#!/usr/bin/env python3
"""Check type_set_bases's base declaration and post-validation cast 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)
loop = body.split("for (i = 0; i < n; i++) {", 1)[1].split(
    "new_base = best_base(new_bases);", 1
)[0]
assert re.match(
    r"\s*PyObject \*ob = PyTuple_GET_ITEM\(new_bases, i\);\s*PyTypeObject \*base;\s*if\b",
    loop,
), "type_set_bases: base must be in the loop's opening declaration block"
assert len(re.findall(r"\bPyTypeObject\s*\*\s*base\b", body)) == 1, "declare base exactly once"
assert len(re.findall(r"\bbase\s*=(?!=)", body)) == 1, "assign base exactly once"
expected = """
        PyObject *ob = PyTuple_GET_ITEM(new_bases, i);
        PyTypeObject *base;
        if (!PyType_Check(ob)) {
            PyErr_Format(PyExc_TypeError,
                         "%s.__bases__ must be tuple of classes, not '%s'",
                         type->tp_name, Py_TYPE(ob)->tp_name);
            return -1;
        }
        base = (PyTypeObject*)ob;

        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;
        }
    }
"""
assert loop.split() == expected.split(), (
    "type_set_bases: preserve item retrieval, validation, post-validation base "
    "assignment, and inheritance-cycle checks in their original order"
)
print("type_set_bases base C89 declaration and unchanged evaluation order: PASS")