#!/usr/bin/env python3
"""Check type_set_bases's new_base declaration and best_base call timing."""
import re
from pathlib import Path

source = Path("cpython/Objects/typeobject.c").read_text()
match = re.search(
    r"\nstatic int\ntype_set_bases\(PyTypeObject \*type, PyObject \*new_bases, void \*context\)\n\{(.*?)\n\}",
    source,
    re.S,
)
assert match, "type_set_bases definition missing"
body = re.sub(r"/\*.*?\*/|//[^\n]*", "", match.group(1), flags=re.S)
assert re.match(
    r"\s*Py_ssize_t n;\s*Py_ssize_t i;\s*PyTypeObject \*new_base;\s*PyObject \*old_bases;\s*PyTypeObject \*old_base;\s*PyObject \*temp;\s*int res;\s*if\b",
    body,
), "type_set_bases: new_base must be in the opening declaration block"
assert len(re.findall(r"\bPyTypeObject\s*\*\s*new_base\b", body)) == 1, (
    "type_set_bases: declare new_base exactly once"
)
assert len(re.findall(r"\bnew_base\s*=(?!=)", body)) == 1, (
    "type_set_bases: assign new_base exactly once"
)
assert len(re.findall(r"\bbest_base\s*\(", body)) == 1, (
    "type_set_bases: call best_base exactly once"
)
expected = """
        if (PyType_IsSubtype(base, type) ||
            (base->tp_mro != NULL && type_is_subtype_base_chain(base, type)))
        {
            PyErr_SetString(PyExc_TypeError,
                            "a __bases__ item causes an inheritance cycle");
            return -1;
        }
    }

    new_base = best_base(new_bases);
    if (new_base == NULL)
        return -1;

    if (!compatible_for_assignment(type->tp_base, new_base, "__bases__")) {
        return -1;
    }

    old_bases = type->tp_bases;
"""
assert " ".join(expected.split()) in " ".join(body.split()), (
    "type_set_bases: preserve best_base assignment after the validation loop, "
    "followed by the NULL guard and compatibility check before saving old bases"
)
print("type_set_bases new_base C89 declaration and unchanged evaluation order: PASS")