Scan binary UUID to string

https://github.com/jackc/pgx/issues/1191

pgtype/uuid.go

@@ -173,6 +173,8 @@ func (UUIDCodec) PlanScan(m *Map, oid uint32, format int16, target any) ScanPlan
 		switch target.(type) {
 		case UUIDScanner:
 			return scanPlanBinaryUUIDToUUIDScanner{}
+		case TextScanner:
+			return scanPlanBinaryUUIDToTextScanner{}
 		}
 	case TextFormatCode:
 		switch target.(type) {
@@ -203,6 +205,25 @@ func (scanPlanBinaryUUIDToUUIDScanner) Scan(src []byte, dst any) error {
 	return scanner.ScanUUID(uuid)
 }
 
+type scanPlanBinaryUUIDToTextScanner struct{}
+
+func (scanPlanBinaryUUIDToTextScanner) Scan(src []byte, dst any) error {
+	scanner := (dst).(TextScanner)
+
+	if src == nil {
+		return scanner.ScanText(Text{})
+	}
+
+	if len(src) != 16 {
+		return fmt.Errorf("invalid length for UUID: %v", len(src))
+	}
+
+	var buf [16]byte
+	copy(buf[:], src)
+
+	return scanner.ScanText(Text{String: encodeUUID(buf), Valid: true})
+}
+
 type scanPlanTextAnyToUUIDScanner struct{}
 
 func (scanPlanTextAnyToUUIDScanner) Scan(src []byte, dst any) error {

pgtype/uuid_test.go

@@ -27,6 +27,11 @@ func TestUUIDCodec(t *testing.T) {
 			new(pgtype.UUID),
 			isExpectedEq(pgtype.UUID{Bytes: [16]byte{0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15}, Valid: true}),
 		},
+		{
+			pgtype.UUID{Bytes: [16]byte{0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15}, Valid: true},
+			new(string),
+			isExpectedEq("00010203-0405-0607-0809-0a0b0c0d0e0f"),
+		},
 		{pgtype.UUID{}, new([]byte), isExpectedEqBytes([]byte(nil))},
 		{pgtype.UUID{}, new(pgtype.UUID), isExpectedEq(pgtype.UUID{})},
 		{nil, new(pgtype.UUID), isExpectedEq(pgtype.UUID{})},