Reuse byte slices.

driver/driver.go

@@ -157,11 +157,10 @@ func (r rows) Columns() []string {
 
 func (r rows) Next(dest []driver.Value) error {
 	if !r.s.Step() {
-		err := r.s.Err()
-		if err == nil {
-			return io.EOF
+		if err := r.s.Err(); err != nil {
+			return err
 		}
-		return err
+		return io.EOF
 	}
 
 	for i := range dest {
@@ -173,9 +172,14 @@ func (r rows) Next(dest []driver.Value) error {
 		case sqlite3.TEXT:
 			dest[i] = maybeDate(r.s.ColumnText(i))
 		case sqlite3.BLOB:
-			dest[i] = r.s.ColumnBlob(i, nil)
+			buf, _ := dest[i].([]byte)
+			dest[i] = r.s.ColumnBlob(i, buf)
 		case sqlite3.NULL:
-			dest[i] = nil
+			if buf, ok := dest[i].([]byte); ok {
+				dest[i] = buf[0:0]
+			} else {
+				dest[i] = nil
+			}
 		default:
 			panic(assertErr)
 		}

driver/example_test.go

@@ -106,19 +106,19 @@ func albumsByArtist(name string) ([]Album, error) {
 
 	rows, err := db.Query("SELECT * FROM album WHERE artist = ?", name)
 	if err != nil {
-		return nil, fmt.Errorf("albumsByArtist %q: %v", name, err)
+		return nil, fmt.Errorf("albumsByArtist %q: %w", name, err)
 	}
 	defer rows.Close()
 	// Loop through rows, using Scan to assign column data to struct fields.
 	for rows.Next() {
 		var alb Album
 		if err := rows.Scan(&alb.ID, &alb.Title, &alb.Artist, &alb.Price); err != nil {
-			return nil, fmt.Errorf("albumsByArtist %q: %v", name, err)
+			return nil, fmt.Errorf("albumsByArtist %q: %w", name, err)
 		}
 		albums = append(albums, alb)
 	}
 	if err := rows.Err(); err != nil {
-		return nil, fmt.Errorf("albumsByArtist %q: %v", name, err)
+		return nil, fmt.Errorf("albumsByArtist %q: %w", name, err)
 	}
 	return albums, nil
 }
@@ -133,7 +133,7 @@ func albumByID(id int64) (Album, error) {
 		if err == sql.ErrNoRows {
 			return alb, fmt.Errorf("albumsById %d: no such album", id)
 		}
-		return alb, fmt.Errorf("albumsById %d: %v", id, err)
+		return alb, fmt.Errorf("albumsById %d: %w", id, err)
 	}
 	return alb, nil
 }
@@ -143,11 +143,11 @@ func albumByID(id int64) (Album, error) {
 func addAlbum(alb Album) (int64, error) {
 	result, err := db.Exec("INSERT INTO album (title, artist, price) VALUES (?, ?, ?)", alb.Title, alb.Artist, alb.Price)
 	if err != nil {
-		return 0, fmt.Errorf("addAlbum: %v", err)
+		return 0, fmt.Errorf("addAlbum: %w", err)
 	}
 	id, err := result.LastInsertId()
 	if err != nil {
-		return 0, fmt.Errorf("addAlbum: %v", err)
+		return 0, fmt.Errorf("addAlbum: %w", err)
 	}
 	return id, nil
 }