fn ensure_gil_enabled()

in include/pyo3/pyo3-ffi/build.rs [124:145]

• 21 lines of code
• 7 McCabe index (conditional complexity)

fn ensure_gil_enabled(interpreter_config: &InterpreterConfig) -> Result<()> {
    let gil_enabled = interpreter_config
        .build_flags
        .0
        .contains(&BuildFlag::Py_GIL_DISABLED)
        .not();
    ensure!(
        gil_enabled || std::env::var("UNSAFE_PYO3_BUILD_FREE_THREADED").map_or(false, |os_str| os_str == "1"),
        "the Python interpreter was built with the GIL disabled, which is not yet supported by PyO3\n\
        = help: see https://github.com/PyO3/pyo3/issues/4265 for more information\n\
        = help: please check if an updated version of PyO3 is available. Current version: {}\n\
        = help: set UNSAFE_PYO3_BUILD_FREE_THREADED=1 to suppress this check and build anyway for free-threaded Python",
        std::env::var("CARGO_PKG_VERSION").unwrap()
    );
    if !gil_enabled && interpreter_config.abi3 {
        warn!(
            "The free-threaded build of CPython does not yet support abi3 so the build artifacts will be version-specific."
        )
    }

    Ok(())
}