From bdd085e9f163449d6c14d3a2f1475f0e5241be56 Mon Sep 17 00:00:00 2001
From: Alexander Neumann <alexander@bumpern.de>
Date: Mon, 1 Aug 2016 18:45:03 +0200
Subject: [PATCH] Prevent loops when finding used blobs

---
 src/restic/find.go | 13 ++++++++++---
 1 file changed, 10 insertions(+), 3 deletions(-)

diff --git a/src/restic/find.go b/src/restic/find.go
index 7d7a8698a..974ebf673 100644
--- a/src/restic/find.go
+++ b/src/restic/find.go
@@ -6,7 +6,7 @@ import (
 )
 
 //  FindUsedBlobs traverse the tree ID and adds all seen blobs to blobs.
-func findUsedBlobs(repo *repository.Repository, treeID backend.ID, blobs backend.IDSet) error {
+func findUsedBlobs(repo *repository.Repository, treeID backend.ID, blobs backend.IDSet, seen backend.IDSet) error {
 	blobs.Insert(treeID)
 
 	tree, err := LoadTree(repo, treeID)
@@ -21,7 +21,14 @@ func findUsedBlobs(repo *repository.Repository, treeID backend.ID, blobs backend
 				blobs.Insert(blob)
 			}
 		case "dir":
-			err := findUsedBlobs(repo, *node.Subtree, blobs)
+			subtreeID := *node.Subtree
+			if seen.Has(subtreeID) {
+				continue
+			}
+
+			seen.Insert(subtreeID)
+
+			err := findUsedBlobs(repo, subtreeID, blobs, seen)
 			if err != nil {
 				return err
 			}
@@ -35,5 +42,5 @@ func findUsedBlobs(repo *repository.Repository, treeID backend.ID, blobs backend
 // encountered.
 func FindUsedBlobs(repo *repository.Repository, treeID backend.ID) (blobs backend.IDSet, err error) {
 	blobs = backend.NewIDSet()
-	return blobs, findUsedBlobs(repo, treeID, blobs)
+	return blobs, findUsedBlobs(repo, treeID, blobs, backend.NewIDSet())
 }