[Numpy-discussion] c api deprecations with NPY_NO_DEPRECATED_API

[Paul Brossier]

On 11/03/2014 10:49, Nathaniel Smith wrote:
> On 11 Mar 2014 13:28, "Paul Brossier" <piem at piem.org
> <mailto:piem at piem.org>> wrote:
>> If I understand correctly, the current version is the one installed on
>> the user system. So using NPY_API_VERSION would mean "this code should
>> work with any version of numpy". I guess this is what I want (I would
>> even expect this to be the default setting). Did I miss something?
> 
> Using NPY_API_VERSION here means "this code will work with any version
> of numpy, *including ones that aren't released yet and might have
> arbitrary API changes*".
> 
> This is almost certainly not what you want.

Thanks for the clarification.

> The idea of the deprecation support is that it gives you a grace period
> to adapt to upcoming changes before they break your code. Suppose
> PyArray_foo is going to be removed in numpy 1.10. If we just removed it,
> your first warning would be when we release 1.10 and suddenly you have
> angry users who find your software no longer works. So the trick is that
> before we remove it entirely, we release 1.9, in which PyArray_foo is
> available if your NPY_DEPRECATED_API version is set to 1.8 or earlier,
> but not if it's set to 1.9. Your released versions thus continue to
> work, your users are happy, and the first person to encounter the
> problem is you, when you try to update your NPY_DEPRECATED_API to 1.9.
> You fix the problem, you make a new release, and then when 1.10 comes
> along everything works.
> 
> Moral: set NPY_DEPRECATED_API to match the highest numpy version you've
> tested.

I guess you meant NPY_NO_DEPRECATED_API?

Paul