[Distutils] The "incompatible versions" problem

[Lennart Regebro]

On Fri, Nov 27, 2009 at 13:05, Chris Withers <chris at simplistix.co.uk> wrote:
> Hi All,
>
> Do you guys on this lists have any ideas how packages can indicate to
> package managers like setuptools could indicate that if they are required by
> another package, that requirement must be for greater than a certain
> version?
>
> This stems from the "backwards compatibility" discussion for zope.interface
> here:
>
> https://mail.zope.org/pipermail/zope-dev/2009-November/038417.html
>
> Off the top of my head, zope.component could spell it's requirement as:
>
> def setup(
>  ...
>  incompatible_with='<4.0'
>  )
>
> Whereby, setuptools would raise an exception if the following packages were
> installed:
>
> def setup(
>  ...
>  install_requires=['zope.component']
>  )

I think this is the problem. I understand what you mean, but it's not
obvious to me at all that this should raise an error in this
situation. But yet, for your suggestion to work, it has to. In
practice, that means that you, to use zope.component >= 4.0, must give
a version number. But even when an API changes, it may be possible to
support both versions. And that would then be impossible to do in this
case.

I suspect it's an unsolvable problem. It's too open ended.
-- 
Lennart Regebro: Python, Zope, Plone, Grok
http://regebro.wordpress.com/
+33 661 58 14 64