#!/usr/bin/env python3
"""Check only mro_implementation's to_merge declaration and allocation 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: PyObject **to_merge; must be in the opening declaration block"
assert len(re.findall(r"\bPyObject\s*\*\*\s*to_merge\b", body)) == 1, (
    "mro_implementation: declare to_merge exactly once"
)
assert len(re.findall(r"\bto_merge\s*=(?!=)", body)) == 1, (
    "mro_implementation: assign to_merge exactly once"
)
expected = """
    if (check_duplicates(bases) < 0) {
        return NULL;
    }
    to_merge = PyMem_New(PyObject *, n + 1);
    if (to_merge == NULL) {
        PyErr_NoMemory();
        return NULL;
    }
"""
allocation = re.split(
    r"\bfor\s*\(", body[body.index("if (check_duplicates(bases)"):], maxsplit=1
)[0]
assert allocation.split() == expected.split(), (
    "mro_implementation: preserve allocation after duplicate validation and error handling"
)
print("mro_implementation to_merge C89 declaration and unchanged allocation timing: PASS")