[Python-Dev] Moving Python 3.5 on Windows to a new compiler (original) (raw)

Brian Curtin brian at python.org
Fri Jun 6 20:49:24 CEST 2014

On Fri, Jun 6, 2014 at 10:41 PM, M.-A. Lemburg <mal at egenix.com> wrote:

On 06.06.2014 20:25, Brian Curtin wrote:

On Fri, Jun 6, 2014 at 10:19 PM, Chris Angelico <rosuav at gmail.com> wrote:

On Sat, Jun 7, 2014 at 4:12 AM, Steve Dower <Steve.Dower at microsoft.com> wrote:

Chris Angelico wrote:

On Sat, Jun 7, 2014 at 1:41 AM, Steve Dower <Steve.Dower at microsoft.com> wrote:

What this means for Python is that C extensions for Python 3.5 and later can be built using any version of MSVC from 14.0 and later.

Oh, if only this had been available for 2.7!! Actually... this means that 14.0 would be a good target for a compiler change for 2.7.x, if such a change is ever acceptable. Maybe, but I doubt it will ever be acceptable :) Well, there were discussions. Since Python 2.7's support is far exceeding the Microsoft promise of support for the compiler it was built on, there's going to be a problem, one way or the other. I don't know how that's going to end up being resolved. We're going to have to change it at some point, otherwise we're going to have people in 2018 scrambling to find VS2008, which will be 35 versions too old by then. No matter what we do here, we're going to have a tough PR situation, but we have to make something workable. I'd rather cause a hassle than outright kill extensions. I would probably prefer we aim for VS 14 for 3.5, and then explore making the same change for the 2.7.x release that comes after 3.5.0 comes out. Lessons learned and all that. Are you sure that's an option ? Changing the compiler the stock Python from python.org is built with will most likely render existing Python extensions built for 2.7.x with x < (release that comes after 3.5.0) broken, so users and installation tools will end up having to pay close attention to the patch level version of Python they are using... which is something we wanted to avoid after we ran into this situation with 1.5.1 and 1.5.2 a few years ago.

None of the options are particularly good, but yes, I think that's an option we have to consider. We're supporting 2.7.x for 6 more years on a compiler that is already 6 years old. Something less than awesome for everyone involved is going to have to happen to make that possible.

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