[MacPorts] #57767: py36-graph-tool uses incorrect python version 2.7

[MacPorts]

#57767: py36-graph-tool uses incorrect python version 2.7
----------------------------------+----------------------
  Reporter:  ssllmit              |      Owner:  count0
      Type:  defect               |     Status:  assigned
  Priority:  Normal               |  Milestone:
 Component:  ports                |    Version:  2.5.4
Resolution:                       |   Keywords:
      Port:  py-graph-tool boost  |
----------------------------------+----------------------

Comment (by ssllmit):

 I tried the suggestion of adding {{{+python37}}} to
 {{{/opt/local/etc/macports/variants.conf}}}, but this causes breakage of
 many ports.

 I encountered this issue while doing automated migration of a Macports
 setup (https://trac.macports.org/wiki/Migration), and while doing an
 automated update to python37:

 {{{
 sudo port -pN install python37 `port -qv installed | egrep -e '^\s*py36' |
 perl -ane 'chomp; $_ = $F[0]; s/py36/py37/; print $_, " ";'`
 }}}

 With the current port file settings, this process will break because ports
 like {{{boost}}} aren't installed with the correct python version.

-- 
Ticket URL: <https://trac.macports.org/ticket/57767#comment:8>
MacPorts <https://www.macports.org/>
Ports system for macOS