#!/usr/bin/env python3
"""Check structseq_repr's name declaration and decoding/refcount order."""
import re
import sys
from pathlib import Path

source = Path(sys.argv[1] if len(sys.argv) > 1 else "cpython/Objects/structseq.c")
match = re.search(
    r"static PyObject \*\nstructseq_repr\(PyStructSequence \*obj\)\n\{(.*?)\n\}",
    source.read_text(),
    re.S,
)
assert match, "structseq_repr definition not found"
body = match.group(1)
assert re.search(
    r"for \(i=0; i < VISIBLE_SIZE\(obj\); i\+\+\) \{"
    r"\s*const char \*name_utf8;\s*PyObject \*name;\s*if \(i > 0\)",
    body,
), "structseq_repr: VC6 requires name declared before loop-body statements"
assert len(re.findall(r"\bPyObject\s*\*name\b", body)) == 1, (
    "declare name exactly once without initialization"
)
expected = '''
        if (i > 0) {
            /* Write ", " */
            if (_PyUnicodeWriter_WriteASCIIString(&writer, ", ", 2) < 0) {
                goto error;
            }
        }

        /* Write "name=repr" */
        name_utf8 = typ->tp_members[i].name;
        if (name_utf8 == NULL) {
            PyErr_Format(PyExc_SystemError, "In structseq_repr(), member %zd name is NULL"
                         " for type %.500s", i, typ->tp_name);
            goto error;
        }

        name = PyUnicode_DecodeUTF8(name_utf8, strlen(name_utf8), NULL);
        if (name == NULL) {
            goto error;
        }
        if (_PyUnicodeWriter_WriteStr(&writer, name) < 0) {
            Py_DECREF(name);
            goto error;
        }
        Py_DECREF(name);

        if (_PyUnicodeWriter_WriteChar(&writer, '=') < 0) {
            goto error;
        }

        value = PyStructSequence_GET_ITEM(obj, i);
'''
assert re.sub(r"\s+", "", expected) in re.sub(r"\s+", "", body), (
    "preserve separator, member lookup, NULL check, decoding, write/decref, "
    "error handling, and value lookup order"
)
assert len(re.findall(r"^\s*name\s*=(?!=)", body, re.M)) == 1, "assign name exactly once"
assert body.count("Py_DECREF(name)") == 2, "preserve both name decref paths"
print("structseq_repr name C89 declaration and decoding/refcount order: PASS")