feat(duckdb): forward UDF configuration dict as kwargs during registration (#10358)

Co-authored-by: Phillip Cloud <[email protected]>

Author: NickCrews

ibis/backends/duckdb/__init__.py

@@ -1735,22 +1735,20 @@ def _register_udfs(self, expr: ir.Expr) -> None:
                 registration_func(con)
 
     def _register_udf(self, udf_node: ops.ScalarUDF):
-        func = udf_node.__func__
-        name = type(udf_node).__name__
         type_mapper = self.compiler.type_mapper
         input_types = [
             type_mapper.to_string(param.annotation.pattern.dtype)
             for param in udf_node.__signature__.parameters.values()
         ]
-        output_type = type_mapper.to_string(udf_node.dtype)
 
         def register_udf(con):
             return con.create_function(
-                name,
-                func,
-                input_types,
-                output_type,
+                name=type(udf_node).__name__,
+                function=udf_node.__func__,
+                parameters=input_types,
+                return_type=type_mapper.to_string(udf_node.dtype),
                 type=_UDF_INPUT_TYPE_MAPPING[udf_node.__input_type__],
+                **udf_node.__config__,
             )
 
         return register_udf

ibis/backends/duckdb/tests/test_udf.py

@@ -1,8 +1,10 @@
 from __future__ import annotations
 
+import duckdb
 import pytest
 from pytest import param
 
+import ibis
 from ibis import udf
 
 
@@ -103,3 +105,29 @@ def dont_intercept_null(x: int) -> int:
 )
 def test_dont_intercept_null(con, expr, expected):
     assert con.execute(expr) == expected
+
+
+def test_kwargs_are_forwarded(con):
+    def nullify_two(x: int) -> int:
+        return None if x == 2 else x
+
+    @udf.scalar.python
+    def no_kwargs(x: int) -> int:
+        return nullify_two(x)
+
+    @udf.scalar.python(null_handling="special")
+    def with_kwargs(x: int) -> int:
+        return nullify_two(x)
+
+    # If we return go Non-NULL -> Non-NULL, then passing null_handling="special"
+    # will not change the result
+    assert con.execute(no_kwargs(ibis.literal(1))) == 1
+    assert con.execute(with_kwargs(ibis.literal(1))) == 1
+
+    # But, if our UDF ever goes Non-NULL -> NULL, then we NEED to pass
+    # null_handling="special", otherwise duckdb throws an error
+    assert con.execute(with_kwargs(ibis.literal(2))) is None
+
+    expr = no_kwargs(ibis.literal(2))
+    with pytest.raises(duckdb.InvalidInputException):
+        con.execute(expr)