[Cython] Preparing Cython 3.0 with breaking changes

[Erik Bray]

On Sat, Aug 18, 2018 at 9:19 AM Stefan Behnel <stefan_ml at behnel.de> wrote:
>
> Hi all,
>
> following the versioning discussion, I created a milestone to collect
> (breaking) changes that should go into the future Cython 3.0 release.
>
> https://github.com/cython/cython/milestone/58
>
> While a major version change is a good time to fix things that, in
> retrospect, have led us too far in the wrong direction, we are not planning
> to remove the support for existing code any time soon that relies on the
> current semantics. For now, it looks like the major breaking changes will
> be to directive defaults, which means that setting them explicitly to their
> current configuration (e.g. in setup.py) should keep code working across
> Cython releases.
>
> Feedback welcome.

Hi Stefan,

Not related to the Cython language itself, but it would be good, as
related to issues like #1514 [1] and #2531 [2] to rip out a lot of the
old disutils-related code, which would be a breaking change.  Perhaps
this could be done in a way that isn't *too* breaking, such as leaving
behind some stubs, as this might also require some changes to
setuptools (which I can help make happen).

Of course, none of this should happen without something better to
replace it, along the lines that we discussed in Cernay.  I still have
my notes from our talk about that and will try to write up a summary
(which I should have done back then, but oh well).

Just thought I'd mention that a another potential "breaking change"
that might be worth adding to the list, and I don't think it will
break much if handled with a bit of care.

[1] https://github.com/cython/cython/issues/1514
[2] https://github.com/cython/cython/issues/2531