I recently completed and released some work on Debian’s tooling for packaging Emacs Lisp addons to GNU Emacs. Emacs grew a package manager called package.el a few years ago, and last year David Bremner wrote the dh_elpa tool to simplify packaging addons for Debian by leveraging package.el features. Packaging a series of addons for Debian left me with a wishlist of features for dh_elpa and I was recently able to implement them.

Debian tooling generally uses Perl, a language I didn’t know before starting on this project. I was fortunate enough to receive a free review copy of Perl 5 by Example when I attended a meeting of the Bay Area Linux Users Group while I was visiting San Francisco a few months ago. I accepted the book with the intent of doing this work.

dh_make_elpa

dh_make_elpa (at present available from Debian experimental) is a Perl script to convert a git repository cloned from the upstream of an Emacs Lisp addon to a rudimentary Debian package. It performs a lot of guesswork, and its simple heuristics are something I hope to improve on. Since I am new to object-oriented program design in Perl and I wanted to leverage object-oriented Debian tooling library code, I took the structure of my project from dh_make_perl. In this manner I found it easy and pleasant to write a maintainable script.

dh_elpa_test

A lot of Emacs Lisp addon packages use a program called Cask to manage the Emacs Lisp dependencies needed to run their test suites. That meant that dh_auto_test often fails to run Emacs Lisp addon package test suites. Since the Debian packaging toolchain already has advanced dependency management, it’s undesirable to involve Cask in the package build pipeline if it can be avoided. I had been copying and pasting the code needed to make the tests run in our environment to the debian/rules files of each package whose test suite I wanted to run.

dh_elpa_test tries to detect Emacs Lisp addon package test suites and run them with the workarounds needed in our environment. This avoids boilerplate in debian/rules. dh_elpa_test also disables dh_auto_test to avoid a inadvertent Cask invocation.

Future & acknowledgements

My hope for this work was to make it easier and faster to package Emacs Lisp addon packages for Debian, for my own sake and for anyone new who is interested in joining the pkg-emacsen team. In the future, I want to have dh_elpa_test generate an autopkgtest definition so that a Testsuite: pkg-emacsen line in debian/control is enough to have an Emacs Lisp addon package test suite run on Debian CI.

I’m very grateful to David Bremner for reviewing and supporting this work, and also for supporting my Emacs Lisp addon packaging work more generally.

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