[Numpy-discussion] numpy-1.11.0.dev0 windows wheels compiled with mingwpy available

[Nathaniel Smith]

On Mon, Oct 19, 2015 at 2:26 AM, Olivier Grisel
<olivier.grisel at ensta.org> wrote:
>> Is it possible to test this with py35 as well?
>
> Unfortunately not yet.
>
>> For MSVC, py35 requires a new compiler toolchain (VS2015) -- is that
>> something mingwpy/mingw-w64 can handle?
>
> I am pretty sure that mingwpy does not support Python 3.5 yet.

Correct.

> I don't know the status of the interop of mingw-w64 w.r.t. VS2015 but as far
> as I know it's not supported yet either. Once the issue is fixed at the
> upstream level, I think mingwpy could be rebuilt to benefit from the fix.

Upstream mingw-w64 doesn't support interop with any version of visual
studio that was released this millennium -- all the interop stuff is
new in mingwpy.

VS2015 had a major reorganization of how it handles runtime libraries,
so it's not quite so trivial as just adding support the same way as
was done for VS2008 and VS2010. Or rather, IIUC: we *could* just add
support the same way as before, but there are undocumented rules about
which parts of the new runtime are considered stable and which are
not, so if we did this willy-nilly then we might end up using some of
the "unstable" parts. And then in 2017 the Windows team does some
internal refactoring and pushes it out through windows update and
suddenly NumPy / R / Julia / git / ... all start segfaulting at
startup on Windows, which would be a disaster from everyone's point of
view. We've pointed this out to the Python team at Microsoft and
they've promised to try and put Carl and the relevant mingw-w64 folks
in touch with the relevant internal folks at MS to hopefully tell us
how to do this correctly... fingers crossed :-).

Aside from that, the main challenge for mingwpy in general is exactly
the issue of upstream support: if we don't get the interop stuff
pushed upstream from mingwpy to mingw-w64, then it will rot and break.
And upstream would love to have this interoperability as an officially
supported feature... but upstream doesn't consider what we have right
now to be maintainable, so they won't take it as is. (And honestly,
this is a reasonable opinion.) So what I've been trying to do is to
scrounge up some funding to support Carl and upstream doing this right
(the rough estimate is ~3 person-months of work).

The original goal was to get MS to pay for this, on the theory that
they should be cleaning up their own messes, but after 6 months of
back-and-forth we've pretty much given up on that at this point, and
I'm in the process of emailing everyone I can think of who might be
convinced to donate some money to the cause. Maybe we should have a
kickstarter or something, I dunno :-).

-n

-- 
Nathaniel J. Smith -- http://vorpus.org