[posted to c.l.py.announce and c.l.py; followups to c.l.py; cc'd to python-dev]
[Barry, please update Post-History]
Okay, here's the next version of PEP 6:
PEP: 6 Title: Bugfix Releases Version: $Revision: 1.3 $ Author: firstname.lastname@example.org (Aahz) Status: Draft Type: Informational Created: 15-Mar-2001 Post-History: 15-Mar-2001
Python has historically had only a single fork of development, with releases having the combined purpose of adding new features and delivering bug fixes (these kinds of releases will be referred to as "feature releases"). This PEP describes how to fork off patch releases of old versions for the primary purpose of fixing bugs.
This PEP is not, repeat NOT, a guarantee of the existence of patch releases; it only specifies a procedure to be followed if patch releases are desired by enough of the Python community willing to do the work.
With the move to SourceForge, Python development has accelerated. There is a sentiment among part of the community that there was too much acceleration, and many people are uncomfortable with upgrading to new versions to get bug fixes when so many features have been added, sometimes late in the development cycle.
One solution for this issue is to maintain the previous feature release, providing bugfixes until the next feature release. This should make Python more attractive for enterprise development, where Python may need to be installed on hundreds or thousands of machines.
Patch releases are required to adhere to the following restrictions:
1. There must be zero syntax changes. All .pyc and .pyo files must work (no regeneration needed) with all patch releases forked off from a feature release.
2. There must be zero pickle changes.
3. There must be no incompatible C API changes. All extensions must continue to work without recompiling in all patch releases in the same fork as a feature release.
Breaking any of these prohibitions requires a BDFL proclamation (and a prominent warning in the release notes).
Starting with Python 2.0, all feature releases are required to have a version number the form X.Y; patch releases will always be of the form X.Y.Z.
The current feature release under development is referred to as release N; the just-released feature version is referred to as N-1.
The process for managing patch releases is modeled in part on the Tcl system .
The Patch Czar is the counterpart to the BDFL for patch releases. However, the BDFL and designated appointees retain veto power over individual patches.
As individual patches get contributed to the feature release fork, each patch contributor is requested to consider whether the patch is a bugfix suitable for inclusion in a patch release. If the patch is considered suitable, the patch contributor will mail the SourceForge patch (bugfix?) number to the maintainers' mailing list.
In addition, anyone from the Python community is free to suggest patches for inclusion. Patches may be submitted specifically for patch releases; they should follow the guidelines in PEP 3 .
The Patch Czar decides when there are a sufficient number of patches to warrant a release. The release gets packaged up, including a Windows installer, and made public. If any new bugs are found, they must be fixed immediately and a new patch release publicized (with an incremented version number).
Patch releases are expected to occur at an interval of roughly one month. In general, only the N-1 release will be under active maintenance at any time.
Patch Czar History
Moshe Zadka (email@example.com) is the Patch Czar for 2.0.1.
Issues To Be Resolved
What is the equivalent of python-dev for people who are responsible for maintaining Python? (Aahz proposes either python-patch or python-maint, hosted at either python.org or xs4all.net.)
Does SourceForge make it possible to maintain both separate and combined bug lists for multiple forks? If not, how do we mark bugs fixed in different forks? (Simplest is to simply generate a new bug for each fork that it gets fixed in, referring back to the main bug number for details.)
This PEP started life as a proposal on comp.lang.python. The original version suggested a single patch for the N-1 release to be released concurrently with the N release. The original version also argued for sticking with a strict bugfix policy.
Following feedback from the BDFL and others, the draft PEP was written containing an expanded patch release cycle that permitted any previous feature release to obtain patches and also relaxed the strict bugfix requirement (mainly due to the example of PEP 235 , which could be argued as either a bugfix or a feature).
Discussion then mostly moved to python-dev, where BDFL finally issued a proclamation basing the Python patch release process on Tcl's, which essentially returned to the original proposal in terms of being only the N-1 release and only bugfixes, but allowing multiple patch releases until release N is published.
This document has been placed in the public domain.
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