From dist.ini to .deb in one go
===============================
:author:    Axel Beckert <abe@debian.org>
:backend:   slidy
:data-uri:  https://noone.org/talks/pkg-perl/
:max-width: 94%
:icons:


Maintaining Debian Packages of Your Own Dist::Zilla based Perl Modules
----------------------------------------------------------------------

Typical VCS-Workflow for Building .deb Packages from Your Own Perl Module
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

1. Build CPAN tar-ball from `master` branch with `dzil build`
2. Switch to the `upstream` branch
3. Import the contents of the tar-ball destined for CPAN into VCS
4. Merge the `upstream` branch into the `debian` branch
5. Update packaging (`debian/changelog`, etc.)
6. Build `.deb` package

What we want
~~~~~~~~~~~~

* Building the `.deb` directly from a VCS checkout
* Skip manual tar-ball generation and reimport
* Don't commit generated files to VCS

dh-dist-zilla
-------------

Obstacles
~~~~~~~~~

* `dh-make-perl` (for bootstrapping the Debian packaging) needs CPAN
  meta data.

** Solution: Run `dh-make-perl` once manually inside the
  `dzil`-generated build directory, copy `debian/` subdirectory back
  into the project root directory.

* debhelper (`dh`) only knows about `Build.PL` and `Makefile.PL`, not
  about `dist.ini`

Debhelper Sequence Modification
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

* Generate build directory before debhelper looks for the existing of
  `Build.PL` or `Makefile.PL`.

** Call `dzil build` before `dh_auto_configure`
** Ignore generated tar ball

* Build package inside the generated build directory

** Pass build directory option `-D` to `dh_auto_configure`,
   `dh_auto_build`, `dh_auto_test` and `dh_auto_install`.

* Easy cleanup: Just delete the build directory.

** Call `dzil clean` before `dh_auto_clean`.

How do I use dh-dist-zilla in my Debian package?
------------------------------------------------

It's as simple as this `debian/rules` file:

  #!/usr/bin/make -f
  %:
  	dh $@ --with dist-zilla

Additionally, a build-dependency on `dh-dist-zilla` is needed.

Untypical Workflow
~~~~~~~~~~~~~~~~~~

Expected / Traditional:

* VCS → `dzil build` → CPAN tar-ball ∈ Debian Source Package → Debian Binary Package

dh-dist-zilla:

* VCS → `dzil build` → CPAN tar-ball
* VCS = Debian Source Package → Debian Binary Package


Links
-----

Slides
~~~~~~

- https://noone.org/talks/pkg-perl/
- Contact:
** Axel Beckert <abe@debian.org>
** Elmar Heeb <elmar@heebs.ch>

Tools
~~~~~

- dh-dist-zilla: https://github.com/elmar/dh-dist-zilla
** Available in Debian Testing
- debhelper: http://joeyh.name/code/debhelper/
- Dist::Zilla: http://dzil.org/
- dh-make-perl: https://metacpan.org/release/DhMakePerl

Examples
~~~~~~~~

- Run::Parts: https://github.com/xtaran/run-parts
- Bio-Roary: https://anonscm.debian.org/cgit/debian-med/roary.git/tree/debian/rules