Re: [dpdk-dev] [PATCH 0/9] python2 deprecation notice

[Bruce Richardson <bruce.richardson@intel.com>]

On Fri, Jul 10, 2020 at 03:33:58PM +0200, Robin Jarry wrote:
> Hi Louise,
> 
> 2020-07-10, Louise Kilheeney:
> > This patchset adds deprecation notices to python scripts,
> > warning of the removal of python2 support from the DPDK 20.11 release.
> 
> While showing warnings to users about Python 2 support drop in 20.11 is
> good, it seems like the shebangs in a lot of these scripts still refer
> to "python".
> 
> dpdk$ git describe 
> v20.05-623-geff30b59cc2e
> dpdk$ git grep '#.*!.*python\>'
> app/test-bbdev/test-bbdev.py:1:#!/usr/bin/env python
> app/test-cmdline/cmdline_test.py:1:#!/usr/bin/env python
> app/test/autotest.py:1:#!/usr/bin/env python
> buildtools/map_to_win.py:1:#!/usr/bin/env python
> config/arm/armv8_machine.py:1:#!/usr/bin/python
> devtools/update_version_map_abi.py:1:#!/usr/bin/env python
> usertools/cpu_layout.py:1:#!/usr/bin/env python
> usertools/dpdk-devbind.py:1:#! /usr/bin/env python
> usertools/dpdk-pmdinfo.py:1:#!/usr/bin/env python
> usertools/dpdk-telemetry-client.py:1:#! /usr/bin/env python
> 
> On many distros, "python" still points (as of today) to python2. You
> series will cause warnings that cannot be avoided.
> 
> Also, on some distros, "python" does not exist at all (RHEL 8 and CentOS
> 8 for example). And only "python2" or "python3" are available.
> 
> I wonder if it would not be better to find a way to make these shebangs
> "dynamic" somehow. It is not trivial and I don't see any other solution
> than plain modification of the shebangs at build time.
> 
> However, there is no way (to my knowledge) to specify which version of
> python is "selected" during the build.
> 
> Does anyone have a proper solution?
>

In the absense of a "proper" solution, is the simplest option to change the
shebangs to all be python3, but leave the python2 compatibility in place,
and add the warnings for anyone running it explicitly using python2?