[Distutils] PEP 517 again

[xoviat]

Donald,


This was your work in https://github.com/pypa/pip/pull/2169. Unfortunately
the comments were quite sparse.

2017-09-02 18:25 GMT-05:00 xoviat <xoviat at gmail.com>:

> One more issue that has come up is that "--no-user-cfg" seems to be passed
> to the egg_info invocation if the "isolated" parameter is enabled. I don't
> understand what this does, but it is again not defined in the PEP 517
> interface. Should we always pass this parameter or should we never pass it?
>
> 2017-09-02 14:42 GMT-05:00 Donald Stufft <donald at stufft.io>:
>
>>
>> On Sep 1, 2017, at 2:30 PM, Chris Barker <Chris.Barker at noaa.gov> wrote:
>>
>> On Thu, Aug 31, 2017 at 9:23 PM Nick Coghlan <ncoghlan at gmail.com> wrote:
>>
>> since it
>>> doesn't reliably distinguish between "this cached wheel was downloaded
>>> from a repository" and "this wheel was generated locally with a
>>> particular version of Python".
>>
>>
>> It shouldn't have to. sigh.
>>
>>>
>>  PEP 517 deliberately doesn't let
>>> frontends do that as part of the initial build process (instead, if
>>> they want to adjust the tags, they need to do it as a post-processing
>>> step).
>>>
>>> Since PEP 517 breaks the current workaround for the caching scheme
>>> being inaccurate, the most suitable response is to instead fix pip's
>>> caching scheme to use a two tier local cache:
>>
>>
>> I'm still confused -- if setuptools ( invoked  by pip) is producing
>> incorrectly named wheels -- surely that's a bug-fix/workaround that should
>> go into setuptools?
>>
>> If the build is being run by pip, then doesn't setuptools have all the
>> info about the system that pip has?
>>
>>
>>
>>
>> Someone building a wheel for distribution is likely intimately aware of
>> that project, and can take care to ensure that the wheel is built in such a
>> way that it is giving people the most optimal behavior. Pip is auto
>> building wheels without human intervention, and as such there is nobody
>> there to make sure that we’re not accidentally creating a too-broad wheel,
>> so we want to ensure that we have some mechanism in place for not re-using
>> the wheel across boundaries that might cause issues.
>>
>>
>>
>> we also have plenty of PyPI users that
>>> explicitly *opt out* of using publisher-provided pre-built binaries.
>>> While Linux distributions are the most common example (see [1] for
>>> Fedora's policy, for example), we're not the only ones that have that
>>> kind of rule in place.
>>
>>
>> But this is an argument for why pypi should host sdists, and the build
>> tools should build sdists, but not why pip should auto-build them.
>>
>>>
>> Condo-forge, for example, almost always builds from source -- sometimes
>> an sdist
>> from pypi, sometimes a source distribution from github or wherever the
>> package is hosted. And sometimes from a git tag ( last resort).
>>
>>
>>
>> Pip supports more systems than Conda does, and we do that by relying on
>> auto building support. Pip supports systems that don’t have a wheel
>> compatibility tag defined for them, and for which we’re unlikely to ever
>> have any wheels published for (much less wide spread). It’s pretty easy to
>> cover Windows/macOS/Some Linux systems, but when you start talking about
>> FreeBSD, OpenBSD, Solaris, AIX, HP-UX, etc then the long tail gets
>> extremely long.
>>
>> Pip works in all these situations, and it does so by relying on building
>> from source.
>>
>>
>>
>> Do the Linux distros use pip to build their packages?
>>
>>
>>
>> Not that I am aware of.
>>
>>
>> I tried to do that with conda-packages, and failed due to pip's caching
>>  behavior-- it probably would have worked fine in production, but when I
>> was developing the build script, I couldn't reliably get pip to ignore
>> cached wheels from previous experimental builds.
>>
>>
>>
>> Adding —no-cache-dir disables all of pip’s caching.
>>
>> —
>> Donald Stufft
>>
>>
>>
>>
>> _______________________________________________
>> Distutils-SIG maillist  -  Distutils-SIG at python.org
>> https://mail.python.org/mailman/listinfo/distutils-sig
>>
>>
>
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