#!/usr/bin/env python3
"""Check only mro_implementation's n declaration and evaluation timing."""
import re
from pathlib import Path

source = Path("cpython/Objects/typeobject.c").read_text()
match = re.search(
    r"\nstatic PyObject \*\nmro_implementation\(PyTypeObject \*type\)\n\{(.*?)\n\}",
    source,
    re.S,
)
assert match, "mro_implementation definition missing"
body = re.sub(r"/\*.*?\*/", "", match.group(1), flags=re.S)
assert re.match(
    r"\s*PyObject \*bases;\s*Py_ssize_t n;\s*Py_ssize_t i;"
    r"\s*PyObject \*\*to_merge;\s*PyObject \*result;\s*if\b",
    body,
), (
    "mro_implementation: Py_ssize_t n; must be in the opening declaration block"
)
assert len(re.findall(r"\bPy_ssize_t\s+n\b", body)) == 1, (
    "mro_implementation: declare n exactly once"
)
expected_prefix = """
    PyObject *bases;
    Py_ssize_t n;
    Py_ssize_t i;
    PyObject **to_merge;
    PyObject *result;
    if (!_PyType_IsReady(type)) {
        if (PyType_Ready(type) < 0)
            return NULL;
    }
    bases = type->tp_bases;
    n = PyTuple_GET_SIZE(bases);
    for (i = 0; i < n; i++) {
"""
assert body.split()[:len(expected_prefix.split())] == expected_prefix.split(), (
    "mro_implementation: preserve n evaluation timing and loop index initialization"
)
assert len(re.findall(r"\bn\s*=(?!=)", body)) == 1, (
    "mro_implementation: assign n exactly once"
)
print("mro_implementation n C89 declaration and unchanged evaluation order: PASS")