adding ANY

errors.go

@@ -105,6 +105,7 @@ var (
 	errScalarUDFEmptyInputTypes = fmt.Errorf("%w: empty input types", errScalarUDFCreate)
 	errScalarUDFInputTypeIsNil  = fmt.Errorf("%w: input type is nil", errScalarUDFCreate)
 	errScalarUDFResultTypeIsNil = fmt.Errorf("%w: result type is nil", errScalarUDFCreate)
+	errScalarUDFResultTypeIsANY = fmt.Errorf("%w: result type is ANY", errScalarUDFCreate)
 
 	// Errors not covered in tests.
 	errConnect      = errors.New("could not connect to database")

scalar_udf.go

@@ -23,6 +23,8 @@ type ScalarFunctionConfig interface {
 	InputTypeInfos() []TypeInfo
 	ResultTypeInfo() TypeInfo
 	VariadicTypeInfo() TypeInfo
+	Volatile() bool
+	SpecialNullHandling() bool
 }
 
 type ScalarFunction interface {
@@ -126,6 +128,9 @@ func registerResultParameters(config ScalarFunctionConfig, scalarFunction C.duck
 	if config.ResultTypeInfo() == nil {
 		return errScalarUDFResultTypeIsNil
 	}
+	if config.ResultTypeInfo().InternalType() == TYPE_ANY {
+		return errScalarUDFResultTypeIsANY
+	}
 	logicalType := config.ResultTypeInfo().logicalType()
 	C.duckdb_scalar_function_set_return_type(scalarFunction, logicalType)
 	C.duckdb_destroy_logical_type(&logicalType)
@@ -153,17 +158,20 @@ func RegisterScalarUDF(c *sql.Conn, name string, f ScalarFunction) error {
 		scalarFunction := C.duckdb_create_scalar_function()
 		C.duckdb_scalar_function_set_name(scalarFunction, functionName)
 
-		// Get the configuration.
+		// Configure the scalar function.
 		config := f.Config()
-
-		// Register the input parameters.
 		if err := registerInputParameters(config, scalarFunction); err != nil {
 			return getError(errAPI, err)
 		}
-		// Register the result parameters.
 		if err := registerResultParameters(config, scalarFunction); err != nil {
 			return getError(errAPI, err)
 		}
+		if config.SpecialNullHandling() {
+			C.duckdb_scalar_function_set_special_handling(scalarFunction)
+		}
+		if config.Volatile() {
+			C.duckdb_scalar_function_set_volatile(scalarFunction)
+		}
 
 		// Set the function callback.
 		C.duckdb_scalar_function_set_function(scalarFunction, C.scalar_udf_callback_t(C.scalar_udf_callback))

scalar_udf_test.go

@@ -29,6 +29,14 @@ func (*simpleScalarUDFConfig) VariadicTypeInfo() TypeInfo {
 	return nil
 }
 
+func (*simpleScalarUDFConfig) Volatile() bool {
+	return false
+}
+
+func (*simpleScalarUDFConfig) SpecialNullHandling() bool {
+	return false
+}
+
 func (*simpleScalarUDF) Config() ScalarFunctionConfig {
 	return &simpleScalarUDFConfig{}
 }
@@ -88,6 +96,14 @@ func (*allTypesScalarUDFConfig) VariadicTypeInfo() TypeInfo {
 	return nil
 }
 
+func (*allTypesScalarUDFConfig) Volatile() bool {
+	return false
+}
+
+func (*allTypesScalarUDFConfig) SpecialNullHandling() bool {
+	return false
+}
+
 func (*allTypesScalarUDF) Config() ScalarFunctionConfig {
 	return &allTypesScalarUDFConfig{}
 }
@@ -144,6 +160,14 @@ func (*variadicScalarUDFConfig) VariadicTypeInfo() TypeInfo {
 	return currentInfo
 }
 
+func (*variadicScalarUDFConfig) Volatile() bool {
+	return true
+}
+
+func (*variadicScalarUDFConfig) SpecialNullHandling() bool {
+	return true
+}
+
 func (*variadicScalarUDF) Config() ScalarFunctionConfig {
 	return &variadicScalarUDFConfig{}
 }
@@ -198,6 +222,90 @@ func TestVariadicScalarUDF(t *testing.T) {
 	require.NoError(t, db.Close())
 }
 
+type anyScalarUDF struct{}
+
+type anyScalarUDFConfig struct{}
+
+func (*anyScalarUDFConfig) InputTypeInfos() []TypeInfo {
+	return nil
+}
+
+func (*anyScalarUDFConfig) ResultTypeInfo() TypeInfo {
+	return currentInfo
+}
+
+func (*anyScalarUDFConfig) VariadicTypeInfo() TypeInfo {
+	info, err := NewTypeInfo(TYPE_ANY)
+	if err != nil {
+		panic(err)
+	}
+	return info
+}
+
+func (*anyScalarUDFConfig) Volatile() bool {
+	return true
+}
+
+func (*anyScalarUDFConfig) SpecialNullHandling() bool {
+	return true
+}
+
+func (*anyScalarUDF) Config() ScalarFunctionConfig {
+	return &anyScalarUDFConfig{}
+}
+
+func (*anyScalarUDF) ExecuteRow(args []driver.Value) (any, error) {
+	count := int32(0)
+	for _, val := range args {
+		if val == nil {
+			count++
+		}
+	}
+	return count, nil
+}
+
+func TestANYScalarUDF(t *testing.T) {
+	// TODO: once DuckDB has SQLNull type.
+	return
+
+	db, err := sql.Open("duckdb", "")
+	require.NoError(t, err)
+
+	c, err := db.Conn(context.Background())
+	require.NoError(t, err)
+
+	currentInfo, err = NewTypeInfo(TYPE_INTEGER)
+	require.NoError(t, err)
+
+	var udf *anyScalarUDF
+	err = RegisterScalarUDF(c, "my_null_count", udf)
+	require.NoError(t, err)
+
+	var count int
+	row := db.QueryRow(`SELECT my_null_count(10, 42, 2, 2, 2) AS msg`)
+	require.NoError(t, row.Scan(&count))
+	require.Equal(t, 0, count)
+
+	row = db.QueryRow(`SELECT my_null_count(10, NULL, NULL) AS msg`)
+	require.NoError(t, row.Scan(&count))
+	require.Equal(t, 2, count)
+
+	row = db.QueryRow(`SELECT my_null_count(10) AS msg`)
+	require.NoError(t, row.Scan(&count))
+	require.Equal(t, 0, count)
+
+	row = db.QueryRow(`SELECT my_null_count(NULL) AS msg`)
+	require.NoError(t, row.Scan(&count))
+	require.Equal(t, 1, count)
+
+	row = db.QueryRow(`SELECT my_null_count() AS msg`)
+	require.NoError(t, row.Scan(&count))
+	require.Equal(t, 0, count)
+
+	require.NoError(t, c.Close())
+	require.NoError(t, db.Close())
+}
+
 type errNilInputScalarUDF struct{}
 
 type errNilInputScalarUDFConfig struct{}
@@ -214,6 +322,14 @@ func (*errNilInputScalarUDFConfig) VariadicTypeInfo() TypeInfo {
 	return nil
 }
 
+func (*errNilInputScalarUDFConfig) Volatile() bool {
+	return false
+}
+
+func (*errNilInputScalarUDFConfig) SpecialNullHandling() bool {
+	return false
+}
+
 func (*errNilInputScalarUDF) Config() ScalarFunctionConfig {
 	return &errNilInputScalarUDFConfig{}
 }
@@ -238,6 +354,14 @@ func (*errEmptyInputScalarUDFConfig) VariadicTypeInfo() TypeInfo {
 	return nil
 }
 
+func (*errEmptyInputScalarUDFConfig) Volatile() bool {
+	return false
+}
+
+func (*errEmptyInputScalarUDFConfig) SpecialNullHandling() bool {
+	return false
+}
+
 func (*errEmptyInputScalarUDF) Config() ScalarFunctionConfig {
 	return &errEmptyInputScalarUDFConfig{}
 }
@@ -262,6 +386,14 @@ func (*errInputIsNilScalarUDFConfig) VariadicTypeInfo() TypeInfo {
 	return nil
 }
 
+func (*errInputIsNilScalarUDFConfig) Volatile() bool {
+	return false
+}
+
+func (*errInputIsNilScalarUDFConfig) SpecialNullHandling() bool {
+	return false
+}
+
 func (*errInputIsNilScalarUDF) Config() ScalarFunctionConfig {
 	return &errInputIsNilScalarUDFConfig{}
 }
@@ -286,6 +418,14 @@ func (*errResultIsNilScalarUDFConfig) VariadicTypeInfo() TypeInfo {
 	return nil
 }
 
+func (*errResultIsNilScalarUDFConfig) Volatile() bool {
+	return false
+}
+
+func (*errResultIsNilScalarUDFConfig) SpecialNullHandling() bool {
+	return false
+}
+
 func (*errResultIsNilScalarUDF) Config() ScalarFunctionConfig {
 	return &errResultIsNilScalarUDFConfig{}
 }
@@ -294,6 +434,42 @@ func (*errResultIsNilScalarUDF) ExecuteRow([]driver.Value) (any, error) {
 	return nil, nil
 }
 
+type errResultIsANYScalarUDF struct{}
+
+type errResultIsANYScalarUDFConfig struct{}
+
+func (*errResultIsANYScalarUDFConfig) InputTypeInfos() []TypeInfo {
+	return []TypeInfo{currentInfo}
+}
+
+func (*errResultIsANYScalarUDFConfig) ResultTypeInfo() TypeInfo {
+	info, err := NewTypeInfo(TYPE_ANY)
+	if err != nil {
+		panic(err)
+	}
+	return info
+}
+
+func (*errResultIsANYScalarUDFConfig) VariadicTypeInfo() TypeInfo {
+	return nil
+}
+
+func (*errResultIsANYScalarUDFConfig) Volatile() bool {
+	return false
+}
+
+func (*errResultIsANYScalarUDFConfig) SpecialNullHandling() bool {
+	return false
+}
+
+func (*errResultIsANYScalarUDF) Config() ScalarFunctionConfig {
+	return &errResultIsANYScalarUDFConfig{}
+}
+
+func (*errResultIsANYScalarUDF) ExecuteRow([]driver.Value) (any, error) {
+	return nil, nil
+}
+
 type errExecScalarUDF struct{}
 
 func (*errExecScalarUDF) Config() ScalarFunctionConfig {
@@ -336,10 +512,16 @@ func TestScalarUDFErrors(t *testing.T) {
 	err = RegisterScalarUDF(c, "err_input_type_is_nil", errInputIsNilUDF)
 	testError(t, err, errAPI.Error(), errScalarUDFCreate.Error(), errScalarUDFInputTypeIsNil.Error())
 
+	// Invalid result parameters.
+
 	var errResultIsNil *errResultIsNilScalarUDF
 	err = RegisterScalarUDF(c, "err_result_type_is_nil", errResultIsNil)
 	testError(t, err, errAPI.Error(), errScalarUDFCreate.Error(), errScalarUDFResultTypeIsNil.Error())
 
+	var errResultIsANY *errResultIsANYScalarUDF
+	err = RegisterScalarUDF(c, "err_result_type_is_any", errResultIsANY)
+	testError(t, err, errAPI.Error(), errScalarUDFCreate.Error(), errScalarUDFResultTypeIsANY.Error())
+
 	// Error during execution.
 	var errExecUDF *errExecScalarUDF
 	err = RegisterScalarUDF(c, "err_exec", errExecUDF)