#!/usr/bin/env python3
"""Check PyType_Modified's ref/obj declarations and unchanged use order."""
import re
from pathlib import Path

source = Path("cpython/Objects/typeobject.c").read_text()
match = re.search(
    r"\nvoid\nPyType_Modified\(PyTypeObject \*type\)\n\{(.*?)\n\}",
    source,
    re.S,
)
assert match, "PyType_Modified definition missing"
body = re.sub(r"/\*.*?\*/", "", match.group(1), flags=re.S)
assert re.match(
    r"\s*PyObject \*subclasses;\s*Py_ssize_t i;\s*PyObject \*ref;",
    body,
), "PyType_Modified: PyObject *ref; must be in the opening declaration block"
assert len(re.findall(r"\bPyObject\s*\*\s*ref\b", body)) == 1, (
    "PyType_Modified: declare ref exactly once without initialization"
)
assert re.match(
    r"\s*PyObject \*subclasses;\s*Py_ssize_t i;\s*PyObject \*ref;\s*"
    r"PyObject \*obj;",
    body,
), "PyType_Modified: PyObject *obj; must be in the opening declaration block"
assert len(re.findall(r"\bPyObject\s*\*\s*obj\b", body)) == 1, (
    "PyType_Modified: declare obj exactly once without initialization"
)
assert re.fullmatch(
    r"\s*PyObject \*subclasses;\s*Py_ssize_t i;\s*PyObject \*ref;\s*"
    r"PyObject \*obj;\s*"
    r"if \(!_PyType_HasFeature\(type, Py_TPFLAGS_VALID_VERSION_TAG\)\) \{\s*"
    r"return;\s*\}\s*"
    r"subclasses = type->tp_subclasses;\s*"
    r"if \(subclasses != NULL\) \{\s*"
    r"assert\(PyDict_CheckExact\(subclasses\)\);\s*i = 0;\s*"
    r"while \(PyDict_Next\(subclasses, &i, NULL, &ref\)\) \{\s*"
    r"assert\(PyWeakref_CheckRef\(ref\)\);\s*"
    r"obj = PyWeakref_GET_OBJECT\(ref\);\s*"
    r"if \(obj == Py_None\) \{\s*continue;\s*\}\s*"
    r"PyType_Modified\(_PyType_CAST\(obj\)\);\s*\}\s*\}\s*"
    r"type->tp_flags &= ~Py_TPFLAGS_VALID_VERSION_TAG;\s*"
    r"type->tp_version_tag = 0;\s*",
    body,
), "PyType_Modified: preserve all assignments, uses and evaluation order"
print("PyType_Modified ref/obj C89 declarations and unchanged use order: PASS")