[Distutils] virtualenv and buildout integration ?

[Chris Withers]

Gary Poster wrote:
> 
> In the simplest case:
> 
> allowed-eggs-from-site-packages =
> 
> That means you don't allow any eggs from site packages.  So, this means 
> that if one of your direct or indirect dependencies is docutils, and 
> docutils is installed as an egg in your system, when the eggs for your 
> buildout are assembled, the system egg will be ignored, and buildout 
> will go on the hunt for one someplace else.  The typical result is that 
> the egg that it finds will be earlier in the site path, so it has 
> precedence in scripts and so on.

Ah, OK :-)

> Alternatively, consider this.
> allowed-eggs-from-site-packages =
>     lxml
> 
> That is, you only allow the lxml egg from site packages.  All the rest 
> will be ignored, as per the description above.

Hmm, okay, but what ensures the version of lxml found in site packages 
doesn't match the one required by the buildout?

> allowed-eggs-from-site-packages
>     This option interacts with the ``include-site-packages`` option in the
>     following ways.
> 
>     If ``include-site-packages`` is true, then
>     ``allowed-eggs-from-site-packages`` filters what eggs from 
> site-packages
>     may be chosen. 

Cool :-)

>     If ``include-site-packages`` is false, the value of
>     ``allowed-eggs-from-site-packages`` is irrelevant.

I'd suggest an exception should even be raised in this case...

> The next simplest answer is to use the new "include-site-packages = 
> false" option.  That's a tiny bit like using a virtualenv for your 
> buildout, in that you are using the system executable but a clean 
> site-packages.

Yep, this we like :-)

cheers,

Chris

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