Implementation of Debian Import Freeze

During the Hardy and Intrepid cycles, there has been some confusion regarding Debian Import Freeze, and how this affects developers and constrains their activities. This page serves to collect viewpoints on various issues surrounding this freeze, to better inform the Technical Board if they choose to establish or publish policy governing this freeze.

Defintion

According to the Community Documentation, Debian Import Freeze is defined as follows:

Prior to this date, new versions of packages will be automatically imported from Debian unstable where they have not been customized for Ubuntu, that is when the version number of the package in the current Ubuntu development branch does not contain the substring "ubuntu" and there is a newer version in Debian. Entirely new packages (those not in Ubuntu at all) are also automatically imported prior to this date. The import is done by copying the source package verbatim from Debian and building fresh binary packages on the Ubuntu autobuilders.

By this date, all packages that have been modified by both Debian and Ubuntu since the last merge should have been merged at least once in the current release cycle.

After this date, packages will only be imported from Debian in this way by explicit request from a developer. (If the package needs to be modified for Ubuntu, or is not in Debian, then a developer can of course also upload it directly.)

Audiences to Consider

There are many audiences that attend to Ubuntu Freeze announcements, and specifically Debian Import Freeze. These include:

• The general public, embodied by those with interest, the press, a subset of users, etc.
• Testers and Enthusiasts, who may be aware that larger portions of Ubuntu are not installable prior to DIF
• Debian Developers, who may be aware that work done prior to DIF is surely going to reach Ubuntu, where work done thereafter may need additional coordination.
• Members of the Ubuntu Development community (including all of Prospective, Contributing, MOTU, and Core developers) who may have their workflows impacted by DIF.
• Members of ~ubuntu-dev, who may be expected to perform certain actions before or after the freeze, and may wonder how to request an exception.
• Archive Administrators, who may be unsure whether a given sync request (which may be overwriting Ubuntu changes, and serve the purpose of a merge) would require an exception.
• Release Managers, who may be unsure of the criteria for exceptions, or the appropriate reviewing body.

Implementation for Hardy

In the hardy release, Debian Import Freeze was introduced by a posting to ubuntu-devel-announce@lists.ubuntu.com, and followed by a thread on ubuntu-motu@lists.ubuntu.com, providing for the following exception process:

1. Document why the package should be merged (bugs are good for this)
2. Determine the rdepends, and plan any required transition (avoid these)
3. Get a member of ~ubuntu-dev (possibly including yourself) to agree
4. Upload all affected packages (should be less than 10) (may include sync requests)

Impact on direction of effort

If the development cycle could be described as consisting of several phases, firstly pulling in all the newest software available, secondly integrating this software and focusing on target features for the release, thirdly focusing on polish and bugfixing, and lastly pursuing a release process and addressing release-critical bugs, Debian Import Freeze may be a date used to separate the first and second phases of effort.

Relationship to merges to non-Debian upstreams

In addition to software derived from Debian, Ubuntu has over 2300 source packages not present in Debian unstable (and not indicated as removed from Debian). The process for updating these packages to upstream is not significantly different from the process of merging Ubuntu variation with Debian, yet how these packages are affected by this freeze is not specified.

Relationship to Syncs from Debian

While Ubuntu consists of nearly 17,000 sources package, with nearly 15,000 derived from Debian, only about 2000 of these packages have Ubuntu variation, and would be covered by the merge guidelines in Debian Import Freeze. There is no mention of whether syncs ought be completed for the remaining 13,000 packages, nor does the most recent freeze announcement specify whether such syncs would require a freeze exception.

Relationship to New Packages

In the Hardy release, the previous New Package inclusion deadline was aligned with other deadlines into FeatureFreeze. This is significantly later in the cycle than Debian Import Freeze, yet new packages may have a significant chance of introducing new bugs, which may impact other packages, as they have not received significant installation testing.

Balancing Upstream bugfixes vs. Upstream changes

For many upstreams, including Debian and some projects closer to Ubuntu (e.g. GNOME, Inkscape), there are a number of updated releases after Debian Import Freeze that specifically fix bugs. Depending on the difficulty inherent in being granted a freeze exception, developers may be discouraged from merging these updates into the distribution. Although changes upstream may well also introduce new and subtle bugs it is important that any selected freeze process provide for a reasonable balance between the advantages of pulling new upstreams and the risk of introducing new bugs for insufficiently tested features.

Potential differences between main and universe

Given the relationship between the volume of packages main(+restricted) and universe(+multiverse) components and the number of developers in ~ubuntu-core-dev and ~ubuntu-dev, packages in main tend to receive more frequent attention, and be more closely understood by specific developers, as well as receiving a higher volume of testing due to the popularity or importance of the selected packages. As a result, ceasing the import from Debian for main has less of an individual impact on the developers concerned than ceasing the import from Debian for universe, where many Debian updates represent bugfixes that are interesting to Ubuntu, and may even be Release Critical. Further, some packages in universe may receive no attention by Ubuntu developers for several successive releases, and it may be approprate to ensure that the Maintainer(s) of the package, who may have an interest in it in Ubuntu as well as Debian, are able to easily address any outstanding issues.

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