#!/usr/bin/env python3
"""Regress VC6 C89 compatibility of type_new_get_bases() loop index."""
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.match(
    r"\s*Py_ssize_t nbases = PyTuple_GET_SIZE\(ctx->bases\);"
    r"\s*Py_ssize_t i;\s*PyTypeObject \*winner;\s*PyTypeObject \*base;"
    r"\s*if \(nbases == 0\)",
    body,
), "type_new_get_bases: C89 loop index i must be declared before statements"
assert len(re.findall(r"\bPy_ssize_t\s+i\b", body)) == 1, "declare i exactly once"
assert re.search(
    r"for \(i = 0; i < nbases; i\+\+\) \{\s*"
    r"PyObject \*base = PyTuple_GET_ITEM\(ctx->bases, i\);",
    body,
), "type_new_get_bases: preserve loop start, bound, increment, and base lookup"
assert not re.search(r"for\s*\(\s*Py_ssize_t\b", body), (
    "type_new_get_bases: loop initializer must reuse the declared index"
)
print("type_new_get_bases C89 loop index: PASS")