How can variant B imply variant A?

[Mojca Miklavec]

On Wed, Aug 22, 2012 at 3:29 PM, Michael Dickens  wrote:
> Hi Mojca - I assume I was included because the qt4-mac / gnuplot issue you
> described (as forwarded below)?

Exactly.

> If I understand what you wrote, I really
> don't see that as an issue since it was a current version of qt4-mac and an
> archived version of gnuplot.  I think the vast majority of users will not be
> encountering this issue; it'll be just a handful of developers and hackers,
> and they will have "asked for it" :)  I'm not sure there's any reasonable
> way to guarantee that a current port is compatible with an older, archived
> version of another port; just too many possibilities of things that could go
> wrong there.

I totally agree with that point of view. (I was just a bit less explicit.)

> Or, maybe I don't understand what the issue really is, or its
> importance? - MLD

I wrote that for two reasons (apart from being bitten by it in the
morning). The first reason is that user may legally do the following:
- install "qt4-mac +framework"
- install another port with default dependency on qt4-mac which was
built with buildbot and depends on
/opt/local/lib/libQt<whatever>.dylib
This is not a problem with gnuplot since gnuplot has to be built from
source. But it might be a problem for other packages. I'm not sure how
serious problem that is though. I don't expect many people would
really want to use "+framework" flag anyway. I used it out of pure
curiosity, and even then it's painful. With default setting upgrading
to new revision takes a fraction of a minute. With +framework upgrade
takes hours and hours and hours. I would not worry about this unless
bug reports start flying in.

The second reason why I wrote it was the response to this thought:

> This is just a bad idea: your package will install differently based on what's available, and not even consistently (e.g. archives).

(I was thinking of choosing the port variant based on whether
wxWidgets or wxWidgets-devel is already present. This would actually
not break archives. But currently "qt4-mac +framework" does.)

It's not really a serious issue, however it might be worth keeping it in mind.

Mojca