[Python-Dev] PEP 408 -- Standard library preview package (original) (raw)

Nick Coghlan ncoghlan at gmail.com
Sat Jan 28 02:37:37 CET 2012

On Sat, Jan 28, 2012 at 8:54 AM, Barry Warsaw <barry at python.org> wrote:

I think the OS vendor problem is easier with an application that uses some PyPI package, because I can always make that package available to the application by pulling in the version I care about.  It's harder if a newer, incompatible version is released upstream and I want to provide both, but I don't think preview addresses that.  A robust, standard approach to versioning of modules would though, and I think would better solve what preview is trying to solve.

I'd be A-OK with an explicit requirement that any module shipped in preview must have a third-party supported multi-version compatible alternative on PyPI. (PEP 2 actually pretty much says that should be the case, but making it mandatory in the preview case would be a good idea).

As an OS vendor, you'd then be able to say: "Don't use preview, since that will cause problems when we next upgrade the system Python. Use the PyPI version instead."

Then the stdlib docs for that module (while it is in preview) would say "If you are able to easily use third party packages, package offers this API for multiple Python versions with stronger API stability guarantees. This preview version of the module is for use in environments that specifically target a single Python version and/or where the use of third party packages outside the standard library poses additional complications beyond simply downloading and installing the code."

Cheers, Nick.

-- Nick Coghlan   |   ncoghlan at gmail.com   |   Brisbane, Australia

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