Fix UDfs with no parameters; fix union check

Author: kesmit13

accel.c

@@ -2179,9 +2179,6 @@ static PyObject *load_rowdat_1_numpy(PyObject *self, PyObject *args, PyObject *k
 
     // Get number of columns
     n_cols = PyObject_Length(py_colspec);
-    if (n_cols == 0) {
-        goto error;
-    }
 
     // Determine column types
     ctypes = calloc(sizeof(int), n_cols);
@@ -3979,10 +3976,6 @@ static PyObject *load_rowdat_1(PyObject *self, PyObject *args, PyObject *kwargs)
     end = data + (unsigned long long)length;
 
     colspec_l = PyObject_Length(py_colspec);
-    if (colspec_l == 0) {
-        goto error;
-    }
-
     ctypes = malloc(sizeof(int) * colspec_l);
 
     for (i = 0; i < colspec_l; i++) {

singlestoredb/functions/signature.py

@@ -6,6 +6,8 @@
 import os
 import re
 import string
+import sys
+import types
 import typing
 from typing import Any
 from typing import Callable
@@ -32,6 +34,11 @@
 from . import dtypes as dt
 from ..mysql.converters import escape_item  # type: ignore
 
+if sys.version_info >= (3, 10):
+    _UNION_TYPES = {typing.Union, types.UnionType}
+else:
+    _UNION_TYPES = {typing.Union}
+
 
 array_types: Tuple[Any, ...]
 
@@ -211,7 +218,7 @@ def simplify_dtype(dtype: Any) -> List[Any]:
     args = []
 
     # Flatten Unions
-    if origin is Union:
+    if origin in _UNION_TYPES:
         for x in typing.get_args(dtype):
             args.extend(simplify_dtype(x))