Dropping Support for Python 2.6

Alex Gaynor agaynor at mozilla.com
Thu Apr 27 15:40:26 EDT 2017

Yes, it does. Using the CentOS6 docker image:

# yum install centos-release-scl
# yum install python27
# python --version
Python 2.6.6
# scl enable python27 -- python --version
Python 2.7.8


On Thu, Apr 27, 2017 at 3:36 PM, Gregory Szorc <gregory.szorc at gmail.com>

> Remind me: does CentOS 6 also have access? I know I was using the IUS
> repositories (https://ius.io/) to get 2.7 on both RHEL 6 and CentOS 6. I
> just can't remember why I used them over SCL.
> I think the fear people have with installing a python2.7 package is that
> it puts things in /usr and PATH and could potentially interfere with other
> parts of system operation. e.g. scripts that look for `python2.7` and
> `python2.6` and use the first available could switch to 2.7 once the
> package is installed. That's arguably a good thing. But if you have some
> machine collecting dust, sometimes keeping things the way they are is the
> safest/best outcome. So a minimally invasive, self-contained Mercurial
> package could be desirable.
> (For the record, I'd like to hear from users still on 2.6 so we can make
> an informed decision about how to support these distros.)
> On Thu, Apr 27, 2017 at 12:26 PM, Alex Gaynor <agaynor at mozilla.com> wrote:
>> FWIW, RHEL 6 supports SCL (Software Collection Libraries) so it's
>> possible to get a Python2.7 _from Red Hat_.
>> Alex
>> On Thu, Apr 27, 2017 at 3:23 PM, Gregory Szorc <gregory.szorc at gmail.com>
>> wrote:
>>> I think the time has come to make a decision about dropping support for
>>> Python 2.6.
>>> In [1], we already decided that supporting 2.6 on Windows made no sense.
>>> While I don't think we ever wrote a patch, support for 2.6 on Windows is
>>> effectively gone.
>>> Also in that thread, Facebook said they will stop caring about Python
>>> 2.6 no later than 2017-04-30. Facebook runs some internal CI that helps
>>> flush out upstream bugs. And once they drop 2.6 support on their end, I
>>> imagine it will be more difficult for them to contribute certain things to
>>> core because they require 2.7. I'd like to not inconvenience one of our
>>> largest source of contributions.
>>> In [2], Augie seemed to indicate that he supports 4.2 or 4.3 being the
>>> last release that supports Python 2.6.
>>> At this point in time, Python 2.6 is a constant thorn in our side to
>>> support. It is hampering efforts to modernize the code. This is making the
>>> Python 3 port more difficult than it could be. There are bugs and
>>> workarounds for 2.6 that are just plain ugly. Furthermore, Python 2.6 isn't
>>> a secure execution platform. It doesn't support modern TLS versions and
>>> features. Upstream CPython support has been dead since 2013. Only long term
>>> support distros like RedHat 6 continue to run and support Python 2.6.
>>> I'd like to formally propose making Mercurial 4.2 (the release scheduled
>>> for May 1) the last release that supports Python 2.6.
>>> I anticipate that dropping 2.6 support will only inconvenience users on
>>> certain, legacy Linux distributions and other *NIX operating systems in a
>>> similar boat. Of these, I'm willing to wager that we really only care about
>>> RHEL 6 and variants (like CentOS 6). If these users will be significantly
>>> inconvenienced by lack of Python 2.6 support, I propose we make it easy to
>>> produce a self-contained Mercurial RPM containing a bundled Python 2.7.
>>> e.g. `make docker-centos6`. The Python within would be installed to e.g.
>>> /usr/lib/mercurial and wouldn't interfere with system operation: only
>>> shebangs in `hg` and other Mercurial-related executables would reference
>>> it. If the *capability* of producing those RPMs from a source distribution
>>> is not enough, we can consider hosting those RPMs on
>>> www.mercurial-scm.org for direct download (read: we wouldn't operate a
>>> full RPM repository with metadata, just raw files).
>>> [1] https://www.mercurial-scm.org/pipermail/mercurial-devel/2017
>>> -March/094837.html
>>> [2] https://www.mercurial-scm.org/pipermail/mercurial-devel/2017
>>> -April/097074.html
>>> _______________________________________________
>>> Mercurial-devel mailing list
>>> Mercurial-devel at mercurial-scm.org
>>> https://www.mercurial-scm.org/mailman/listinfo/mercurial-devel
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