[Distutils] PEP425 - Wheel Binary Package Compatibility

Nick Coghlan ncoghlan at gmail.com
Thu Oct 30 00:57:03 CET 2014

On 30 Oct 2014 07:20, "Marcus Smith" <qwcode at gmail.com> wrote:
> yes, I'm partial to a solution like this prior to wheel 2.0 (that I
imagine would support additional/custom tags)

+1 for being able to add additional custom platform tags in the file naming
convention from me as well. As Marcus noted earlier, even if you set up
distro specific indexes currently, there's nothing built into the tooling
to keep you from trying to install (e.g.) a Fedora 21 wheel on RHEL or
CentOS 5 (which is highly unlikely to work, given that the core ABIs in
RHEL/CentOS 5 are 7 or 8 years old at this point).

We'd be highly unlikely to flip the switch from "experimental service, use
at your own risk" to "fully supported Fedora feature" while that's still
the case.

With arbitrary platform tags, we could inject that into the wheel filenames
as part of the build process, and then again when invoking pip.

That opens things up for us to figure out how to best flag compatibility on
the distro side, without committing to a specific approach upstream (not
yet, anyway).

An alternative approach would be to add an "additional wheel suffix"
setting for pip that allowed us to have names with endings like ".fc21.whl"
or ".el7.whl" recognised as valid wheel files.

I'm not that worried about the exact details though - the main feature I'd
like is the ability to create wheel files that pip will ignore by default,
but will accept if I specifically tell it what to look for.


> On Wed, Oct 29, 2014 at 1:46 PM, Daniel Holth <dholth at gmail.com> wrote:
>> I've always thought people might like to have a custom platform tag or
>> otherwise customize the supported list in a configuration file loaded
>> by pep425tags. Then you could create wheels called
>> somewheel-4.0-py33-none-30caa8a209d6.whl (choose your own random
>> string). Only a pip with a matching config would pay any attention to
>> those wheels. That way we could help people manage their internal
>> deployments without falsely advertising that we've solved the binary
>> incompatibility feature baked into every Linux distribution.
>> On Wed, Oct 29, 2014 at 3:52 PM, Donald Stufft <donald at stufft.io> wrote:
>> >
>> > On Oct 29, 2014, at 2:36 PM, Marcus Smith <qwcode at gmail.com> wrote:
>> >
>> >
>> >> This is the kind of direction we're also exploring for Fedora & EPEL:
>> >> setting up a distro specific devpi instance so we can automatically
>> >> distro compatible wheel files, as well as separating the distro level
>> >> licencing and preliminary security review step from the step of
>> >> in a language independent format. (I need to set up a curated PyPI
>> >> for work anyway, and since I work at Red Hat, and the Fedora
community are
>> >> open to the idea, we're working on it upstream rather than inside the
>> >> firewall)
>> >
>> >
>> > Btw, I've been doing this at my company, that is maintaining separate
>> > indexes per platform we need (in our case, cent5 and cent6).
>> > One problem here is that it's possible for pip download caches to get
>> > "corrupted" with the wrong distributions (i.e. the incompatible ones),
>> > the distributions are not distinguishable by name
>> > Would Fedora really consider releasing a public service where there
>> > release is not represented in the distribution name? or would you be
>> > to get more tagging spec'd out in Wheel 2.0 first?
>> >
>> > P.S.  In looking at the PEP425/427 specs again, I'm slightly confused
>> > the "build tag".  It's barely covered, but I can imagine using that
>> > to distinguish dists, assuming pip support was added, alhough it's
>> > to start with a number, which doesn't seem to fit the use case we'd
>> >
>> >
>> > _______________________________________________
>> > Distutils-SIG maillist  -  Distutils-SIG at python.org
>> > https://mail.python.org/mailman/listinfo/distutils-sig
>> >
>> >
>> > It’s a build number, it’s used incase you need to rebuild a Wheel
using the
>> > same source files.
>> >
>> > ---
>> > Donald Stufft
>> > PGP: 7C6B 7C5D 5E2B 6356 A926 F04F 6E3C BCE9 3372 DCFA
>> >
>> >
>> > _______________________________________________
>> > Distutils-SIG maillist  -  Distutils-SIG at python.org
>> > https://mail.python.org/mailman/listinfo/distutils-sig
>> >
> _______________________________________________
> Distutils-SIG maillist  -  Distutils-SIG at python.org
> https://mail.python.org/mailman/listinfo/distutils-sig
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