PyO3/pyo3 · error

unsupported Python interpreter

Error message

unsupported Python interpreter

What it means

Sentinel error from PythonImplementation::from_soabi: the SOABI string read from sysconfigdata did not start with any recognized prefix (cpython/pypy/graalpy), so the interpreter implementation could not be identified. The faulty input is the SOABI value itself — empty, mangled, or from an unsupported runtime.

Source

Thrown at pyo3-build-config/src/impl_.rs:1494

    PyPy,
    GraalPy,
    RustPython,
}

impl PythonImplementation {
    fn is_pypy(self) -> bool {
        self == PythonImplementation::PyPy
    }

    fn from_soabi(soabi: &str) -> Result<Self> {
        if soabi.starts_with("pypy") {
            Ok(PythonImplementation::PyPy)
        } else if soabi.starts_with("cpython") {
            Ok(PythonImplementation::CPython)
        } else if soabi.starts_with("graalpy") {
            Ok(PythonImplementation::GraalPy)
        } else {
            bail!("unsupported Python interpreter");
        }
    }
}

impl Display for PythonImplementation {
    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
        match self {
            PythonImplementation::CPython => write!(f, "CPython"),
            PythonImplementation::PyPy => write!(f, "PyPy"),
            PythonImplementation::GraalPy => write!(f, "GraalVM"),
            PythonImplementation::RustPython => write!(f, "RustPython"),
        }
    }
}

impl FromStr for PythonImplementation {
    type Err = Error;
    fn from_str(s: &str) -> Result<Self> {

View on GitHub (pinned to ac9b6899d3)

Solutions

1. Check the SOABI entry in the _sysconfigdata file for corruption or truncation
2. Use a CPython, PyPy, or GraalPy target whose SOABI starts with a known prefix
3. Set PYO3_CROSS_PYTHON_IMPLEMENTATION explicitly so the build does not have to infer it from SOABI

When it happens

Trigger: Thrown at pyo3-build-config/src/impl_.rs:1494 when the library encounters an invalid state.

Common situations: See trigger scenarios.

AI-assisted analysis of PyO3/pyo3@ac9b6899d3 (2026-09-05). Data as JSON: /api/errors/a851aeed333ae598. Report an issue: GitHub.