New Build System Status

[Joel Sherrill]

On Mon, Nov 25, 2019 at 3:19 PM Chris Johns <chrisj at rtems.org> wrote:

> On 26/11/19 8:05 am, Joel Sherrill wrote:
> > On Mon, Nov 25, 2019 at 2:12 AM Sebastian Huber
> > <sebastian.huber at embedded-brains.de <mailto:
> sebastian.huber at embedded-brains.de>>
> > wrote:
> >
> >     On 25/11/2019 08:55, Chris Johns wrote:
> >     >
> >     > On 25/11/19 5:28 pm, Sebastian Huber wrote:
> >     >>
> >     >> On 24/11/2019 23:25, Chris Johns wrote:
> >     >>>>> Should there be a note or something about waf needing python
> and we
> >     recommend
> >     >>>>> python3? Plus waf needs a `python` installed and not just
> `python2` or
> >     >>>>> `python3`?
> >     >>>> I think this belongs to the Host Computer section. The quick
> start uses the
> >     >>>> RSB, so if you managed to build the tools, you must have a
> working Python.
> >     >>>> The RSB uses Python and the RTEMS Tools use waf.
> >     >>> The RSB can use python2 or python3 without a python. What about
> a note
> >     to say
> >     >>> ... "Waf uses python and you need to make this command available
> on your
> >     system".
> >     >> Now I am a bit confused. I thought every UNIX-like system
> provides a
> >     >>
> >     >> #!/usr/bin/env python
> >     >>
> >     >> which maps to Python 2 or 3?
> >     >>
> >     > Apparently on some distros the python executable is not
> automatically
> >     installed
> >     > with a suitable python2 or python3. I am not aware of the
> specifics of
> >     this but
> >     > it was raised as an issue that I fixed in the RSB:
> >     >
> >     > https://devel.rtems.org/ticket/3537
> >
> >     I have never seen a system in which
> >
> >     #!/usr/bin/env python2
> >
> >     or
> >
> >     #!/usr/bin/env python3
> >
> >     works, but not
> >
> >     #!/usr/bin/env python
>
> I agree however this is the post from Joel about a class he held ...
>
> https://lists.rtems.org/pipermail/devel/2018-October/023150.html
>
> and I posted the change here ...
>
> https://lists.rtems.org/pipermail/devel/2018-October/023296.html
>
> >     How many Python scripts would stop to work in this case? However, the
> >     availability of a python command is not mandatory according to:
> >
> >     https://www.python.org/dev/peps/pep-0394/
>
> I am aware of this and I support it however Linux distros seems to feel
> there
> are cases for exceptions, we have this one and there is also pax.
>
> The pax and this python case are similar, do we say "We are correct, fix
> your
> host or raise a bug on your distro" or do we attempt to smooth over the
> cracks
> and attempt to just work?
>
> In the case of ubuntu, maybe someone with some experience with it can see
> what
> is needed and update the documentation?
>
> >     I think we should note in the "Host Computer" section that a "python"
> >     command is mandatory for RTEMS and remove the RSB extra stuff.
>
> The argument was presented to me that the RSB should just work even in
> this case
> and so that is what I did. I am fine to remove that support, it is an
> average hack.
>
> > Chris can answer to that.
>
> Done.
>
> > But on Centos 7, we have:
> >
> > $ type python
> > python is /usr/bin/python
> > $ python --version
> > Python 2.7.5
> > $ type python2
> > python2 is /usr/bin/python2
> > $ type python3
> > bash: type: python3: not found
> > $ env python
> > Python 2.7.5 (default, Aug  7 2019, 00:51:29)
> > [GCC 4.8.5 20150623 (Red Hat 4.8.5-39)] on linux2
> > Type "help", "copyright", "credits" or "license" for more information.
> >>>>
> >
> > and if I activate the SCL for Python 3:
> >
> > $ scl enable rh-python36 bash
>
> >
>
> > [joel at localhost rtems-work]$ type python
>
> >
>
> > python is /opt/rh/rh-python36/root/usr/bin/python
>
> >
>
> > [joel at localhost rtems-work]$ python --version
>
> >
>
> > Python 3.6.3
>
> And on ubuntu? The original post was about that distro.
>

 Welcome to Ubuntu 18.04.3 LTS (GNU/Linux 4.15.0-66-generic x86_64)

....
$ type python
python is /usr/bin/python
$ python --version
Python 2.7.15+
$ env python
Python 2.7.15+ (default, Oct  7 2019, 17:39:04)
[GCC 7.4.0] on linux2
Type "help", "copyright", "credits" or "license" for more information.
>>>
$ python2
Python 2.7.15+ (default, Oct  7 2019, 17:39:04)
[GCC 7.4.0] on linux2
Type "help", "copyright", "credits" or "license" for more information.
>>>
$ python3
Python 3.6.8 (default, Oct  7 2019, 12:59:55)
[GCC 8.3.0] on linux
Type "help", "copyright", "credits" or "license" for more information.
>>>


>
> Chris
>
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