#!/usr/bin/env python3
"""Guard slice_richcompare C89 locals and allocation/refcount order."""
import re
import sys
from pathlib import Path

source = Path(sys.argv[1] if len(sys.argv) > 1 else "cpython/Objects/sliceobject.c")
match = re.search(
    r"\nslice_richcompare\(PyObject \*v, PyObject \*w, int op\)\s*\{(.*?)\n\}",
    source.read_text(),
    re.S,
)
assert match, "slice_richcompare definition not found"
body = re.sub(r"/\*.*?\*/", "", match.group(1), flags=re.S)
declarations = re.match(
    r"\s*PyObject \*t1;\s*PyObject \*t2;\s*PyObject \*res;", body
)
assert declarations, "slice_richcompare must declare t1, t2, res without initializers at function entry"

expected_statements = """
    if (!PySlice_Check(v) || !PySlice_Check(w))
        Py_RETURN_NOTIMPLEMENTED;
    if (v == w) {
        switch (op) {
        case Py_EQ:
        case Py_LE:
        case Py_GE:
            res = Py_True;
            break;
        default:
            res = Py_False;
            break;
        }
        Py_INCREF(res);
        return res;
    }
    t1 = PyTuple_Pack(3,
                     ((PySliceObject *)v)->start,
                     ((PySliceObject *)v)->stop,
                     ((PySliceObject *)v)->step);
    if (t1 == NULL) {
        return NULL;
    }
    t2 = PyTuple_Pack(3,
                     ((PySliceObject *)w)->start,
                     ((PySliceObject *)w)->stop,
                     ((PySliceObject *)w)->step);
    if (t2 == NULL) {
        Py_DECREF(t1);
        return NULL;
    }
    res = PyObject_RichCompare(t1, t2, op);
    Py_DECREF(t1);
    Py_DECREF(t2);
    return res;
"""
assert body[declarations.end():].split() == expected_statements.split(), (
    "slice_richcompare must preserve shortcut/allocation/failure/comparison/refcount order without late declarations"
)
print("slice_richcompare C89 declarations and allocation/refcount order: PASS")