#!/usr/bin/env python3
"""Check the mro_entries declaration and preserve base lookup ordering."""
import re
from pathlib import Path

source = Path("cpython/Objects/typeobject.c").read_text()
match = re.search(
    r"\nstatic int\ntype_new_get_bases\(type_new_ctx \*ctx, PyObject \*\*type\)\n\{(.*?)\n\}",
    source, re.S,
)
assert match, "type_new_get_bases definition missing"
body = re.sub(r"/\*.*?\*/|//[^\n]*", "", match.group(1), flags=re.S)
assert re.search(
    r"for \(i = 0; i < nbases; i\+\+\) \{\s*"
    r"PyObject \*base = PyTuple_GET_ITEM\(ctx->bases, i\);\s*"
    r"PyObject \*mro_entries;\s*if \(PyType_Check\(base\)\)",
    body,
), "type_new_get_bases: mro_entries must precede loop statements (C89)"
assert len(re.findall(r"\bPyObject\s*\*\s*mro_entries\b", body)) == 1, (
    "declare mro_entries exactly once"
)
loop = body[body.index("    for ("):body.index("    winner = _PyType_CalculateMetaclass(")]
expected = """
    for (i = 0; i < nbases; i++) {
        PyObject *base = PyTuple_GET_ITEM(ctx->bases, i);
        PyObject *mro_entries;
        if (PyType_Check(base)) {
            continue;
        }
        if (_PyObject_LookupAttr(base, &_Py_ID(__mro_entries__),
                                 &mro_entries) < 0) {
            return -1;
        }
        if (mro_entries != NULL) {
            PyErr_SetString(PyExc_TypeError,
                            "type() doesn't support MRO entry resolution; "
                            "use types.new_class()");
            Py_DECREF(mro_entries);
            return -1;
        }
    }
"""
assert loop.split() == expected.split(), (
    "preserve base lookup, type skip, attribute lookup, error handling, and decref order"
)
print("type_new_get_bases mro_entries C89 declaration and lookup ordering: PASS")