[Distutils] multiple backports of ipaddress and a world of pain

[Nick Coghlan]

On 19 February 2016 at 16:59, Chris Withers <chris at simplistix.co.uk> wrote:

> Hi Nick,
>
> On 18/02/2016 13:32, Nick Coghlan wrote:
>
> On 17 February 2016 at 04:37, Chris Withers <chris at simplistix.co.uk>
> wrote:
>
>>
>> So, RHEL7, for worse or worse, ships with Python 2.7.5.
>
>
> It's 2.7.5 + important security backports, so any package that relies on
> PEP 466 features like ssl.create_default_context() should be fine in 7.2+.
> (You can also switch on default certificate verification if you want it:
> https://access.redhat.com/articles/2039753 )
>
> The company I'm with at the moment is one of the more aggressive operating
> system release followers I've worked with or for, and even we're not on 7.2
> yet!
>


Aye, being on 7.x at all already means they're doing better than a lot of
folks. If fast adoption of new distro versions was entirely typical we
wouldn't still be having to encourage people to stop running their own
applications in the RHEL 6 system Python :)


> <multiple ipaddress backports>
>
> It looks like you found a resolution to this part of the problem, but
> those dependencies should only be needed on 7.0 and 7.1
>
> Unfortunately, I missed this use case when PEP 508 was being defined, so
> there's currently no capability for Python level dependencies to be
> conditional on the presence or absence of particular attributes in other
> modules :(
>
> Not sure that's such a biggie here, I'd more like to see pip at least
> notice that it's trying to install two files into the same location.
>

It's mainly a note to myself that there's a current gap in our backporting
story there, since it means folks *can't* currently do ssl module feature
detection at installation time to decide if they need PyOpenSSL as a
dependency or not. At the moment that only impacts RHEL 7.2+, but if PEP
493 gets accepted, the omission may end up affecting other LTS Linux
distros as well.

Cheers,
Nick.

-- 
Nick Coghlan   |   ncoghlan at gmail.com   |   Brisbane, Australia
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://mail.python.org/pipermail/distutils-sig/attachments/20160220/f768d967/attachment.html>