Fix incremental backup

Copying blobs (for unchanged files and subtrees) from old BlobList to
new BlobList was missing

archiver.go

@@ -32,7 +32,7 @@ type Archiver struct {
 	p *Progress
 }
 
-func NewArchiver(s Server, p *Progress) (*Archiver, error) {
+func NewArchiver(s Server, bl *BlobList, p *Progress) (*Archiver, error) {
 	var err error
 	arch := &Archiver{
 		s:         s,
@@ -56,6 +56,9 @@ func NewArchiver(s Server, p *Progress) (*Archiver, error) {
 	arch.Filter = func(string, os.FileInfo) bool { return true }
 
 	arch.bl = NewBlobList()
+	if bl != nil {
+		arch.bl.Merge(bl)
+	}
 	arch.ch = NewContentHandler(s)
 
 	// load all blobs from all snapshots

cmd/restic/cmd_backup.go

@@ -120,6 +120,7 @@ func (cmd CmdBackup) Execute(args []string) error {
 		return err
 	}
 
+	var bl *restic.BlobList
 	if parentSnapshotID != nil {
 		fmt.Printf("load old snapshot\n")
 		ch := restic.NewContentHandler(s)
@@ -133,7 +134,11 @@ func (cmd CmdBackup) Execute(args []string) error {
 			return err
 		}
 
-		newTree.CopyFrom(oldTree)
+		bl = restic.NewBlobList()
+		err = newTree.CopyFrom(bl, oldTree, ch.BlobList())
+		if err != nil {
+			return err
+		}
 	}
 
 	archiveProgress := restic.NewProgress(time.Second)
@@ -170,7 +175,7 @@ func (cmd CmdBackup) Execute(args []string) error {
 		}
 	}
 
-	arch, err := restic.NewArchiver(s, archiveProgress)
+	arch, err := restic.NewArchiver(s, bl, archiveProgress)
 	if err != nil {
 		fmt.Fprintf(os.Stderr, "err: %v\n", err)
 	}

tree.go

@@ -120,7 +120,7 @@ func LoadTreeRecursive(path string, ch *ContentHandler, id backend.ID) (Tree, er
 }
 
 // CopyFrom recursively copies all content from other to t.
-func (t Tree) CopyFrom(other Tree) {
+func (t Tree) CopyFrom(bl *BlobList, other Tree, otherBl *BlobList) error {
 	for _, node := range t {
 		// only process files and dirs
 		if node.Type != "file" && node.Type != "dir" {
@@ -140,18 +140,41 @@ func (t Tree) CopyFrom(other Tree) {
 			if node.SameContent(oldNode) {
 				// copy Content
 				node.Content = oldNode.Content
+
+				// copy storage IDs
+				for _, id := range node.Content {
+					blob, err := otherBl.Find(Blob{ID: id})
+					if err != nil {
+						return err
+					}
+
+					bl.Insert(blob)
+				}
 			}
 		} else {
 			// fill in all subtrees from old subtree
-			node.tree.CopyFrom(*oldNode.tree)
+			err := node.tree.CopyFrom(bl, *oldNode.tree, otherBl)
+			if err != nil {
+				return err
+			}
 
 			// check if tree has changed
 			if node.tree.Equals(*oldNode.tree) {
 				// if nothing has changed, copy subtree ID
 				node.Subtree = oldNode.Subtree
+
+				// and store blob in bloblist
+				blob, err := otherBl.Find(Blob{ID: oldNode.Subtree})
+				if err != nil {
+					return err
+				}
+
+				bl.Insert(blob)
 			}
 		}
 	}
+
+	return nil
 }
 
 // Equals returns true if t and other have exactly the same nodes.