Merges & syncs

This article explains how and why Ubuntu imports changes from Debian.

How does Ubuntu import changes from Debian

Because Ubuntu is derived from Debian and uses the same package management system (APT), most changes made to Debian can also be applied to Ubuntu.

Syncs and merges are the two processes through which Ubuntu developers integrate updates and improvements from Debian into the Package archive.

Sync

Sync (synchronization with Debian) is the automatic copying of new packages from Debian unstable (code name “Sid”) to the Ubuntu Archive. This includes packages that have not been in the distribution before and packages with higher version identifiers than the corresponding Ubuntu packages. Corresponding Ubuntu packages that carry Ubuntu delta are excluded from the sync.

The sync process runs from the opening of the Ubuntu Archive for a new release until the Debian Import Freeze.

On request (via a Launchpad ticket), archive admins can sync a package from Debian even if the Ubuntu package carries an Ubuntu delta. In this case, the Ubuntu delta is dropped. A good example is when Ubuntu-specific changes have been merged into the Debian package or the upstream project and are no longer needed.

Getting packages from Debian to Ubuntu outside of the sync process

After the Debian Import Freeze and before the Final Release, you must request the respective freeze exception.

After the Final Release, you must follow the Stable Release Updates process. For additional details about the freezes, see the Release cycle article.

Merges

When importing a newer Debian package into Ubuntu, a merge must be performed if the corresponding Ubuntu package carries an Ubuntu delta that needs to be partially or fully applied to the Debian package.

The Ubuntu Merge-o-Matic (MoM) service automatically performs merges and publishes the reports on merges.ubuntu.com. See the lists of outstanding merges for:

• main

• universe

• restricted

• multiverse

To complete a merge, interaction and supervision by Ubuntu maintainers are required. See TODO for details on performing a merge.

See the section Components in the article that explains the Ubuntu package archive for an explanation of main, universe, restricted, and multiverse.

Why does Ubuntu import changes from Debian

Ubuntu incorporates changes from Debian through merging and syncing to leverage the extensive work and improvements made by the Debian community. Debian provides a stable foundation and a vast repository of packages. By integrating changes from Debian, Ubuntu can focus on refining the user experience. At the same time, the consistency between Ubuntu and Debian allows for sharing resources (e.g., testing and bug fixing) and contributing back to the open-source ecosystem, ultimately benefiting both distributions and their users.