#!/usr/bin/env python3
"""Check only mro_hierarchy's new_mro declaration and guarded read timing."""
import re
from pathlib import Path

source = Path("cpython/Objects/typeobject.c").read_text()
match = re.search(
    r"\nstatic int\nmro_hierarchy\(PyTypeObject \*type, PyObject \*temp\)\n\{(.*?)\n\}",
    source,
    re.S,
)
assert match, "mro_hierarchy definition missing"
body = re.sub(r"/\*.*?\*/", "", match.group(1), flags=re.S)
assert re.match(r"\s*PyObject \*old_mro;\s*PyObject \*new_mro;", body), (
    "mro_hierarchy: PyObject *new_mro; must be in the opening declarations"
)
assert len(re.findall(r"\bPyObject\s*\*\s*new_mro\b", body)) == 1, (
    "mro_hierarchy: declare new_mro exactly once without initialization"
)
expected_prefix = """
    PyObject *old_mro;
    PyObject *new_mro;
    PyObject *tuple;
    Py_ssize_t n;
    Py_ssize_t i;
    int res = mro_internal(type, &old_mro);
    if (res <= 0) {
        return res;
    }
    new_mro = type->tp_mro;

    if (old_mro != NULL) {
        tuple = PyTuple_Pack(3, type, new_mro, old_mro);
    }
    else {
        tuple = PyTuple_Pack(2, type, new_mro);
    }
"""
assert body.split()[:len(expected_prefix.split())] == expected_prefix.split(), (
    "mro_hierarchy: preserve the guard, new_mro read timing, and tuple branches"
)
assert len(re.findall(r"\bnew_mro\s*=", body)) == 1, (
    "mro_hierarchy: assign new_mro exactly once"
)
print("mro_hierarchy new_mro C89 declaration and guarded read timing: PASS")