Requirements

What is acceptable to SRU

Governance note: policy decisions on the broad criteria described in this section have historically been made by the Technical Board with individual review for compliance against these criteria performed by the SRU team. The authority to materially change these criteria therefore rests with the Technical Board, and not the SRU team. If, in the opinion of the SRU team, a proposed update does not meet these criteria, then the SRU will be rejected, unless the Technical Board change the criteria, make a clarification or grant an exception.

Stable release updates will, in general, only be issued in order to fix high-impact bugs. Examples of such bugs include:

• Bugs which represent severe regressions from the previous release of Ubuntu. This includes packages which are totally unusable, like being uninstallable or crashing on startup.

• Bugs which may, under realistic circumstances, directly cause a loss of user data

• Updates that need to be applied to Ubuntu packages to adjust to changes in the environment, server protocols, web services, and similar, i.e. where the current version just ceases to work. Examples:

  • app-install-data-commercial is a package index which regularly needs to be adjusted to changes in the commercial package archive.

  • clamav needs regular updates to latest virus signatures

  • tor needs a newer version to still work with the current Tor network.

  • A library for a web service needs to be updated for changes to the web server API.

Other safe cases

In the following cases a stable release update is also applicable as they have a low potential for regressing existing installations but a high potential for improving the user experience, particularly for Long Term Support releases:

• Bugs which do not fit under above categories, but (1) have an obviously safe patch and (2) affect an application rather than critical infrastructure packages (like X.org or the kernel).

• For Long Term Support releases we regularly want to enable new hardware. Such changes are appropriate provided that we can ensure not to affect upgrades on existing hardware. For example, modaliases of newly introduced drivers must not overlap with previously shipped drivers. This also includes updating hardware description data such as udev keymaps, media-player-info, mobile broadband vendors, or PCI vendor/product list updates. To avoid regressions on upgrade, any such hardware enablement must first also be added to any newer supported Ubuntu release.

• For Long Term Support releases we sometimes want to introduce new features. They must not change the behaviour on existing installations (e. g. entirely new packages are usually fine). If existing software needs to be modified to make use of the new feature, it must be demonstrated that these changes are non-intrusive, have a minimal regression potential, and have been tested properly. To avoid regressions on upgrade, any such feature must then also be added to any newer supported Ubuntu release. Once a new feature/package has been introduced, subsequent changes to it are subject to the usual requirements of SRUs to avoid regressions.

• FTBFS (Fails To Build From Source) can also be considered. Please note that in main the release process ensures that there are no binaries which are not built from a current source. Usually those bugs should only go through SRU in conjunction with another bug fix.

• Autopkgtest failures should also normally go through SRU only in conjunction with other high-priority fixes affecting users at runtime, optionally by staging them. As an exception, when an SRU of one package will introduce a regression in the autopkgtests of another package, it is appropriate to do an autopkgtest-only SRU of the other package.

For new upstream versions of packages which provide new features, but don’t fix critical bugs, a backport should be requested instead.

New upstream microreleases

In some cases, when upstream fixes bugs, they do a new microrelease instead of just sending patches. If all of the changes are appropriate for an SRU by the criteria above, then it is acceptable (and usually easier) to just upload the complete new upstream microrelease instead of backporting the individual patches. Note that some noise introduced by autoreconf is okay, but making structural changes to the build system (such as introducing new library dependencies) is generally not.

For upstreams who have

• a reliable and credible test suite for assuring the quality of every commit or release,

• the tests are covering both functionality and API/ABI stability,

• the tests run during package build to cover all architectures,

• the package has an autopkgtest to run the tests in an Ubuntu environment against the actual binary packages,

it is also acceptable to upload new microreleases with many bug fixes without individual Launchpad bugs for each of them (~ubuntu-sru will make the final decision). The upstream QA process must be documented/demonstrated and linked from the SRU tracking bug. In other cases where such upstream automatic testing is not available, exceptions must still be approved by at least one member of the Ubuntu Technical Board.

Out of scope

• Bugs which may, under realistic circumstances, directly cause a security vulnerability are out of scope of this process [explanation]. See instead Security team’s Update Procedures for details of how these are handled.

General requirements for all SRUs

• The development release must already be fixed and its bug task marked “Fix Released”, unless the development release is not yet open, in which case the development release upload must be prepared, ready and documented [explanation].

• Changes must be minimal [explanation], unless at least one of the following cases apply:

  • The SRU is one of the documented special types and that type, by definition, requires a non-minimal upload.

  • There is a documented standing permission that permits non-minimal changes.

  • You provide full justification of why the case is special and our general policy should not apply, and this justification is accepted by the SRU team when they review your upload.

• Any fix or feature addition being made to one release must first be made to all future releases to prevent users regressing when they upgrade. This includes any interim non-LTS releases that are still supported [explanation]. Exceptions:

  • If there are two subsequent interim releases that are both current, then, as a compromise, additionally fixing only the most recent one is acceptable.

  • You cannot supply the resources to fix an interim non-LTS release, you have explicitly stated your intention to use this exception in the SRU documentation in the relevant bugs, you have marked the relevant bug tasks Won’t Fix, and an SRU team member accepts your upload on a case-by-case basis.

• The SRU Driver and (if there is one) the Sponsor must be subscribed to relevant SRU bugs.

Documentation

Bugs

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Launchpad bugs are used for SRU documentation. Stable series bug tasks against existing Launchpad bugs should be used, such that there is only one Launchpad bug per issue being fixed. Exceptionally a generic bug may exist for special SRUs that track the special state being sought that is not complete.

Examples for standard SRU bugs:

• “When I do X it crashes”

Examples for special SRU bugs:

• “Release X not available on Ubuntu stable releases”

All bugs linked from the upload must be public. If required information exists in private bugs that cannot be made public, you must first create a separate public bug report in Launchpad and use that to present the required information instead.

Keep in mind that certain packages can change source package names between releases. In that case, if the given bug applies to a different source package that replaced the old one in a later releases, this source package has to be added as ‘Also affecting’. Make sure that the development releases package has the bug fixed before proceeding.

• If a change (e.g. from upstream) is known to exceed the scope of a standing exception to regular requirements, this must be pointed out

Special cases that must be mentioned

• If package-specific SRU notes exist and/or a standing approval exists to deviate from regular SRU policy, link to them from the bug

• If it’s a special SRU type, mention which, and check the documentation for the special SRU type for any other documentation that must be supplied

• If the basis of the justification of the SRU depends on something other than a special SRU type or the user impact statement, then this justification must be made

User Impact

• The impact to users must be made clear, and form the basis of the justification of the SRU.

Test Plan

• Detailed instructions on how to reproduce the bug and verify that the updated package fixes the problem.

• If the instructions do not exercise the common use of the package, then further instructions on how to ensure that the package still works.

• If the instructions do not exercise risks found in the Risk Analysis, then further instructions on performing testing to mitigate those risks.

• All instructions must provide enough detail such that someone who is not familiar with the affected package can follow them. They must be unambiguous so that two different developers will follow the same actual steps. To a reasonable limit, there should not be ambiguity.

• The idea is that this is agreed at review/accept time, and then if followed and the results presented precisely, then there should be no blockers at release time. Subject to any concerns raised that were not documented as considered previously.

• Must use the package from -proposed and no third party software.

Risk Analysis

• “None” is not OK.

• What risks we assume always exist.

• What the real purpose of this section is.

• If an obvious risk is missing, then we cannot determine if it was considered and discounted, or it’s an omission, and therefore this is a blocker.

• Should feed back into the Test Plan.

Other Information

• It is helpful, but not required, to include an explanation of how the upload fixes this bug

Upload

[maybe this section could have a better name and it needs cleaning up generally]

[Insert specifics here: minimal changes, version number, what should be in the changelog, bug references, etc]

The upload must have the correct release in the changelog header, a detailed and user-readable changelog, and no other unrelated changes.

The version number does not conflict with any later and future version in other Ubuntu releases (the security policy document has a well-working scheme which can be used for SRUs.)

There is at least one reference to a Launchpad bug number in the changelog, using the LP: #NNNNNN convention, and the required documentation can be found there. Private bugs must not be referenced in the changelog.

Bug references in changelogs

When uploading a new upstream version of a package as an SRU, there may be bugs fixed in the new version which will not go through a manual per-bug verification process. It is acceptable to still reference these bugs in the changelog, so that users can know about the bugs that will be fixed as part of the update and so that the status of these bugs in Launchpad can be managed automatically when the update is released.

If you include such bug references in your changelog, you should state in the bug description that these bugs are not being verified because of the use of the exception process.

After the SRU has been accepted, you should then add the verification-done-<series> tag to these bugs.

Release

Before release, the following requirements must be met. Most of these are tracked automatically on the pending SRU report.

• All referenced bugs have a QA report in a bug comment explaining how the Test Plan was performed, what package version was tested, and what the overall result was (pass or fail).

• All referenced bugs have verification-done-<series> set, and the verification-needed-<series> and verification-failed-<series> tags are absent.

• No bugs are marked block-proposed-<series>, for example because they are held by staging.

• There are no packages that failed to build such that this is a regression over the previous build status.

• All autopkgtest failures have been investigated and a resolution provided [how-to].

• The minimum ageing period of seven days has passed since the package was accepted into -proposed.

• All relevant SRUs for subsequent series are already released [explanation].

• Any other concerns raised in the referenced bugs have been addressed.