#!/usr/bin/env python3
"""Check tuple_alloc's C89 declaration and validation/allocation 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 PyTupleObject \*\ntuple_alloc\(Py_ssize_t size\)\n\{(.*?)\n\}",
    source.read_text(),
    re.S,
)
assert match, "tuple_alloc definition not found"
body = match.group(1)
assert re.match(r"\s*PyTupleObject \*op;", body), (
    "tuple_alloc: op must be declared without initializer before the size check; "
    "declaration after statement is not C89 compatible"
)
expected = """
    PyTupleObject *op;
    if (size < 0) {
        PyErr_BadInternalCall();
        return NULL;
    }
#ifdef Py_DEBUG
    assert(size != 0);    // The empty tuple is statically allocated.
#endif

    op = maybe_freelist_pop(size);
    if (op == NULL) {
        /* Check for overflow */
        if ((size_t)size > ((size_t)PY_SSIZE_T_MAX - (sizeof(PyTupleObject) -
                    sizeof(PyObject *))) / sizeof(PyObject *)) {
            return (PyTupleObject *)PyErr_NoMemory();
        }
        op = PyObject_GC_NewVar(PyTupleObject, &PyTuple_Type, size);
        if (op == NULL)
            return NULL;
    }
    return op;
"""
assert re.sub(r"\s+", "", body) == re.sub(r"\s+", "", expected), (
    "preserve size validation, debug assertion, single freelist lookup, overflow "
    "check, GC allocation, error/return order, and absence of refcount operations"
)
print("tuple_alloc C89 declaration and validation/allocation order: PASS")