fix: apply suggestions

Signed-off-by: yihong0618 <zouzou0208@gmail.com>

Author: yihong0618

Modules/_io/textio.c

@@ -2416,22 +2416,13 @@ typedef struct {
 #endif
 
 static int
-textiowrapper_parse_cookie(textio *self, cookie_type *cookie, PyObject *cookieObj)
+textiowrapper_parse_cookie(cookie_type *cookie, PyObject *cookieObj)
 {
     unsigned char buffer[COOKIE_BUF_LEN];
     PyLongObject *cookieLong = (PyLongObject *)PyNumber_Long(cookieObj);
     if (cookieLong == NULL)
         return -1;
 
-    // gh-143007: PyNumber_Long can call arbitrary code through __int__
-    // which may detach the underlying buffer.
-    if (self->detached) {
-        Py_DECREF(cookieLong);
-        PyErr_SetString(PyExc_ValueError,
-                        "underlying buffer has been detached");
-        return -1;
-    }
-
     if (_PyLong_AsByteArray(cookieLong, buffer, sizeof(buffer),
                             PY_LITTLE_ENDIAN, 0, 1) < 0) {
         Py_DECREF(cookieLong);
@@ -2646,13 +2637,17 @@ _io_TextIOWrapper_seek_impl(textio *self, PyObject *cookieObj, int whence)
     /* The strategy of seek() is to go back to the safe start point
      * and replay the effect of read(chars_to_skip) from there.
      */
-    if (textiowrapper_parse_cookie(self, &cookie, cookieObj) < 0)
+    if (textiowrapper_parse_cookie(&cookie, cookieObj) < 0)
         goto fail;
 
     /* Seek back to the safe start point. */
     posobj = PyLong_FromOff_t(cookie.start_pos);
     if (posobj == NULL)
         goto fail;
+
+    // gh-143007 PyNumber_Long can call arbitrary code through __int__ which may detach the underlying buffer.
+    // So we need to re-check that the TextIOWrapper is still attached.
+    CHECK_ATTACHED(self);
     res = PyObject_CallMethodOneArg(self->buffer, &_Py_ID(seek), posobj);
     Py_DECREF(posobj);
     if (res == NULL)
@@ -2691,7 +2686,6 @@ _io_TextIOWrapper_seek_impl(textio *self, PyObject *cookieObj, int whence)
             goto fail;
         }
         Py_XSETREF(self->snapshot, snapshot);
-
         decoded = PyObject_CallMethodObjArgs(self->decoder, &_Py_ID(decode),
             input_chunk, cookie.need_eof ? Py_True : Py_False, NULL);