conda-forge build fails because of too long file name

[ltalirz]

See https://circleci.com/gh/conda-forge/reentry-feedstock/14?utm_campaign=vcs-integration-link&utm_medium=referral&utm_source=github-build-link

The issue occurs here:
https://github.com/DropD/reentry/blob/f1cd3bfc0a9af5d2c31fa7a79b9a4208c3ddc019/reentry/config.py#L73

Error message:

py.error.ENAMETOOLONG: [File name too long]: open('/home/conda/.config/reentry/data/home.conda.feedstock_root.build_artifacts.reentry_1527279672474._test_env_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_placehold_.bin.python', 'w')

Once could argue this is more a problem of conda-build than of reentry, still it would be nice to fix it.

[DropD]

The solution for this might be to use an md5 hash instead of a mangled path for the name.

[ltalirz]

jep... as long as this isn't fixed, reentry won't be on conda-forge.

[ltalirz]

from version 1.2.0 onwards, reentry cannot even be imported in the conda test environment anymore... and conda-forge requires at least some test.
I.e. we are truly stuck

[ltalirz]

Fixed in #37