getting python version used by another port

[Titus von Boxberg]

Am 28.11.2011 um 17:24 schrieb Jeremy Lavergne:

>> Or is it necessary to create py27-hgsubversion and have py26-hgsubversion
>> being replaced_by the former?
> 
> If mercurial only supports 2.7 and not 2.6 then I'd switch everything out
> with replaced_by. If both work, then two separate ports are needed.

Mercurial supports (according to it's web page) 2.4 through 2.7

In the Portfile there is the line
python.default_version 27
I didn't find that documented and could not figure out what exactly it means.
Is it either
- PortGroup python now knows that there is a dependency on exactly this version?
- or PortGroup python knows somehow automagically that some version in the 2 series
  is sufficient?

However, you only implicitely answered the original question:
So there is no canonical way to figure out the python version actually
used by another port?

Regards
Titus