Fix/driver value conversion

gonull.go

@@ -7,6 +7,7 @@ import (
 	"database/sql/driver"
 	"encoding/json"
 	"errors"
+	"fmt"
 	"reflect"
 )
 
@@ -68,7 +69,54 @@ func (n Nullable[T]) Value() (driver.Value, error) {
 	if valuer, ok := interface{}(n.Val).(driver.Valuer); ok {
 		return valuer.Value()
 	}
-	return n.Val, nil
+
+	return convertToDriverValue(n.Val)
+}
+
+func convertToDriverValue(v any) (driver.Value, error) {
+	if valuer, ok := v.(driver.Valuer); ok {
+		return valuer.Value()
+	}
+
+	rv := reflect.ValueOf(v)
+	switch rv.Kind() {
+	case reflect.Pointer:
+		if rv.IsNil() {
+			return nil, nil
+		}
+		return convertToDriverValue(rv.Elem().Interface())
+
+	case reflect.Int, reflect.Int8, reflect.Int16, reflect.Int32, reflect.Int64:
+		return rv.Int(), nil
+
+	case reflect.Uint, reflect.Uint8, reflect.Uint16, reflect.Uint32:
+		return int64(rv.Uint()), nil
+
+	case reflect.Uint64:
+		u64 := rv.Uint()
+		if u64 >= 1<<63 {
+			return nil, fmt.Errorf("uint64 values with high bit set are not supported")
+		}
+		return int64(u64), nil
+
+	case reflect.Float32, reflect.Float64:
+		return rv.Float(), nil
+
+	case reflect.Bool:
+		return rv.Bool(), nil
+
+	case reflect.Slice:
+		if rv.Type().Elem().Kind() == reflect.Uint8 {
+			return rv.Bytes(), nil
+		}
+		return nil, fmt.Errorf("unsupported slice type: %s", rv.Type().Elem().Kind())
+
+	case reflect.String:
+		return rv.String(), nil
+
+	default:
+		return nil, fmt.Errorf("unsupported type: %T", v)
+	}
 }
 
 // UnmarshalJSON implements the json.Unmarshaler interface for Nullable, allowing it to be used as a nullable field in JSON operations.

gonull_test.go

@@ -5,6 +5,7 @@ import (
 	"encoding/json"
 	"errors"
 	"fmt"
+	"reflect"
 	"testing"
 
 	"github.com/stretchr/testify/assert"
@@ -495,3 +496,99 @@ func TestValuerAndScanner(t *testing.T) {
 		Val:     testValuerScannerStruct{},
 	}, scannerNullableUnsupported)
 }
+
+type customValuer struct {
+	value any
+	err   error
+}
+
+func (cv customValuer) Value() (driver.Value, error) {
+	return cv.value, cv.err
+}
+
+func TestConvertToDriverValue(t *testing.T) {
+	var (
+		intVal           int          = 123
+		int8Val          int8         = 12
+		int16Val         int16        = 1234
+		int32Val         int32        = 12345
+		int64Val         int64        = 123456
+		uintVal          uint         = 123
+		uint8Val         uint8        = 12
+		uint16Val        uint16       = 1234
+		uint32Val        uint32       = 12345
+		uint64Val        uint64       = 1 << 62
+		float32Val       float32      = 12.34
+		float64Val       float64      = 123.456
+		boolVal          bool         = true
+		stringVal        string       = "test"
+		byteSlice        []byte       = []byte("byte slice")
+		ptrToInt         *int         = &intVal
+		nilPtr           *int         = nil
+		valuerSuccess    customValuer = customValuer{value: "valuer value", err: nil}
+		valuerError      customValuer = customValuer{err: errors.New("valuer error")}
+		unsupportedSlice              = []int{1, 2, 3}
+	)
+
+	tests := []struct {
+		name    string
+		value   any
+		want    driver.Value
+		wantErr bool
+	}{
+		{"Int", intVal, int64(intVal), false},
+		{"Int8", int8Val, int64(int8Val), false},
+		{"Int16", int16Val, int64(int16Val), false},
+		{"Int32", int32Val, int64(int32Val), false},
+		{"Int64", int64Val, int64(int64Val), false},
+		{"Uint", uintVal, int64(uintVal), false},
+		{"Uint8", uint8Val, int64(uint8Val), false},
+		{"Uint16", uint16Val, int64(uint16Val), false},
+		{"Uint32", uint32Val, int64(uint32Val), false},
+		{"Uint64", uint64Val, int64(uint64Val), false},
+		{"Float32", float32Val, float64(float32Val), false},
+		{"Float64", float64Val, float64(float64Val), false},
+		{"Bool", boolVal, boolVal, false},
+		{"String", stringVal, stringVal, false},
+		{"ByteSlice", byteSlice, byteSlice, false},
+		{"PointerToInt", ptrToInt, int64(*ptrToInt), false},
+		{"NilPointer", nilPtr, nil, false},
+		{"UnsupportedType", struct{}{}, nil, true},
+		{"Uint64HighBitSet", uint64(1 << 63), nil, true}, // Uint64 with high bit set
+		{"ValuerInterfaceSuccess", valuerSuccess, "valuer value", false},
+		{"ValuerInterfaceError", valuerError, nil, true},
+		{"UnsupportedSliceType", unsupportedSlice, nil, true},
+	}
+
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			got, err := convertToDriverValue(tt.value)
+			if (err != nil) != tt.wantErr {
+				t.Errorf("convertToDriverValue() error = %v, wantErr %v", err, tt.wantErr)
+				return
+			}
+			if !reflect.DeepEqual(got, tt.want) {
+				t.Errorf("convertToDriverValue() = %v, want %v", got, tt.want)
+			}
+		})
+	}
+}
+
+func TestNullableValue_Uint32(t *testing.T) {
+	uint32Val := uint32(12345)
+	nullableUint32 := NewNullable(uint32Val)
+
+	convertedValue, err := nullableUint32.Value()
+
+	if err != nil {
+		t.Fatalf("Nullable[uint32].Value() returned an error: %v", err)
+	}
+
+	if _, ok := convertedValue.(int64); !ok {
+		t.Fatalf("Nullable[uint32].Value() returned a non-int64 type: %T", convertedValue)
+	}
+
+	if int64(uint32Val) != convertedValue.(int64) {
+		t.Errorf("Nullable[uint32].Value() returned %v, want %v", convertedValue, uint32Val)
+	}
+}