[Numpy-discussion] Removing datetime support for 1.4.x series ?

[David Cournapeau]

On Thu, Feb 4, 2010 at 2:16 AM, Christopher Barker
<Chris.Barker at noaa.gov> wrote:
> David Cournapeau wrote:
>> Just so that there is no confusion: it is only about removing it for
>> 1.4.x, not about removing datetime altogether. It seems that datetime in
>> 1.4.x has few users,
>
> Of course it has few users -- it's brand new!

Yes, but that's my point: removing it has low impact, whereas breaking
ABI has a big impact.

>
>> whereas breaking ABI is a nuisance for many more
>> people. In particular, people who update NumPy 1.4.0 cannot use scipy or
>> matplotlib unless they build it by themselves as well - we are talking
>> about thousand of people at least assuming sourceforge numbers are accurate.
>
> Is it out of the question to make new builds of those?

But making new builds of those means that people will *have* to
upgrade NumPy if they want to use those builds. Or we would have to
keep different binaries for different versions of numpy. I think this
is insane. Nobody in their mind would do this.

>
> Anyway, ABI breakage will happen once in a while
>

My point is that it should not happen once in a while, only very
rarely, and after big consideration. It has tremendous cost for many
people: look at how many messages related to this we had on the ML in
the last few days. It is the atlas problem all over again, it makes us
look bad on "user-friendly platforms".

I don't know any good library which breaks ABI "once in a while" where
once in a while means several times a year.

>
> For my part - I tried 1.4, found it broke a few things, so I downgraded.
> Then a bit later, we decided we needed to build a few things anyway, so
> have now gone to 1.4 and rebuilt scipy, and out own Cython extensions.

Now think about users who cannot build their own extensions - I am
ready to bet we lose users for good every time this happens.

cheers,

David