snapshot: Do not modify slice of paths

internal/restic/snapshot.go

@@ -30,14 +30,18 @@ type Snapshot struct {
 // NewSnapshot returns an initialized snapshot struct for the current user and
 // time.
 func NewSnapshot(paths []string, tags []string, hostname string, time time.Time) (*Snapshot, error) {
-	for i, path := range paths {
-		if p, err := filepath.Abs(path); err == nil {
-			paths[i] = p
+	absPaths := make([]string, 0, len(paths))
+	for _, path := range paths {
+		p, err := filepath.Abs(path)
+		if err == nil {
+			absPaths = append(absPaths, p)
+		} else {
+			absPaths = append(absPaths, path)
 		}
 	}
 
 	sn := &Snapshot{
-		Paths:    paths,
+		Paths:    absPaths,
 		Time:     time,
 		Tags:     tags,
 		Hostname: hostname,