Port xapian-bindings' dependency on MacPorts' (outdated) ruby port

[René J.V. Bertin]

On Thursday April 16 2015 08:54:30 Chris Jones wrote:

>If the port needs ruby it should depend on a macports ruby version and 
>not rely on the system one, regardless of what version the system one 
>is. This is normal macports behavior, to provide a standard version 
>across all OSX versions.

It also leads to a profusion of additional ports and dependencies to maintain, and periodic update nightmares just because the default python/perl/ruby version has been updated. This is all the more annoying if we're talking about a build dependency on python/perl/ruby.
What would be the implications of providing (say) variants that leverage the system python/perl/ruby, other than the obvious loss of binary packages?
Have there been known instances of a major python/perl/ruby version update in an OS update (as opposed to upgrade)?

R.