feat(package): Extract package version from PEP 621 compliant pyproject.toml

[FollowTheProcess]

Description

This PR adds a function to the package module to extract the package version from a PEP 621 compliant pyproject.toml

Motivation and Context

Closes #3949

Screenshots (if appropriate):

How Has This Been Tested?

• I have tested using MacOS
• I have tested using Linux
• I have tested using Windows

Ran cargo test, cargo clippy --all-targets --all-features and cargo fmt

Checklist:

• I have updated the documentation accordingly.
• I have updated the tests accordingly.

[FollowTheProcess]

I'm afraid my noob level rust is showing, I've tried a few different variations on the following but can't seem to get it to work:

fn get_pyproject_version(context: &Context, config: &PackageConfig) -> Option<String> {
    let file_contents = context.read_file_from_pwd("pyproject.toml")?;
    let pyproject_toml: toml::Value = toml::from_str(&file_contents).ok()?;

    if let Some(poetry_version) = pyproject_toml
        .get("tool")?
        .get("poetry")?
        .get("version")?
        .as_str()
    {
        format_version(poetry_version, config.version_format);
    }

    if let Some(pep621_version) = pyproject_toml.get("project")?.get("version")?.as_str() {
        format_version(pep621_version, config.version_format);
    }

    None
}

I get the following test failures:

So both a poetry pyproject.toml and a pep621 pyproject.toml are returning None and I can't see why. In my head the code above should check if there's a:

[tool.poetry]
version = "0.1.0"

If so, grabbing the version and formatting it.

If not, check for a:

[project]
version = "0.1.0"

If so, grabbing the version and formatting it. And if version is a table here, the .as_str() should return None according to the docs.

And finally if we get here and haven't found anything, return a None anyway.

Obviously my understanding is wrong otherwise I wouldn't be here! Can anyone help me out? 🙂

[davidkna]

When encountering None ? will return None from the function and stop proceeding. You can either write two additional functions for both approaches to ensure the function ? does not stop execution (get_poetry_version(&pyproject_toml).or_else(|| get_pep612_version(&pyproject_toml))) or you could handle the None-values without returning, for instance with and_then.

pyproject_toml
        .get("tool")
        .and_then(|tool| tool.get("poetry"))
        .and_then(|poetry| poetry.get("version"))
        .and_then(|version| version.as_str())

[FollowTheProcess]

@davidkna Worked perfectly! Thanks for the help

[FollowTheProcess]

The way I've written this atm is it will prioritise a PEP 621 pyproject.toml so in the weird case where someone has both a [project] and a [tool.poetry], it will show the version from the [project] table and ignore the [tool.poetry] which I think is sensible behaviour as PEP 621 is the formal standard and is currently supported in a number of python build backends.

Poetry is the odd one out here and if/when it eventually adopts PEP 621, poetry pyproject.toml files will replace [tool.poetry] with [project] anyway.

[andytom]

Thank you for your contribution @FollowTheProcess and thanks for reviewing @davidkna.