python setup.py sdist only works with pyproject.toml when package is pre-installed in venv

[jamesbraza]

I am hitting what seems to be an edge when combining python setup.py sdist, setup.py, and pyproject.toml.

Here is my pyproject.toml:

[build-system]

requires = ["setuptools", "wheel", "setuptools_scm[toml]"]


[tool.setuptools_scm]

write_to = "desired/path/to/__version__.py"
root = ".."
relative_to = '__file__'

And my venv at the beginning:

Python==3.7.9
pip==20.2.4
setuptools==47.1.0
setuptools-scm==4.1.2

---

Case 1: didn't pre-install package

python setup.py sdist

Result: version of 0.0.0 (didn't work)

#386 seems related.

Case 2: pre-installed package

pip install -e .
python setup.py sdist

Result: version of pkg-name-0.1.1.dev10+g28f91ce (works)

Case 3: didn't install package + added config directly to setup.py

I add the pyproject.toml config section to setup.py's setup function:

setup(
    use_scm_version={
        "write_to": "desired/path/to/__version__.py",
        "root": "..",
        "relative_to": __file__,
    },
)

And do not have to pre-install the package:

python setup.py sdist

Result: version of pkg-name-0.1.1.dev10+g28f91ce.d20201030 (works)

Note: this version has the date appended for some reason

---

The Issue

I would like to be able to use Case 1 above. Unfortunately, it doesn't seem to work. What might be the problem? I have tried combing through the docs several times over, and haven't found any solutions.

In the meantime, I will be going with Case 2.

[RonnyPfannschmidt]

The sdist command of setuptools is unaware of pep 517/8,so preinstall is a required step

[jamesbraza]

Well, that makes sense! Thank you @RonnyPfannschmidt !

[RonnyPfannschmidt]

As extra tool add imports to setup.py

That way people cannot run it without installing setuptools_scm and toml