map out requirements
  #. design a workflow, in collaboration
  #. try out the workflow with a few packages
  #. refine
  #. provide a wrapper which implements this workflow in a VCS-agnostic way
  #. Take over the world

My only friend, the end…
========================

  Thank you for your attention!

  * Mailing list: http://lists.madduck.net/listinfo/vcs-pkg
  * "Homepage": http://wiki.debian.org/VcsPackaging

  .. container:: author

    |author| <|authoremail|>

    * http://people.debian.org/~madduck/
    * http://martin-krafft.net/phd/

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