[petsc-dev] Configure won't find python

[Jed Brown]

Satish Balay <balay at mcs.anl.gov> writes:

> On Sat, 18 Apr 2020, Jed Brown wrote:
>
>> This indicates that /usr/bin/python will not exist in the next release.
>> 
>> https://wiki.debian.org/Python/2Removal
>> 
>> I don't know what exactly that means.  I'd guess it means one will need
>> to use backports to get python2 if one really needs it; even so, I don't
>> know if /usr/bin/python will exist.  Perhaps only /usr/bin/python2.
>> 
>> 
>> I don't know if they'll reintroduce /usr/bin/python at some release well
>> in the future, but we should expect for it to not exist for a while.
>> 
>
> The above URL is about packaging guidelines. i.e the packages in the distro should correctly use python2 or python3 dependencies.
>
> I don't see a mention of /usr/bin/python will be. [so yes - so we don't know what it will be - when python3 becomes the default]

>From the page:

  make sure package doesn't call python at build- or compile time (as there won't be a python package and no python command in bullseye, only python3.)

> But until then - I don't consider missing /usr/bin/python a transition. jedbrown/mpich-ccache would be an example of user willfully not installing the default system python. (similar to not installing system default compilers). So don't think its a case of configure bug of not handling proper installs. [sure we have work-around for buggy compilers and some buggy installs so any support for missing /usr/bin/python  would be on that side].
>
> I wonder what python folk recommendation here is wrt dual use scripts..
>
> Satish