Ubuntu development

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TODO: This page could probably be broken up and used as overview/intros for many of our landing pages.

Overview of development

The development of Ubuntu is transparent to the public, and open to any contributor with the necessary skills and commitment to the project.

Ubuntu is based on Debian, sharing many packages, tools and techniques with that project. Like most operating systems, Ubuntu is complex, and it can help to get a broad overview of its architecture first.

Ubuntu is periodically released according to a set schedule.

If you have been directed to this page for advice on contributing to Ubuntu as a developer, you may also be interested in Contribute To Ubuntu.

Working with other developers

You are not alone! Ubuntu is the work of many developers, and we devote our efforts to enabling efficient collaboration with tools, infrastructure, governance and a cooperative spirit.

Starting points

Ubuntu developers explains the roles of developers in the Ubuntu project and how to join the teams.

If you are brand new to Ubuntu development and need to install the development tool set, or need step by step reminder on how to, check out the Ubuntu Beginner Developers’ Tools Installation Quick Start

If you’re looking for tasks which need doing, many of those are tracked in the bug tracking system. The The Bug Squad maintains several lists of them at Bugs/Tags.

If you already have experience working with Debian packages, most of your knowledge applies equally well to Ubuntu packaging. If you are a Debian developer, Ubuntu For Debian Developers summarizes the differences between the projects, and later sections in this document provide details of our infrastructure.

To submit patches for review or to help reviewing patches, refer to the Code Review process.

To find the developer responsible for the component you’re working on, see Developer Responsibilities.

Communication

Email discussion among Ubuntu developers takes place on the ubuntu-devel mailing list, which is moderated (excepting registered Ubuntu developers). The ubuntu-devel-discuss mailing list is available for open discussion about Ubuntu development (not for reporting bugs or user support). All Ubuntu developers should subscribe to the ubuntu-devel-announce mailing list, where important development events are announced. Various other mailing lists are available, some of which focus on specific areas of development.

The #ubuntu-devel channel on Matrix is home to many Ubuntu developers for real-time communication. Automated notifications of development activity are also useful for keeping up with what other developers are working on.

A comprehensive matrix of communication channels can be found on Developer Communication.

Bugs and the Bug Squad

Ubuntu bug reports are tracked in Launchpad. Helping with bugs contains information about how they are handled. The The Bug Squad documentation describes how to cooperate with other developers and volunteers working on bug triage; it is required reading for new developers, as developers will typically need to spend a significant amount of time working with the bug tracking system.

The Bug Squad (and the Ubuntu Bug Control team, which is comprised of more experienced triagers who can prioritize bugs) are here to help you as a developer. If you are responsible for a non-trivial number of bugs, it is a good idea to spend some time helping them to help you. A useful starting point is to add specific information about your packages to Debugging Procedures: this may include both special tricks for debugging them effectively and any particular policy you have on how you want your bugs to be handled (e.g. assignment, tags, etc.). When adding significant chunks of new information to Debugging Procedures, please send a note to ubuntu-bugsquad@lists.ubuntu.com about it.

Members of the Bug Squad can be found on the #ubuntu-devel channel on Matrix. There is also the ubuntu-bugsquad mailing list for general discussion regarding bugs and bug triaging.

Papercuts

Papercuts are trivial-to-fix but annoying bugs. Ideal for getting started helping with bugs.

Release-critical bugs

RC Bug Targeting documents the intended use of the various facilities of the bug tracking system to track release-critical bugs.

Showstopper bugs

Critical and milestoned to the relevant release. These bugs will hold up the release if not fixed.

Release-critical bugs

Critical and high importance bugs milestoned to the relevant release. Those bugs need to be fixed or worked around/documented before the release.

In particular, if you make a temporary change to a package for whatever reason which should be reverted before release, please file a release-critical bug about it so that this can be tracked by the release team.

The release process

Ubuntu does time-based releases. The Release Process section covers all the release management steps such as beginning a new release, planning it, merging with upstream, feature development, stabilization and freezes, milestone, finalization and stable releases.

Packaging

If you’re interested in packaging work, but don’t have much experience yet, you should read the MOTU getting started guide to get involved in the MOTU team.

Working with Debian-format packages

Ubuntu uses the Debian packaging format. The following resources explain how to create and modify Debian-format packages.

Working with Ubuntu packages

  • Set the target suite in debian/changelog to be the code name of the current development branch, e.g. dch -D zesty.

  • When working with a package which originated in Debian, use a version number derived from the Debian version number with ubuntu\<revision\> appended. e.g. Debian 1.0-2 becomes 1.0-2ubuntu1, followed by 1.0-2ubuntu2, etc.

  • When fixing a bug tracked in Launchpad, be sure to insert LP: #xxxxxx notation in your changelog entry, for example:

    mypackage (2.2-2) zesty; urgency=low

* hello(1) now prints "Hello, world!" instead of "Hello yourself." (LP: #500000)

 -- A. Developer <[email protected]> Mon, 17 Dec 2007 18:27:50 +0000

    Note: The regex in Launchpad looks for LP: #xxxxxx at a minimum. The preferred form is (LP: #xxxxxx).

  • When creating a new package that may later be added to Debian, use a revision of the form -0ubuntu1.

  • Remember to include the orig.tar.gz if this is a new upstream version of a non-native package but you have already patched it before upload. A missing original tarball may cause the upload to be rejected or silently dropped. Use dpkg-buildpackage -S -sa to generate such an upload. If the orig.tar.gz is already in the distribution then you don’t need to upload it again.

  • Always be aware of the release schedule and any applicable Freezes. The cooperation of all developers is needed to ensure a successful release!

  • If your changes may affect the work of other developers, it is a good idea to discuss the changes on a mailing list first.

  • For merging a Ubuntu package with a newer Debian version, see Merging.

Revision control (Bazaar)

Bazaar, an open source revision control system and Canonical sponsored project, is the preferred revision control system in Ubuntu. Many Ubuntu packages are maintained in Bazaar, which makes it easy for other developers to contribute changes to them, which can be easily merged by the maintainer.

Note that, as a practical matter, many packages are not yet maintained in Bazaar, but in other revision control systems or none on a case-by-case basis. Work is underway to rectify this. Where no revision control system is used, the history of uploads recorded in Launchpad may be useful.

Ubuntu Flavors and derivative distributions

The Ubuntu project produces several distributions each release cycle. These are sometimes called “Flavours”. Kubuntu, Edubuntu, and Xubuntu are all maintained directly in the Ubuntu Archive. There are also a large number of derivative distributions that are based on the Ubuntu Archive, but separately developed.

Upstream

“Upstream” is the term used to describe all the places where Ubuntu pulls its software from. The developers of this software write it and then it flows downstream in to Ubuntu and then in to its derivatives.

See Why upstream? for why upstream is so important, and some tips on working with upstream to improve the software, and hence Ubuntu.

There is one upstream that is critical to Ubuntu: Debian. This is where most of the packages in Ubuntu come from, and so working with them is important.

Building

You should always build and test packages locally before submitting them to Ubuntu. Failure to do so will waste the time of other members of the community, so please be considerate.

Tools

Ubuntu Developers’ Tools Installation Quick Start

You will find some tools explained in the Guides for contributors, also from Gutsy on, you will find ubuntu-dev-tools in the Archive, which contains tools for developing Ubuntu.

New packages

The process for either requesting a new package or getting your own new package included in Ubuntu is described at New packages.

The Package Archive

All current official Ubuntu packages are stored in the primary Package Archive, which is widely mirrored. It is administered by the Archive Administration team. The Packaging Archive section covers details such as interactions with the build daemons and the Archive. It also explains how different architectures and package components are handled and how the autobuilders work.

Installation media

The Installation media section discusses the different supported installation media types, how to obtain them and contains pointers to Installer development.

Language packs: internationalisation and localisation

We do not ship upstream translations from source packages directly in binary application packages in main and restricted, since this does not allow us any flexibility to edit them in a central place (Launchpad), update them independently from the applications, and update them post-release. That is why we separate packages and their translations in Ubuntu and maintain/package them independently.

The complete lifecycle of translations (import, maintenance, export, and language pack structure) is described in Translation Lifecycle.

The main article is at Internationalisation Guide for Developers

Other Resources

These resources should be incorporated into new or existing sections elsewhere in this document, but are temporarily recorded here so that we remember to come back to them later: