#!/usr/bin/env python3
"""Keep the type-spec member loop C89-safe without moving its initialization."""
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)
assert re.search(
    r"if \(slot->slot == Py_tp_members\)\s*\{"
    r"\s*const PyMemberDef \*memb;\s*nmembers = 0;"
    r"\s*for \(memb = slot->pfunc; memb->name != NULL; memb\+\+\)\s*\{",
    body,
), "memb must be declared at block start (C89), with initialization still in the loop header"
assert len(re.findall(r"\bconst PyMemberDef\s*\*memb\b", body)) == 1, (
    "declare memb exactly once"
)
scan = body[body.index("    nmembers = weaklistoffset"):body.index("    res = (PyHeapTypeObject*)")]
expected = """
    nmembers = weaklistoffset = dictoffset = vectorcalloffset = 0;
    for (slot = spec->slots; slot->slot; slot++) {
        if (slot->slot == Py_tp_members) {
            const PyMemberDef *memb;
            nmembers = 0;
            for (memb = slot->pfunc; memb->name != NULL; memb++) {
                nmembers++;
                if (strcmp(memb->name, "__weaklistoffset__") == 0) {
                    assert(memb->type == T_PYSSIZET);
                    assert(memb->flags == READONLY);
                    weaklistoffset = memb->offset;
                }
                if (strcmp(memb->name, "__dictoffset__") == 0) {
                    assert(memb->type == T_PYSSIZET);
                    assert(memb->flags == READONLY);
                    dictoffset = memb->offset;
                }
                if (strcmp(memb->name, "__vectorcalloffset__") == 0) {
                    assert(memb->type == T_PYSSIZET);
                    assert(memb->flags == READONLY);
                    vectorcalloffset = memb->offset;
                }
            }
        }
    }
"""
assert scan.split() == expected.split(), (
    "preserve member scan guards, evaluation order, bounds, increments, and offset handling"
)
print("PyType_FromModuleAndSpec memb C89 declaration and same-point initialization: PASS")