bpo-32030: Move PYTHONPATH to _PyMainInterpreterConfig

[vstinner]

Move _PyCoreConfig.module_search_path_env to _PyMainInterpreterConfig
structure.

https://bugs.python.org/issue32030

[ncoghlan]

Thanks! And this means at some point in the future we'll hopefully be able to replace the wchar_t * with a PyList * as PEP 432 describes :)

[vstinner]

Thanks! And this means at some point in the future we'll hopefully be able to replace the wchar_t * with a PyList * as PEP 432 describes :)

I'm not happy with the wchar_t* type neither, but please let me move step by step. Just the commit d434110 si already huge, whereas technically, it does almost nothing :-) While the PEP 432 is nice to read, it's not the case for the huge pile of legacy C code in CPython :-)

Moreover, I always fear the risk of regression, so I really prefer to make baby steps, and triple checks each commit, to make sure that we don't break anymore :-)

[ncoghlan]

Aye, my comment was intended as praise for your strategy, not criticism. Consolidating the settings using their existing C level data types first, and only then looking at switching from C types to Python types makes a lot of sense :)