Function resolve_container_engine

e2e/rust/src/harness/container.rs:340–373

(
    legacy_selector: Option<&str>,
    explicit_engine: Option<&str>,
    e2e_driver: Option<&str>,
    probe: &impl ContainerEngineProbe,
)

}

fn resolve_container_engine(
    legacy_selector: Option<&str>,
    explicit_engine: Option<&str>,
    e2e_driver: Option<&str>,
    probe: &impl ContainerEngineProbe,
) -> Result<ResolvedContainerEngine, String> {
    if normalized_env(legacy_selector).is_some() {
        return Err(
            "OPENSHELL_E2E_CONTAINER_ENGINE is no longer supported; set CONTAINER_ENGINE=docker|podman instead"
                .to_string(),
        );
    }

    let explicit_engine = normalized_env(explicit_engine)
        .map(|value| validate_container_engine("CONTAINER_ENGINE", value))
        .transpose()?;
    let required_engine = required_engine_from_driver(e2e_driver);

    if let (Some(explicit), Some(required)) = (&explicit_engine, &required_engine)
        && explicit != required
    {
        return Err(format!(
            "CONTAINER_ENGINE={explicit} conflicts with OPENSHELL_E2E_DRIVER={required}; use CONTAINER_ENGINE={required} or unset CONTAINER_ENGINE"
        ));
    }

    if let Some(engine) = explicit_engine {
        require_engine_available(&engine, probe)
    } else if let Some(engine) = required_engine {
        require_engine_available(&engine, probe)
    } else {
        auto_detect_container_engine(probe)
    }
}

impl Drop for ContainerHttpServer {
    fn drop(&mut self) {