#!/usr/bin/env python3
"""Check the empty-bases declaration and preserve tuple allocation timing."""
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"if \(nbases == 0\) \{\s*PyObject \*new_bases;\s*ctx->base =",
    body,
), "type_new_get_bases: new_bases must open the empty-bases block (C89)"
assert len(re.findall(r"\bPyObject\s*\*\s*new_bases\b", body)) == 1, (
    "declare new_bases exactly once"
)
assert len(re.findall(r"\bnew_bases\s*=(?!=)", body)) == 1, (
    "assign new_bases exactly once"
)
prefix = body.split("\n    for (", 1)[0]
# Permit the separately tested C89 loop-index and winner declarations.
prefix = re.sub(
    r"\n    (?:Py_ssize_t i|PyTypeObject \*(?:winner|base));", "", prefix
)
expected = """
    Py_ssize_t nbases = PyTuple_GET_SIZE(ctx->bases);
    if (nbases == 0) {
        PyObject *new_bases;
        ctx->base = &PyBaseObject_Type;
        new_bases = PyTuple_Pack(1, ctx->base);
        if (new_bases == NULL) {
            return -1;
        }
        ctx->bases = new_bases;
        return 0;
    }
"""
assert prefix.split() == expected.split(), (
    "preserve empty-bases guard, base assignment, tuple allocation, NULL check, "
    "bases transfer, and early returns at their original evaluation points"
)
print("type_new_get_bases new_bases C89 declaration and allocation timing: PASS")