Support overriding version from environment

[mweinelt]

We at nixpkgs package python projects from GitHub by pulling their tarball, which is much quicker than doing a full or bare git checkout. Subsequently, we don't have a Git repo that setuptools-git-versioning could infer the version from.

With setuptools-scm there is an environment variable SETUPTOOLS_SCM_PRETEND_VERSION through which the version can be explicitly. Adding support for such an escape hatch would be appreciated.

[dolfinus]

Hi.

Could the repo maintainer create version_file? It can be used when tags are missing.

[dolfinus]

I've added recommendation to use version_file as default schema, mentioning this issue:

• https://setuptools-git-versioning.readthedocs.io/en/stable/schemas/tag/index.html
• https://setuptools-git-versioning.readthedocs.io/en/stable/schemas/file/index.html

[mweinelt]

Thanks, I apparently forgot to check back in.