Function warn_explicit

crates/vm/src/warn.rs:335–453

(
    category: Option<PyTypeRef>,
    message: PyObjectRef,
    filename: PyStrRef,
    lineno: usize,
    module: Option<PyObjectRef>,
    registry: PyObjectRef,
    source_line: Option<PyObjectRef>

/// Core warning logic matching `warn_explicit()` in `_warnings.c`.
#[allow(clippy::too_many_arguments)]
pub(crate) fn warn_explicit(
    category: Option<PyTypeRef>,
    message: PyObjectRef,
    filename: PyStrRef,
    lineno: usize,
    module: Option<PyObjectRef>,
    registry: PyObjectRef,
    source_line: Option<PyObjectRef>,
    source: Option<PyObjectRef>,
    vm: &VirtualMachine,
) -> PyResult<()> {
    // Normalize module. None → silent return (late-shutdown safety).
    let module = module.unwrap_or_else(|| normalize_module(&filename, vm));
    if vm.is_none(&module) {
        return Ok(());
    }

    // Normalize message.
    let is_warning = message.fast_isinstance(vm.ctx.exceptions.warning);
    let (text, category, message) = if is_warning {
        let text = message.str(vm)?;
        let cat = message.class().to_owned();
        (text, cat, message)
    } else {
        // For non-Warning messages, convert to string via str()
        let text = message.str(vm)?;
        let cat = category.unwrap_or_else(|| vm.ctx.exceptions.user_warning.to_owned());
        let instance = cat.as_object().call((text.clone(),), vm)?;
        (text, cat, instance)
    };

    let lineno_obj: PyObjectRef = vm.ctx.new_int(lineno).into();

    // key = (text, category, lineno)
    let key: PyObjectRef = PyTuple::new_ref(
        vec![
            text.clone().into(),
            category.as_object().to_owned(),
            lineno_obj.clone(),
        ],
        &vm.ctx,
    )
    .into();

    // Check if already warned
    if !vm.is_none(&registry) && already_warned(&registry, key.clone(), false, vm)? {
        return Ok(());
    }

    // Get filter action
    let action = get_filter(
        category.as_object().to_owned(),
        text.clone().into(),
        lineno,
        module,
        vm,
    )?;
    let action_str = PyStrRef::try_from_object(vm, action)