[MacPorts] #59303: scons: switch to python3x (was: Scons should not require python2)

[MacPorts]

#59303: scons: switch to python3x
--------------------------+------------------------
  Reporter:  llamafilm    |      Owner:  ryandesign
      Type:  enhancement  |     Status:  assigned
  Priority:  Normal       |  Milestone:
 Component:  ports        |    Version:  2.6.1
Resolution:               |   Keywords:
      Port:  scons        |
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Changes (by ryandesign):

 * owner:  (none) => ryandesign
 * status:  new => assigned
 * type:  defect => enhancement


Comment:

 It is reasonable to investigate switching the scons port to use python37.
 However, I am concerned that doing so might cause problems for some of the
 ports that use scons. They might use python2-specific features in their
 SConscript files and might break if we switch to python3. (Arguably, those
 would be bugs in those other ports, which should be fixed.) Or they might
 use other python modules in their SConscript files; if they do, the port
 would declare dependencies on the python27 versions of those modules, and
 if we change the python version that scons uses, we would have to identify
 all those ports and update their dependencies to use the new python
 version. So while it could be done, it should be done carefully.

 One concern that occurs to me is mongodb, which is a large software
 package that uses scons as its build system. At least in version 4.0.x,
 its build scripts specifically test for python 2.7 and exit with an error
 if any other version is used. I have not checked [ticket:58921 mongodb
 4.2.0], and I have not tested whether using python3 would break this
 build, but I would not want to make a change to the scons port that would
 break mongodb, or other ports. As far as I know, at present, everything is
 working fine with python27, and while I understand that support for
 python27 will end soon and ideally we should move to a newer version, I am
 more interested in not breaking things.

 I am the maintainer of the scons port so I will assign the ticket to
 myself but I am unprepared to invest the necessary time in doing any of
 this work or investigation at this time. If others wish to do so and
 submit a pull request of a working tested solution, that's fine.

-- 
Ticket URL: <https://trac.macports.org/ticket/59303#comment:1>
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