#!/usr/bin/env python3
"""Check only maybe_freelist_push's index declaration and evaluation order."""
import re
import sys
from pathlib import Path

source = Path(sys.argv[1] if len(sys.argv) > 1 else "cpython/Objects/tupleobject.c")
match = re.search(
    r"static inline int\nmaybe_freelist_push\(PyTupleObject \*op\)\n\{(.*?)\n\}",
    source.read_text(),
    re.S,
)
assert match, "maybe_freelist_push definition missing"
body = match.group(1)
assert re.match(
    r"\s*#if PyTuple_NFREELISTS > 0\s*"
    r"PyInterpreterState \*interp = _PyInterpreterState_GET\(\);\s*"
    r"Py_ssize_t index;\s*#ifdef Py_DEBUG",
    body,
), "maybe_freelist_push: index must be declared before the debug assertion and empty-tuple check"
assert len(re.findall(r"\bPy_ssize_t\s+index\b", body)) == 1, (
    "maybe_freelist_push: exactly one index declaration required"
)
assert re.search(
    r"if \(Py_SIZE\(op\) == 0\)\s*\{\s*return 0;\s*\}\s*"
    r"index = Py_SIZE\(op\) - 1;\s*if \(index < PyTuple_NFREELISTS",
    body,
), "maybe_freelist_push: assign index at its original evaluation point after the empty-tuple return"
assert len(re.findall(r"\bindex\s*=", body)) == 1, (
    "maybe_freelist_push: exactly one index assignment required"
)
print("maybe_freelist_push index C89 declaration and evaluation order: PASS")