feat: no ErrNoRows when scan nil struct ptr

Author: CyJaySong

internal/dbtest/db_test.go

@@ -262,6 +262,7 @@ func TestDB(t *testing.T) {
 		{testSelectMap},
 		{testSelectMapSlice},
 		{testSelectStruct},
+		{testSelectStructNilPtr},
 		{testSelectNestedStructValue},
 		{testSelectNestedStructPtr},
 		{testSelectStructSlice},
@@ -444,6 +445,51 @@ func testSelectStruct(t *testing.T, db *bun.DB) {
 	require.Contains(t, err.Error(), "Model does not have column")
 }
 
+func testSelectStructNilPtr(t *testing.T, db *bun.DB) {
+	type Model struct {
+		Num int
+		Str string
+	}
+
+	// Scan a row into a nil **Model: the inner pointer should be allocated and populated.
+	var model *Model
+	err := db.NewSelect().
+		ColumnExpr("10 AS num, 'hello' AS str").
+		Scan(ctx, &model)
+	require.NoError(t, err)
+	require.NotNil(t, model)
+	require.Equal(t, 10, model.Num)
+	require.Equal(t, "hello", model.Str)
+
+	// No rows + nil **Model: should NOT return ErrNoRows; inner pointer stays nil.
+	var empty *Model
+	err = db.NewSelect().
+		TableExpr("(SELECT 42 AS num) AS t").
+		Where("1 = 2").
+		Scan(ctx, &empty)
+	require.NoError(t, err)
+	require.Nil(t, empty)
+
+	// Regression: a non-nil *Model (existing behaviour) must still return ErrNoRows.
+	nonNil := new(Model)
+	err = db.NewSelect().
+		TableExpr("(SELECT 42 AS num) AS t").
+		Where("1 = 2").
+		Scan(ctx, nonNil)
+	require.Equal(t, sql.ErrNoRows, err)
+
+	// Scan a row into a non-nil **Model: the existing inner pointer is reused.
+	existing := &Model{}
+	preserved := existing
+	err = db.NewSelect().
+		ColumnExpr("7 AS num, 'world' AS str").
+		Scan(ctx, &existing)
+	require.NoError(t, err)
+	require.Same(t, preserved, existing)
+	require.Equal(t, 7, existing.Num)
+	require.Equal(t, "world", existing.Str)
+}
+
 func testSelectNestedStructValue(t *testing.T, db *bun.DB) {
 	type Model struct {
 		Num int

model.go

@@ -124,6 +124,10 @@ func _newModel(db *DB, dest any, scan bool) (Model, error) {
 		return newMapModel(db, mapPtr), nil
 	case reflect.Struct:
 		return newStructTableModelValue(db, dest, v), nil
+	case reflect.Pointer:
+		if v.Type().Elem().Kind() == reflect.Struct {
+			return newStructTableModelValue(db, dest, v), nil
+		}
 	case reflect.Slice:
 		switch elemType := sliceElemType(v); elemType.Kind() {
 		case reflect.Struct:
@@ -200,8 +204,7 @@ func validMap(typ reflect.Type) error {
 
 func isSingleRowModel(m Model) bool {
 	switch m.(type) {
-	case *mapModel,
-		*structTableModel,
+	case *structTableModel,
 		*scanModel:
 		return true
 	default:

query_base.go

@@ -630,6 +630,9 @@ func (q *baseQuery) _scan(
 	}
 
 	if numRow == 0 && hasDest && isSingleRowModel(model) {
+		if nm, ok := model.(*structTableModel); ok && nm.isNil() {
+			return driver.RowsAffected(numRow), nil
+		}
 		return nil, sql.ErrNoRows
 	}
 	return driver.RowsAffected(numRow), nil