Python PortGroup resets depends_lib ?

[René J.V. Bertin]

Hi,

Is it "normal" that the Python PortGroup resets `depends_lib` in the code called through

python.versions X Y [Z]

?

This may work fine for pure Python ports, but it introduces annoying side-effects with the dependencies that may have been set by other PortGroups (cf. port:py-pyqt4).
It turns out to be perfectly possible to cache and restore the settings, e.g.

PortGroup qt4 1.0
set depends_lib_backup ${depends_lib}
PortGroup python 1.0

# ...
python.versions 27 34

depends_lib-append ${depends_lib_backup}

Why does the PortGroup not do this, or have I missed a trick to achieve the same thing?

R.