#!/usr/bin/env python3
"""Keep the type-spec name pointer C89-safe and initialize it after flags."""
import re
from pathlib import Path

source = Path("cpython/Objects/typeobject.c").read_text()
match = re.search(
    r"\nPyObject \*\nPyType_FromModuleAndSpec\(PyObject \*module, PyType_Spec \*spec, PyObject \*bases\)\n"
    r"\{(.*?)\n\}", source, re.S,
)
assert match, "PyType_FromModuleAndSpec definition missing"
body = re.sub(r"/\*.*?\*/|//[^\n]*", "", match.group(1), flags=re.S)
opening = body[:body.index("    nmembers = weaklistoffset")]
assert re.search(r"\bconst char \*s;", opening), (
    "s must be declared in the opening declaration block (C89), before statements"
)
assert len(re.findall(r"\bconst char\s*\*s\b", body)) == 1, "declare s exactly once"
name_setup = body[body.index("    type->tp_flags = spec->flags | Py_TPFLAGS_HEAPTYPE;"):]
name_setup = name_setup[:name_setup.index("    res->ht_name = PyUnicode_FromString(s);")]
assert len(re.findall(r"strrchr\(spec->name, '\.'\)", name_setup)) == 1, (
    "evaluate name search exactly once in name setup"
)
expected = """
    if (spec->name == NULL) {
        PyErr_SetString(PyExc_SystemError,
                        "Type spec does not define the name field.");
        goto fail;
    }
    type = &res->ht_type;
    type->tp_flags = spec->flags | Py_TPFLAGS_HEAPTYPE;
    s = strrchr(spec->name, '.');
    if (s == NULL) {
        s = spec->name;
    }
    else {
        s++;
    }
    res->ht_name = PyUnicode_FromString(s);
"""
actual = body[body.index("    if (spec->name == NULL)"):
              body.index("    if (!res->ht_name)")]
assert actual.split() == expected.split(), (
    "preserve name validation, flags, search initialization timing, and name selection"
)
print("PyType_FromModuleAndSpec s C89 declaration and same-point initialization: PASS")