On 13 October 2015 at 06:23, Nathaniel Smith <[email protected]> wrote: > On Oct 12, 2015 10:16 AM, "Robert Collins" <[email protected]> > wrote: ... >> So until we solve the problems related to unloading something loaded >> into Python and loading a different version in and all the related >> pain that can occur - I think using Python function calls is a >> non-starter. > > I don't see the contradiction here. If you look at the original draft PEP > then it exactly specifies that builds get isolated environments, and build > tools are supposed to spawn a child and then have that child do a function > call using whatever mechanism they prefer.
Ok, so here's a worked example to let us debug the disconnect. Given: [email protected]: setup-requires: S~=1.0 install-requires: B [email protected]: setup-requires: S~=2.0 [email protected]: no dependencies at all. [email protected]: no dependencies at all. and no binaries of A or B... then: pip install A will do the following (key bits related to this proposal only, happy path only): - download the [email protected] sdist - read pypa.yaml and read the setup-requires + build-tool keys - download [email protected] and prepare a built version of it - place [email protected] into PYTHONPATH and the built versions bin into PATH - run the build-tool command to determine how to use it - run the resulting wheel-build command to build a wheel for [email protected] - read the wheel metadata in to determine A's install-requires - download the [email protected] sdist - read pypa.yaml and read the setup-requires + build-tool keys - download [email protected] and prepare a built version of it - place [email protected] into PYTHONPATH and the built versions bin into PATH - run the build-tool command to determine how to use it - run the resulting wheel-build command to build a wheel for [email protected] - read the wheel metadata in to determine B's install-requires - install the B wheel into the target environment - install the A wheel into the target environment Note the two places where PYTHONPATH and PATH need to be something other than the environment of pip itself. pip may not be installed in the target environment (or may be a different version than the pip installed there). I don't understand how you propose to have [email protected] and [email protected] co-exist in pip's Python process. -Rob -- Robert Collins <[email protected]> Distinguished Technologist HP Converged Cloud _______________________________________________ Distutils-SIG maillist - [email protected] https://mail.python.org/mailman/listinfo/distutils-sig
