Revision as of 14:02, 12 December 2017

Django 2.0

Summary

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.

Owner

Name: Matthias Runge
Name: Miro Hrončok
Email: <mrunge@matthias-runge.de> <mhroncok@redhat.com>
Release notes owner:

Current status

Targeted release: Fedora 28
Last updated: 2017-12-12
Tracker bug: <will be assigned by the Wrangler>

Detailed Description

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.

The 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.

Note that whether this will be a Python 2 only package or rather python-django1.11 SRPM creating both python2-django1.11 and python3-django1.11 packages is yet to be decided.

The new 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 tehy 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).

Most of the Django packages in Fedora are already Python 3 compatible.

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.

Scope

Proposal owners: drop Python 2 subpackage(s) from python-django, upgrade python-django to 2.0 and package python2-django1.11 for Python 2 only or python-django1.11 for both Pythons (yet to be decided).

Django apps owners: Either update to Python 3 or use python2-django1.11 as a dependency.

Django libraries owners: Either drop Python 2 subpackages (eventually retire the package if no subpackages are left) or use python2-django1.11 as a dependency for the python 2 subpackages iff those are needed by apps. When removing subpackages, add proper Obosletes tags to their Python 3 counterparts. When orphaning entire packages, add Obosletes to the python3-django package.

Release engineering: #Releng issue number (a check of an impact with Release Engineering is needed)
- List of deliverables: N/A (not a System Wide Change)

Policies and guidelines:
- Python packaging guidelines
- Documentation should be provided

Trademark approval: N/A (not needed for this Change)

List of packages requiring python2-django/ python-django without having django in their name:

Upgrade/compatibility impact

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

User Experience

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 Plan

Contingency mechanism: (What to do? Who will do it?) Add python2-django and python-django virtual provides to python2-django1.11.
Contingency deadline: beta freeze
Blocks release? No
Blocks product? No

Documentation

TBD

Release Notes

TBD

@@ Line 62: / Line 62: @@
 == Scope ==
-* Proposal owners: drop Python2 subpackage from python-django, upgrade python-django to Django-2.0 and package Django-1.11.x for Python2 only.
+* '''Proposal owners:''' drop Python 2 subpackage(s) from {{package|python-django}}, upgrade {{package|python-django}} to 2.0 and package {{package|python2-django1.11}} for Python 2 only or {{package|python-django1.11}} for both Pythons (yet to be decided).
 <!-- What work do the feature owners have to accomplish to complete the feature in time for release?  Is it a large change affecting many parts of the distribution or is it a very isolated change? What are those changes?-->
-* Other developers: Other developers, whose applications do work with Python3 and Django 2.0 will need to change the requirement to python3-django.
+* '''Django apps owners:''' Either update to Python 3 or use {{package|python2-django1.11}} as a dependency.
+* '''Django libraries owners:''' Either drop Python 2 subpackages (eventually retire the package if no subpackages are left) or use {{package|python2-django1.11}} as a dependency for the python 2 subpackages iff those are needed by apps. When removing subpackages, add proper Obosletes tags to their Python 3 counterparts. When orphaning entire packages, add Obosletes to the {{package|python3-django}} package.
 * Release engineering: [https://pagure.io/releng/issues #Releng issue number] (a check of an impact with Release Engineering is needed) <!-- REQUIRED FOR SYSTEM WIDE AS WELL AS FOR SELF CONTAINED CHANGES -->
@@ Line 81: / Line 83: @@
 * Trademark approval: N/A (not needed for this Change)
 <!-- If your Change may require trademark approval (for example, if it is a new Spin), file a ticket ( https://fedorahosted.org/council/ ) requesting trademark approval from the Fedora Council. This approval will be done via the Council's consensus-based process. -->
+List of packages requiring  {{package|python2-django}}/ {{package|python-django}} without having <code>django</code> in their name:
+* {{package|cobbler-web}}
+* {{package|fts-monitoring}}
+* {{package|gramps-webapp}}
+* {{package|graphite-web}}
+* {{package|pony}}
+* {{package|pulp-server}}
+* {{package|python2-kobo-admin}}
+* {{package|python2-kobo-hub}}
+* {{package|python2-pelican}}
+* {{package|python2-testfixtures-tests}}
+* {{package|python2-whitenoise}}
+* {{package|python2-xmlrunner}}
 == Upgrade/compatibility impact ==
 <!-- What happens to systems that have had a previous versions of Fedora installed and are updated to the version containing this change? Will anything require manual configuration or data migration? Will any existing functionality be no longer supported? -->
-<!-- REQUIRED FOR SYSTEM WIDE CHANGES -->
+The obsoletes added to {{package|python2-django1.11}} and others should make the upgrade work seamlessly.
-N/A (not a System Wide Change)
 == How To Test ==
@@ Line 104: / Line 120: @@
 <!-- REQUIRED FOR SYSTEM WIDE CHANGES -->
-You should be able to install two web-apps, one requiring python2-django and one requiring python3-django. (TODO: provide actual package names)
+You should be able to install two web-apps, one requiring {{package|python2-django1.11}} and one requiring {{package|python3-django}}. (TODO: provide actual package names)
 # dnf install (package 1)
-# see python2-django is installed as dependency
+# see python2-django1.11 is installed as dependency
 # run that package
 # dnf install (package 2)
@@ Line 118: / Line 134: @@
 <!-- If this change proposal is noticeable by its target audience, how will their experiences change as a result?  Describe what they will see or notice. -->
 <!-- REQUIRED FOR SYSTEM WIDE CHANGES -->
-N/A (not a System Wide Change)
-== Dependencies ==
-<!-- What other packages (RPMs) depend on this package?  Are there changes outside the developers' control on which completion of this change depends?  In other words, completion of another change owned by someone else and might cause you to not be able to finish on time or that you would need to coordinate?  Other upstream projects like the kernel (if this is not a kernel change)? -->
-<!-- REQUIRED FOR SYSTEM WIDE CHANGES -->
+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 [https://developer.fedoraproject.org/tech/languages/python/django-installation.html recommending both].
-N/A (not a System Wide Change)
 == Contingency Plan ==
 <!-- If you cannot complete your feature by the final development freeze, what is the backup plan?  This might be as simple as "Revert the shipped configuration".  Or it might not (e.g. rebuilding a number of dependent packages).  If you feature is not completed in time we want to assure others that other parts of Fedora will not be in jeopardy.  -->
-* Contingency mechanism: (What to do?  Who will do it?) N/A (not a System Wide Change)  <!-- REQUIRED FOR SYSTEM WIDE CHANGES -->
+* Contingency mechanism: (What to do?  Who will do it?) Add <code>python2-django</code> and <code>python-django</code> virtual provides to {{package|python2-django1.11}}.
 <!-- When is the last time the contingency mechanism can be put in place?  This will typically be the beta freeze. -->
-* Contingency deadline: N/A (not a System Wide Change)  <!-- REQUIRED FOR SYSTEM WIDE CHANGES -->
+* Contingency deadline: beta freeze
 <!-- Does finishing this feature block the release, or can we ship with the feature in incomplete state? -->
-* Blocks release? N/A (not a System Wide Change), Yes/No <!-- REQUIRED FOR SYSTEM WIDE CHANGES -->
+* Blocks release? No
-* Blocks product? product <!-- Applicable for Changes that blocks specific product release/Fedora.next -->
+* Blocks product? No
 == Documentation ==
 <!-- Is there upstream documentation on this change, or notes you have written yourself?  Link to that material here so other interested developers can get involved. -->
-<!-- REQUIRED FOR SYSTEM WIDE CHANGES -->
+TBD
-N/A (not a System Wide Change)
 == Release Notes ==
@@ Line 148: / Line 158: @@
 Release Notes are not required for initial draft of the Change Proposal but has to be completed by the Change Freeze.
 -->
+TBD
 [[Category:ChangePageIncomplete]]

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