Old setuptools_scm issue (FreeBSD, for example)

[henryiii]

Describe the bug

Pipx expects setuptools_scm (via hatch_vcs) to produce __version__ in the default template. However, older versions, such as the one supplied in FreeBSD, do not (this alias was added in version 7; for other reasons, FreeBSD is stuck on 6 and treats 7 as a new package).

https://github.com/pypa/pipx/blob/6918c4de5898d65807a2255eed43b6f5a6cf1a21/src/pipx/main.py#L31C1-L32C1

Two easy fixes and one less so: the one I usually do is to import version (the original name) as __version__ (like in https://github.com/scikit-build/scikit-build-core/blob/f8c5798897852e107df0683893de59e15c558baf/src/scikit_build_core/__init__.py#L9). That was the original name, and is always available. You can also specify the template, which allows you to put whatever you want in version.py, but does require a bit more configuration. And the less-ideal fix would be to limit the version of setuptools_scm that hatch_vcs pulls in to some minimum that includes the addition of this feature (v7).

How to reproduce

Seen in abravalheri/validate-pyproject#142, logs: https://github.com/abravalheri/validate-pyproject/pull/142/checks?check_run_id=20500888256

pipx run coverage xml -o coverage.xml
Traceback (most recent call last):
  File "/usr/local/bin/pipx", line 5, in <module>
    from pipx.main import cli
  File "/usr/local/lib/python3.9/site-packages/pipx/main.py", line 31, in <module>
    from pipx.version import __version__
ImportError: cannot import name '__version__' from 'pipx.version' (/usr/local/lib/python3.9/site-packages/pipx/version.py)

Expected behavior

Would be nice not to have pipx crash on FreeBSD.

[henryiii]

Currently FreeBSD is planning to patch Pipx to add a template: https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=275946