Handle NULL values in UniqueIdentifier.Scan()

README.md

@@ -477,6 +477,7 @@ Constrain the provider to an allowed list of key vaults by appending vault host
 * Supports connections to AlwaysOn Availability Group listeners, including re-direction to read-only replicas.
 * Supports query notifications
 * Supports Kerberos Authentication
+* Supports handling the `uniqueidentifier` data type with the `UniqueIdentifier` and `NullUniqueIdentifier` go types
 * Pluggable Dialer implementations through `msdsn.ProtocolParsers` and `msdsn.ProtocolDialers`
 * A `namedpipe` package to support connections using named pipes (np:) on Windows
 * A `sharedmemory` package to support connections using shared memory (lpc:) on Windows

bulkcopy_test.go

@@ -68,6 +68,7 @@ func TestBulkcopy(t *testing.T) {
 		{"test_intf32", float32(1234.56), 1234},
 		{"test_geom", geom, string(geom)},
 		{"test_uniqueidentifier", uid, string(uid)},
+		{"test_nulluniqueidentifier", nil, nil},
 		// {"test_smallmoney", 1234.56, nil},
 		// {"test_money", 1234.56, nil},
 		{"test_decimal_18_0", 1234.0001, "1234"},
@@ -270,6 +271,7 @@ func setupTable(ctx context.Context, t *testing.T, conn *sql.Conn, tableName str
 	[test_geog] [geography] NULL,
 	[text_xml] [xml] NULL,
 	[test_uniqueidentifier] [uniqueidentifier] NULL,
+	[test_nulluniqueidentifier] [uniqueidentifier] NULL,
 	[test_decimal_18_0] [decimal](18, 0) NULL,
 	[test_decimal_18_2] [decimal](18, 2) NULL,
 	[test_decimal_9_2] [decimal](9, 2) NULL,

uniqueidentifier_null.go

@@ -0,0 +1,65 @@
+package mssql
+
+import (
+	"database/sql/driver"
+)
+
+type NullUniqueIdentifier struct {
+	UUID  UniqueIdentifier
+	Valid bool // Valid is true if UUID is not NULL
+}
+
+func (n *NullUniqueIdentifier) Scan(v interface{}) error {
+	if v == nil {
+		*n = NullUniqueIdentifier{
+			UUID:  [16]byte{0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0},
+			Valid: false,
+		}
+		return nil
+	}
+	u := n.UUID
+	err := u.Scan(v)
+	*n = NullUniqueIdentifier{
+		UUID:  u,
+		Valid: true,
+	}
+	return err
+}
+
+func (n NullUniqueIdentifier) Value() (driver.Value, error) {
+	if !n.Valid {
+		return nil, nil
+	}
+	return n.UUID.Value()
+}
+
+func (n NullUniqueIdentifier) String() string {
+	if !n.Valid {
+		return "NULL"
+	}
+	return n.UUID.String()
+}
+
+func (n NullUniqueIdentifier) MarshalText() (text []byte, err error) {
+	if !n.Valid {
+		return []byte("null"), nil
+	}
+	return n.UUID.MarshalText()
+}
+
+func (n *NullUniqueIdentifier) UnmarshalJSON(b []byte) error {
+	u := n.UUID
+	if string(b) == "null" {
+		*n = NullUniqueIdentifier{
+			UUID:  [16]byte{0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0},
+			Valid: false,
+		}
+		return nil
+	}
+	err := u.UnmarshalJSON(b)
+	*n = NullUniqueIdentifier{
+		UUID:  u,
+		Valid: true,
+	}
+	return err
+}

uniqueidentifier_null_test.go

@@ -0,0 +1,215 @@
+package mssql
+
+import (
+	"bytes"
+	"database/sql"
+	"database/sql/driver"
+	"fmt"
+	"reflect"
+	"testing"
+)
+
+func TestNullableUniqueIdentifierScanNull(t *testing.T) {
+	t.Parallel()
+	nullUUID := NullUniqueIdentifier{
+		UUID:  [16]byte{0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0},
+		Valid: false,
+	}
+
+	sut := NullUniqueIdentifier{
+		UUID:  [16]byte{0x1},
+		Valid: true,
+	}
+	scanErr := sut.Scan(nil) // NULL in the DB
+	if scanErr != nil {
+		t.Fatal("NullUniqueIdentifier should not error out on Scan(nil)")
+	}
+	if sut != nullUUID {
+		t.Errorf("bytes not swapped correctly: got %q; want %q", sut, nullUUID)
+	}
+}
+
+func TestNullableUniqueIdentifierScanBytes(t *testing.T) {
+	t.Parallel()
+	dbUUID := [16]byte{0x67, 0x45, 0x23, 0x01, 0xAB, 0x89, 0xEF, 0xCD, 0x01, 0x23, 0x45, 0x67, 0x89, 0xAB, 0xCD, 0xEF}
+	uuid := NullUniqueIdentifier{
+		UUID:  [16]byte{0x01, 0x23, 0x45, 0x67, 0x89, 0xAB, 0xCD, 0xEF, 0x01, 0x23, 0x45, 0x67, 0x89, 0xAB, 0xCD, 0xEF},
+		Valid: true,
+	}
+
+	var sut NullUniqueIdentifier
+	scanErr := sut.Scan(dbUUID[:])
+	if scanErr != nil {
+		t.Fatal(scanErr)
+	}
+	if sut != uuid {
+		t.Errorf("bytes not swapped correctly: got %q; want %q", sut, uuid)
+	}
+}
+
+func TestNullableUniqueIdentifierScanString(t *testing.T) {
+	t.Parallel()
+	uuid := NullUniqueIdentifier{
+		UUID:  [16]byte{0x01, 0x23, 0x45, 0x67, 0x89, 0xAB, 0xCD, 0xEF, 0x01, 0x23, 0x45, 0x67, 0x89, 0xAB, 0xCD, 0xEF},
+		Valid: true,
+	}
+
+	var sut NullUniqueIdentifier
+	scanErr := sut.Scan(uuid.String())
+	if scanErr != nil {
+		t.Fatal(scanErr)
+	}
+	if sut != uuid {
+		t.Errorf("string not scanned correctly: got %q; want %q", sut, uuid)
+	}
+}
+
+func TestNullableUniqueIdentifierScanUnexpectedType(t *testing.T) {
+	t.Parallel()
+	var sut NullUniqueIdentifier
+	scanErr := sut.Scan(int(1))
+	if scanErr == nil {
+		t.Fatal(scanErr)
+	}
+}
+
+func TestNullableUniqueIdentifierValue(t *testing.T) {
+	t.Parallel()
+	dbUUID := [16]byte{0x67, 0x45, 0x23, 0x01, 0xAB, 0x89, 0xEF, 0xCD, 0x01, 0x23, 0x45, 0x67, 0x89, 0xAB, 0xCD, 0xEF}
+
+	uuid := NullUniqueIdentifier{
+		UUID:  [16]byte{0x01, 0x23, 0x45, 0x67, 0x89, 0xAB, 0xCD, 0xEF, 0x01, 0x23, 0x45, 0x67, 0x89, 0xAB, 0xCD, 0xEF},
+		Valid: true,
+	}
+
+	sut := uuid
+	v, valueErr := sut.Value()
+	if valueErr != nil {
+		t.Fatal(valueErr)
+	}
+
+	b, ok := v.([]byte)
+	if !ok {
+		t.Fatalf("(%T) is not []byte", v)
+	}
+
+	if !bytes.Equal(b, dbUUID[:]) {
+		t.Errorf("got %q; want %q", b, dbUUID)
+	}
+}
+
+func TestNullableUniqueIdentifierValueNull(t *testing.T) {
+	t.Parallel()
+	uuid := NullUniqueIdentifier{
+		UUID:  [16]byte{0x01, 0x23, 0x45, 0x67, 0x89, 0xAB, 0xCD, 0xEF, 0x01, 0x23, 0x45, 0x67, 0x89, 0xAB, 0xCD, 0xEF},
+		Valid: false,
+	}
+
+	sut := uuid
+	v, valueErr := sut.Value()
+	if valueErr != nil {
+		t.Errorf("unexpected error for invalid uuid: %s", valueErr)
+	}
+
+	if v != nil {
+		t.Errorf("expected non-nil value for invalid uuid: %s", v)
+	}
+}
+
+func TestNullableUniqueIdentifierString(t *testing.T) {
+	t.Parallel()
+	sut := NullUniqueIdentifier{
+		UUID:  [16]byte{0x01, 0x23, 0x45, 0x67, 0x89, 0xAB, 0xCD, 0xEF, 0x01, 0x23, 0x45, 0x67, 0x89, 0xAB, 0xCD, 0xEF},
+		Valid: true,
+	}
+	expected := "01234567-89AB-CDEF-0123-456789ABCDEF"
+	if actual := sut.String(); actual != expected {
+		t.Errorf("sut.String() = %s; want %s", sut, expected)
+	}
+}
+
+func TestNullableUniqueIdentifierStringNull(t *testing.T) {
+	t.Parallel()
+	sut := NullUniqueIdentifier{
+		UUID:  [16]byte{0x01, 0x23, 0x45, 0x67, 0x89, 0xAB, 0xCD, 0xEF, 0x01, 0x23, 0x45, 0x67, 0x89, 0xAB, 0xCD, 0xEF},
+		Valid: false,
+	}
+	expected := "NULL"
+	if actual := sut.String(); actual != expected {
+		t.Errorf("sut.String() = %s; want %s", sut, expected)
+	}
+}
+
+func TestNullableUniqueIdentifierMarshalText(t *testing.T) {
+	t.Parallel()
+	sut := NullUniqueIdentifier{
+		UUID:  [16]byte{0x01, 0x23, 0x45, 0x67, 0x89, 0xAB, 0xCD, 0xEF, 0x01, 0x23, 0x45, 0x67, 0x89, 0xAB, 0xCD, 0xEF},
+		Valid: true,
+	}
+	expected := []byte{48, 49, 50, 51, 52, 53, 54, 55, 45, 56, 57, 65, 66, 45, 67, 68, 69, 70, 45, 48, 49, 50, 51, 45, 52, 53, 54, 55, 56, 57, 65, 66, 67, 68, 69, 70}
+	text, marshalErr := sut.MarshalText()
+	if marshalErr != nil {
+		t.Errorf("unexpected error while marshalling: %s", marshalErr)
+	}
+	if actual := text; !reflect.DeepEqual(actual, expected) {
+		t.Errorf("sut.MarshalText() = %v; want %v", actual, expected)
+	}
+}
+
+func TestNullableUniqueIdentifierMarshalTextNull(t *testing.T) {
+	t.Parallel()
+	sut := NullUniqueIdentifier{
+		UUID:  [16]byte{0x01, 0x23, 0x45, 0x67, 0x89, 0xAB, 0xCD, 0xEF, 0x01, 0x23, 0x45, 0x67, 0x89, 0xAB, 0xCD, 0xEF},
+		Valid: false,
+	}
+	expected := []byte("null")
+	text, marshalErr := sut.MarshalText()
+	if marshalErr != nil {
+		t.Errorf("unexpected error while marshalling: %s", marshalErr)
+	}
+	if actual := text; !reflect.DeepEqual(actual, expected) {
+		t.Errorf("sut.MarshalText() = %v; want %v", actual, expected)
+	}
+}
+
+func TestNullableUniqueIdentifierUnmarshalJSON(t *testing.T) {
+	t.Parallel()
+	input := []byte("01234567-89AB-CDEF-0123-456789ABCDEF")
+	var u NullUniqueIdentifier
+
+	err := u.UnmarshalJSON(input)
+	if err != nil {
+		t.Fatal(err)
+	}
+	expected := NullUniqueIdentifier{
+		UUID:  [16]byte{0x01, 0x23, 0x45, 0x67, 0x89, 0xAB, 0xCD, 0xEF, 0x01, 0x23, 0x45, 0x67, 0x89, 0xAB, 0xCD, 0xEF},
+		Valid: true,
+	}
+	if u != expected {
+		t.Errorf("u.UnmarshalJSON() = %v; want %v", u, expected)
+	}
+}
+
+func TestNullableUniqueIdentifierUnmarshalJSONNull(t *testing.T) {
+	t.Parallel()
+	u := NullUniqueIdentifier{
+		UUID:  [16]byte{0x01, 0x23, 0x45, 0x67, 0x89, 0xAB, 0xCD, 0xEF, 0x01, 0x23, 0x45, 0x67, 0x89, 0xAB, 0xCD, 0xEF},
+		Valid: true,
+	}
+
+	err := u.UnmarshalJSON([]byte("null"))
+	if err != nil {
+		t.Fatal(err)
+	}
+	expected := NullUniqueIdentifier{
+		UUID:  [16]byte{0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0},
+		Valid: false,
+	}
+	if u != expected {
+		t.Errorf("u.UnmarshalJSON() = %v; want %v", u, expected)
+	}
+}
+
+var _ fmt.Stringer = NullUniqueIdentifier{}
+var _ sql.Scanner = &NullUniqueIdentifier{}
+var _ driver.Valuer = NullUniqueIdentifier{}