Django’s release process¶
Since version 1.0, Django’s release numbering works as follows:
- Versions are numbered in the form A.B or A.B.C.
- A is the major version number, which is only incremented for major changes to Django, and these changes are not necessarily backwards-compatible. That is, code you wrote for Django 1.2 may break when we release Django 2.0.
- B is the minor version number, which is incremented for large yet backwards compatible changes. Code written for Django 1.2 will continue to work under Django 1.3. Exceptions to this rule will be listed in the release notes.
- C is the micro version number, which is incremented for bug and security fixes. A new micro-release will be 100% backwards-compatible with the previous micro-release. The only exception is when a security issue can’t be fixed without breaking backwards-compatibility. If this happens, the release notes will provide detailed upgrade instructions.
- In some cases, we’ll make alpha, beta, or release candidate releases. These are of the form A.B alpha/beta/rc N, which means the Nth alpha/beta/release candidate of version A.B.
In Subversion, each Django release will be tagged under tags/releases. If it’s necessary to release a bug fix release or a security release that doesn’t come from the trunk, we’ll copy that tag to branches/releases to make the bug fix release.
Major releases (1.0, 2.0, etc.) will happen very infrequently (think “years”, not “months”), and will probably represent major, sweeping changes to Django.
Minor release (1.1, 1.2, etc.) will happen roughly every nine months – see release process, below for details.
These releases will contain new features, improvements to existing features, and such. A minor release may deprecate certain features from previous releases. If a feature in version A.B is deprecated, it will continue to work in version A.B+1. In version A.B+2, use of the feature will raise a DeprecationWarning but will continue to work. Version A.B+3 will remove the feature entirely.
So, for example, if we decided to remove a function that existed in Django 1.0:
- Django 1.1 will contain a backwards-compatible replica of the function which will raise a PendingDeprecationWarning. This warning is silent by default; you need to explicitly turn on display of these warnings.
- Django 1.2 will contain the backwards-compatible replica, but the warning will be promoted to a full-fledged DeprecationWarning. This warning is loud by default, and will likely be quite annoying.
- Django 1.3 will remove the feature outright.
Micro releases (1.0.1, 1.0.2, 1.1.1, etc.) will be issued at least once half-way between minor releases, and probably more often as needed.
These releases will be 100% compatible with the associated minor release, unless this is impossible for security reasons. So the answer to “should I upgrade to the latest micro release?” will always be “yes.”
Each minor release of Django will have a “release maintainer” appointed. This person will be responsible for making sure that bug fixes are applied to both trunk and the maintained micro-release branch. This person will also work with the release manager to decide when to release the micro releases.
At any moment in time, Django’s developer team will support a set of releases to varying levels. See the download page for the current state of support for each version.
The current development trunk will get new features and bug fixes requiring major refactoring.
Patches applied to the trunk will also be applied to the last minor release, to be released as the next micro release, when they fix critical problems:
- Security issues.
- Data-loss bugs.
- Crashing bugs.
- Major functionality bugs in newly-introduced features.
The rule of thumb is that fixes will be backported to the last minor release for bugs that would have prevented a release in the first place.
Security fixes will be applied to the current trunk and the previous two minor releases.
Documentation fixes generally will be more freely backported to the last release branch, at the discretion of the committer, and they don’t need to meet the “critical fixes only” bar. That’s because it’s highly advantageous to have the docs for the last release be up-to-date and correct, and the downside of backporting (risk of introducing regressions) is much less of a concern.
As a concrete example, consider a moment in time halfway between the release of Django 1.3 and 1.4. At this point in time:
- Features will be added to development trunk, to be released as Django 1.4.
- Critical bug fixes will be applied to a 1.3.X branch, and released as 1.3.1, 1.3.2, etc.
- Security fixes will be applied to trunk, a 1.3.X branch and a 1.2.X branch. They will trigger the release of 1.3.1, 1.2.1, etc.
- Documentation fixes will be applied to trunk, and, if easily backported, to the 1.3.X branch.
Long-term support (LTS) releases¶
Additionally, the Django team will occasionally designate certain releases to be “Long-term support” (LTS) releases. LTS releases will get security fixes applied for a guaranteed period of time, typically 3+ years, regardless of the pace of releases afterwards.
See the download page for the releases that have been designated for long-term support.
Django uses a time-based release schedule, with minor (i.e. 1.1, 1.2, etc.) releases every nine months, or more, depending on features.
After each release, and after a suitable cooling-off period of a few weeks, the core development team will examine the landscape and announce a timeline for the next release. Most releases will be scheduled in the 6-9 month range, but if we have bigger features to development we might schedule a longer period to allow for more ambitious work.
Each release cycle will be split into three periods, each lasting roughly one-third of the cycle:
Phase one: feature proposal¶
The first phase of the release process will be devoted to figuring out what features to include in the next version. This should include a good deal of preliminary work on those features – working code trumps grand design.
At the end of part one, the core developers will propose a feature list for the upcoming release. This will be broken into:
- “Must-have”: critical features that will delay the release if not finished
- “Maybe” features: that will be pushed to the next release if not finished
- “Not going to happen”: features explicitly deferred to a later release.
Anything that hasn’t got at least some work done by the end of the first third isn’t eligible for the next release; a design alone isn’t sufficient.
Phase two: development¶
The second third of the release schedule is the “heads-down” working period. Using the roadmap produced at the end of phase one, we’ll all work very hard to get everything on it done.
Longer release schedules will likely spend more than a third of the time in this phase.
At the end of phase two, any unfinished “maybe” features will be postponed until the next release. Though it shouldn’t happen, any “must-have” features will extend phase two, and thus postpone the final release.
Phase two will culminate with an alpha release.
Phase three: bugfixes¶
The last third of a release is spent fixing bugs – no new features will be accepted during this time. We’ll release a beta release about halfway through, and an rc complete with string freeze two weeks before the end of the schedule.
After a minor release (e.g. 1.1), the previous release will go into bug-fix mode.
A branch will be created of the form branches/releases/1.0.X to track bug-fixes to the previous release. Critical bugs fixed on trunk must also be fixed on the bug-fix branch; this means that commits need to cleanly separate bug fixes from feature additions. The developer who commits a fix to trunk will be responsible for also applying the fix to the current bug-fix branch. Each bug-fix branch will have a maintainer who will work with the committers to keep them honest on backporting bug fixes.
How this all fits together¶
Let’s look at a hypothetical example for how this all first together. Imagine, if you will, a point about halfway between 1.1 and 1.2. At this point, development will be happening in a bunch of places:
- On trunk, development towards 1.2 proceeds with small additions, bugs fixes, etc. being checked in daily.
- On the branch “branches/releases/1.1.X”, fixes for critical bugs found in the 1.1 release are checked in as needed. At some point, this branch will be released as “1.1.1”, “1.1.2”, etc.
- On the branch “branches/releases/1.0.X”, security fixes are made if needed and released as “1.0.2”, “1.0.3”, etc.
- On feature branches, development of major features is done. These branches will be merged into trunk before the end of phase two.