This change is about upgrading
python-django to version 2.0. The latest Django release drops support for Python 2, but a few Django apps packaged in Fedora do not yet support Python 3. A compatibility package will be provided for those.
- Name: Matthias Runge
- Name: Miro Hrončok
- Name: Petr Viktorin
- Email: <email@example.com>
- Release notes ticket: #77
The latest Django release 2.0 finally drops support for Python 2.7. Not all dependent applications in Fedora can keep up with Djangos pace. This change describes a way how to enable both, keeping 2.7 compatibility and also leveraging the latest version.
python-django package will be updated to 2.0, Python 2 subpackage(s) will be removed. A new compatibility
python2-django1.11 package will be created with Python 2 version of Django 1.11. The Django 1.11.x series is the last to support Python 2.7, it also has Long Term Support (supported until April 2020 by upstream). See the Django 2.0 release notes for details about Django compatibility with various Python versions.
python2-django1.11 package will obsolete
python2-django < 2 and
python-django < 2, but it will deliberately not provide either of those. This will render packages depending on
python(2)-django FTBFS (or broken runtime dependencies if they don't require Django at buildtime). This is intentional. If we don't do that, all Django packages in Fedora will just keep dragging the Legacy Python dependency chain forever. Package owners of Django applications requiring Python 2 will need to manually adjust their dependencies to use
python2-django1.11 or move to Python 3 only (this is preferred but not always possible). Package owners of Django libraries will need to coordinate this with package owners of the applications. The rule of thumb is: If the library is not required by an application (packaged in Fedora) that uses Legacy Python, remove the Python 2 subpackage (or retire the package, if it cannot support Python 3).
There will be packages that fail to build or have broken dependencies. Package owners shall fix those by the steps described above. Proposal owners will send dist-git Pull Requests or Bugzilla patches to help. Proven packager powers will be used to merge those after 14 days of no activity. The removal of leftover packages from Fedora will be coordinated with FESCo (for approval) and releng (for execution).
Most of the Django packages in Fedora are already Python 3 compatible.
Note that we are aware that naming the compatibility package
python2-django would make this entire change much easier. But we'd very much like to retire the entire Python 2 based Django ecosystem at this point already. Creating
python2-django1.11 and not providing
python2-django is a compromise. Also, we plan to provide it as a contingency plan if necessary, see bellow.
Benefit to Fedora
Fedora will be able to provide both: latest and current release of Django and also a fallback for applications, which do not support Python 3 yet.
This will also remove some legacy packages nobody is actively taking care of.
- Proposal owners: drop Python 2 subpackage(s) from
python-djangoto 2.0 (done) and package
python2-django1.11for Python 2 only (done).
- Django apps owners: Either update to Python 3 or use
python2-django1.11as a dependency.
- Django libraries owners: Either drop Python 2 subpackages (eventually retire the package if no subpackages are left) or use
python2-django1.11as a dependency for the python 2 subpackages iff those are needed by apps (the second option applies to
python2-django-taggingonly!). When removing subpackages, add proper Obosletes tags to their Python 3 counterparts. When orphaning entire packages, add Obosletes to the
- Release engineering: #7211 (a check of an impact with Release Engineering is needed)
- releng will help with bulk retirement of packages that fail to keep up with this proposal
- Policies and guidelines:
- Python packaging guidelines
- Documentation should be provided
List of packages requiring
python-django without having
django in their name:
python2-django-tagging, the only library that needs to have py2 version)
The obsoletes added to
python2-django1.11 and others should make the upgrade work seamlessly.
How To Test
You should be able to install two web-apps, one requiring
python2-django1.11 and one requiring
python3-django. (TODO: provide actual package names)
- dnf install (package 1)
- see python2-django1.11 is installed as dependency
- run that package
- dnf install (package 2)
- verify python3-django is installed as dependency
- package 1 still works
- package 2 works as well
- dnf remove package 1
- package 2 still works
Users using RPM installed Django to develop Django apps might be affected by this change. We shall recommend either using venvs or using Python 3. See the developer portal, we are already recommending both.
- Contingency mechanism: (What to do? Who will do it?) Proposal owners will add
python-djangovirtual provides to
python2-django1.11if everything goes south.
- Contingency deadline: beta freeze
- Blocks release? No
- Blocks product? No