From 940a3159b5b3bf84ae84c4a1766f6c2359344804 Mon Sep 17 00:00:00 2001
From: Michael Eischer <michael.eischer@fau.de>
Date: Fri, 5 Apr 2024 22:20:14 +0200
Subject: [PATCH] let index.Each() and pack.Size() return error on canceled
 context

This forces a caller to actually check that the function did complete.
---
 cmd/restic/cmd_check.go                 |  6 ++++-
 cmd/restic/cmd_find.go                  | 14 +++++++----
 cmd/restic/cmd_list.go                  |  3 +--
 cmd/restic/cmd_recover.go               |  6 ++---
 cmd/restic/cmd_stats.go                 | 11 +++++----
 cmd/restic/integration_helpers_test.go  |  8 +++----
 internal/checker/checker.go             | 26 ++++++++++++--------
 internal/checker/checker_test.go        |  3 ++-
 internal/checker/testing.go             |  5 +++-
 internal/index/index.go                 |  3 ++-
 internal/index/index_test.go            |  8 +++----
 internal/index/master_index.go          | 16 +++++++------
 internal/index/master_index_test.go     | 12 +++++-----
 internal/pack/pack.go                   |  6 ++---
 internal/repository/prune.go            | 32 ++++++++++++++-----------
 internal/repository/repair_index.go     |  5 +++-
 internal/repository/repair_pack_test.go |  2 +-
 internal/repository/repository.go       |  5 +++-
 internal/repository/repository_test.go  |  4 ++--
 internal/restic/repository.go           |  4 ++--
 20 files changed, 107 insertions(+), 72 deletions(-)

diff --git a/cmd/restic/cmd_check.go b/cmd/restic/cmd_check.go
index 38623c305..c44edae7e 100644
--- a/cmd/restic/cmd_check.go
+++ b/cmd/restic/cmd_check.go
@@ -324,7 +324,11 @@ func runCheck(ctx context.Context, opts CheckOptions, gopts GlobalOptions, args
 	}
 
 	if opts.CheckUnused {
-		for _, id := range chkr.UnusedBlobs(ctx) {
+		unused, err := chkr.UnusedBlobs(ctx)
+		if err != nil {
+			return err
+		}
+		for _, id := range unused {
 			Verbosef("unused blob %v\n", id)
 			errorsFound = true
 		}
diff --git a/cmd/restic/cmd_find.go b/cmd/restic/cmd_find.go
index 77b651c5e..81df0ab98 100644
--- a/cmd/restic/cmd_find.go
+++ b/cmd/restic/cmd_find.go
@@ -439,7 +439,10 @@ func (f *Finder) packsToBlobs(ctx context.Context, packs []string) error {
 
 	if err != errAllPacksFound {
 		// try to resolve unknown pack ids from the index
-		packIDs = f.indexPacksToBlobs(ctx, packIDs)
+		packIDs, err = f.indexPacksToBlobs(ctx, packIDs)
+		if err != nil {
+			return err
+		}
 	}
 
 	if len(packIDs) > 0 {
@@ -456,13 +459,13 @@ func (f *Finder) packsToBlobs(ctx context.Context, packs []string) error {
 	return nil
 }
 
-func (f *Finder) indexPacksToBlobs(ctx context.Context, packIDs map[string]struct{}) map[string]struct{} {
+func (f *Finder) indexPacksToBlobs(ctx context.Context, packIDs map[string]struct{}) (map[string]struct{}, error) {
 	wctx, cancel := context.WithCancel(ctx)
 	defer cancel()
 
 	// remember which packs were found in the index
 	indexPackIDs := make(map[string]struct{})
-	f.repo.Index().Each(wctx, func(pb restic.PackedBlob) {
+	err := f.repo.Index().Each(wctx, func(pb restic.PackedBlob) {
 		idStr := pb.PackID.String()
 		// keep entry in packIDs as Each() returns individual index entries
 		matchingID := false
@@ -481,6 +484,9 @@ func (f *Finder) indexPacksToBlobs(ctx context.Context, packIDs map[string]struc
 			indexPackIDs[idStr] = struct{}{}
 		}
 	})
+	if err != nil {
+		return nil, err
+	}
 
 	for id := range indexPackIDs {
 		delete(packIDs, id)
@@ -493,7 +499,7 @@ func (f *Finder) indexPacksToBlobs(ctx context.Context, packIDs map[string]struc
 		}
 		Warnf("some pack files are missing from the repository, getting their blobs from the repository index: %v\n\n", list)
 	}
-	return packIDs
+	return packIDs, nil
 }
 
 func (f *Finder) findObjectPack(id string, t restic.BlobType) {
diff --git a/cmd/restic/cmd_list.go b/cmd/restic/cmd_list.go
index a3df0c98f..27f59b4ab 100644
--- a/cmd/restic/cmd_list.go
+++ b/cmd/restic/cmd_list.go
@@ -59,10 +59,9 @@ func runList(ctx context.Context, gopts GlobalOptions, args []string) error {
 			if err != nil {
 				return err
 			}
-			idx.Each(ctx, func(blobs restic.PackedBlob) {
+			return idx.Each(ctx, func(blobs restic.PackedBlob) {
 				Printf("%v %v\n", blobs.Type, blobs.ID)
 			})
-			return nil
 		})
 	default:
 		return errors.Fatal("invalid type")
diff --git a/cmd/restic/cmd_recover.go b/cmd/restic/cmd_recover.go
index cac29a60c..debaa4e5b 100644
--- a/cmd/restic/cmd_recover.go
+++ b/cmd/restic/cmd_recover.go
@@ -61,13 +61,13 @@ func runRecover(ctx context.Context, gopts GlobalOptions) error {
 	// tree. If it is not referenced, we have a root tree.
 	trees := make(map[restic.ID]bool)
 
-	repo.Index().Each(ctx, func(blob restic.PackedBlob) {
+	err = repo.Index().Each(ctx, func(blob restic.PackedBlob) {
 		if blob.Type == restic.TreeBlob {
 			trees[blob.Blob.ID] = false
 		}
 	})
-	if ctx.Err() != nil {
-		return ctx.Err()
+	if err != nil {
+		return err
 	}
 
 	Verbosef("load %d trees\n", len(trees))
diff --git a/cmd/restic/cmd_stats.go b/cmd/restic/cmd_stats.go
index 2647d78e5..a7891e5b0 100644
--- a/cmd/restic/cmd_stats.go
+++ b/cmd/restic/cmd_stats.go
@@ -351,7 +351,10 @@ func statsDebug(ctx context.Context, repo restic.Repository) error {
 		Warnf("File Type: %v\n%v\n", t, hist)
 	}
 
-	hist := statsDebugBlobs(ctx, repo)
+	hist, err := statsDebugBlobs(ctx, repo)
+	if err != nil {
+		return err
+	}
 	for _, t := range []restic.BlobType{restic.DataBlob, restic.TreeBlob} {
 		Warnf("Blob Type: %v\n%v\n\n", t, hist[t])
 	}
@@ -369,17 +372,17 @@ func statsDebugFileType(ctx context.Context, repo restic.Lister, tpe restic.File
 	return hist, err
 }
 
-func statsDebugBlobs(ctx context.Context, repo restic.Repository) [restic.NumBlobTypes]*sizeHistogram {
+func statsDebugBlobs(ctx context.Context, repo restic.Repository) ([restic.NumBlobTypes]*sizeHistogram, error) {
 	var hist [restic.NumBlobTypes]*sizeHistogram
 	for i := 0; i < len(hist); i++ {
 		hist[i] = newSizeHistogram(2 * chunker.MaxSize)
 	}
 
-	repo.Index().Each(ctx, func(pb restic.PackedBlob) {
+	err := repo.Index().Each(ctx, func(pb restic.PackedBlob) {
 		hist[pb.Type].Add(uint64(pb.Length))
 	})
 
-	return hist
+	return hist, err
 }
 
 type sizeClass struct {
diff --git a/cmd/restic/integration_helpers_test.go b/cmd/restic/integration_helpers_test.go
index c87e1071e..e7a90dd56 100644
--- a/cmd/restic/integration_helpers_test.go
+++ b/cmd/restic/integration_helpers_test.go
@@ -252,11 +252,11 @@ func listTreePacks(gopts GlobalOptions, t *testing.T) restic.IDSet {
 
 	rtest.OK(t, r.LoadIndex(ctx, nil))
 	treePacks := restic.NewIDSet()
-	r.Index().Each(ctx, func(pb restic.PackedBlob) {
+	rtest.OK(t, r.Index().Each(ctx, func(pb restic.PackedBlob) {
 		if pb.Type == restic.TreeBlob {
 			treePacks.Insert(pb.PackID)
 		}
-	})
+	}))
 
 	return treePacks
 }
@@ -280,11 +280,11 @@ func removePacksExcept(gopts GlobalOptions, t testing.TB, keep restic.IDSet, rem
 	rtest.OK(t, r.LoadIndex(ctx, nil))
 
 	treePacks := restic.NewIDSet()
-	r.Index().Each(ctx, func(pb restic.PackedBlob) {
+	rtest.OK(t, r.Index().Each(ctx, func(pb restic.PackedBlob) {
 		if pb.Type == restic.TreeBlob {
 			treePacks.Insert(pb.PackID)
 		}
-	})
+	}))
 
 	// remove all packs containing data blobs
 	rtest.OK(t, r.List(ctx, restic.PackFile, func(id restic.ID, size int64) error {
diff --git a/internal/checker/checker.go b/internal/checker/checker.go
index 28f55ce3a..1057341bc 100644
--- a/internal/checker/checker.go
+++ b/internal/checker/checker.go
@@ -106,9 +106,9 @@ func (c *Checker) LoadSnapshots(ctx context.Context) error {
 	return err
 }
 
-func computePackTypes(ctx context.Context, idx restic.MasterIndex) map[restic.ID]restic.BlobType {
+func computePackTypes(ctx context.Context, idx restic.MasterIndex) (map[restic.ID]restic.BlobType, error) {
 	packs := make(map[restic.ID]restic.BlobType)
-	idx.Each(ctx, func(pb restic.PackedBlob) {
+	err := idx.Each(ctx, func(pb restic.PackedBlob) {
 		tpe, exists := packs[pb.PackID]
 		if exists {
 			if pb.Type != tpe {
@@ -119,7 +119,7 @@ func computePackTypes(ctx context.Context, idx restic.MasterIndex) map[restic.ID
 		}
 		packs[pb.PackID] = tpe
 	})
-	return packs
+	return packs, err
 }
 
 // LoadIndex loads all index files.
@@ -169,7 +169,7 @@ func (c *Checker) LoadIndex(ctx context.Context, p *progress.Counter) (hints []e
 
 		debug.Log("process blobs")
 		cnt := 0
-		index.Each(ctx, func(blob restic.PackedBlob) {
+		err = index.Each(ctx, func(blob restic.PackedBlob) {
 			cnt++
 
 			if _, ok := packToIndex[blob.PackID]; !ok {
@@ -179,7 +179,7 @@ func (c *Checker) LoadIndex(ctx context.Context, p *progress.Counter) (hints []e
 		})
 
 		debug.Log("%d blobs processed", cnt)
-		return nil
+		return err
 	})
 	if err != nil {
 		errs = append(errs, err)
@@ -193,8 +193,14 @@ func (c *Checker) LoadIndex(ctx context.Context, p *progress.Counter) (hints []e
 	}
 
 	// compute pack size using index entries
-	c.packs = pack.Size(ctx, c.masterIndex, false)
-	packTypes := computePackTypes(ctx, c.masterIndex)
+	c.packs, err = pack.Size(ctx, c.masterIndex, false)
+	if err != nil {
+		return hints, append(errs, err)
+	}
+	packTypes, err := computePackTypes(ctx, c.masterIndex)
+	if err != nil {
+		return hints, append(errs, err)
+	}
 
 	debug.Log("checking for duplicate packs")
 	for packID := range c.packs {
@@ -484,7 +490,7 @@ func (c *Checker) checkTree(id restic.ID, tree *restic.Tree) (errs []error) {
 }
 
 // UnusedBlobs returns all blobs that have never been referenced.
-func (c *Checker) UnusedBlobs(ctx context.Context) (blobs restic.BlobHandles) {
+func (c *Checker) UnusedBlobs(ctx context.Context) (blobs restic.BlobHandles, err error) {
 	if !c.trackUnused {
 		panic("only works when tracking blob references")
 	}
@@ -495,7 +501,7 @@ func (c *Checker) UnusedBlobs(ctx context.Context) (blobs restic.BlobHandles) {
 	ctx, cancel := context.WithCancel(ctx)
 	defer cancel()
 
-	c.repo.Index().Each(ctx, func(blob restic.PackedBlob) {
+	err = c.repo.Index().Each(ctx, func(blob restic.PackedBlob) {
 		h := restic.BlobHandle{ID: blob.ID, Type: blob.Type}
 		if !c.blobRefs.M.Has(h) {
 			debug.Log("blob %v not referenced", h)
@@ -503,7 +509,7 @@ func (c *Checker) UnusedBlobs(ctx context.Context) (blobs restic.BlobHandles) {
 		}
 	})
 
-	return blobs
+	return blobs, err
 }
 
 // CountPacks returns the number of packs in the repository.
diff --git a/internal/checker/checker_test.go b/internal/checker/checker_test.go
index b0fa4e3e3..9746e9f5d 100644
--- a/internal/checker/checker_test.go
+++ b/internal/checker/checker_test.go
@@ -180,7 +180,8 @@ func TestUnreferencedBlobs(t *testing.T) {
 	test.OKs(t, checkPacks(chkr))
 	test.OKs(t, checkStruct(chkr))
 
-	blobs := chkr.UnusedBlobs(context.TODO())
+	blobs, err := chkr.UnusedBlobs(context.TODO())
+	test.OK(t, err)
 	sort.Sort(blobs)
 
 	test.Equals(t, unusedBlobsBySnapshot, blobs)
diff --git a/internal/checker/testing.go b/internal/checker/testing.go
index 9e949af02..d0014398f 100644
--- a/internal/checker/testing.go
+++ b/internal/checker/testing.go
@@ -43,7 +43,10 @@ func TestCheckRepo(t testing.TB, repo restic.Repository, skipStructure bool) {
 		}
 
 		// unused blobs
-		blobs := chkr.UnusedBlobs(context.TODO())
+		blobs, err := chkr.UnusedBlobs(context.TODO())
+		if err != nil {
+			t.Error(err)
+		}
 		if len(blobs) > 0 {
 			t.Errorf("unused blobs found: %v", blobs)
 		}
diff --git a/internal/index/index.go b/internal/index/index.go
index 73128f7bb..1c20fe38d 100644
--- a/internal/index/index.go
+++ b/internal/index/index.go
@@ -218,7 +218,7 @@ func (idx *Index) AddToSupersedes(ids ...restic.ID) error {
 
 // Each passes all blobs known to the index to the callback fn. This blocks any
 // modification of the index.
-func (idx *Index) Each(ctx context.Context, fn func(restic.PackedBlob)) {
+func (idx *Index) Each(ctx context.Context, fn func(restic.PackedBlob)) error {
 	idx.m.Lock()
 	defer idx.m.Unlock()
 
@@ -232,6 +232,7 @@ func (idx *Index) Each(ctx context.Context, fn func(restic.PackedBlob)) {
 			return true
 		})
 	}
+	return ctx.Err()
 }
 
 type EachByPackResult struct {
diff --git a/internal/index/index_test.go b/internal/index/index_test.go
index 78e4800ca..bafd95c48 100644
--- a/internal/index/index_test.go
+++ b/internal/index/index_test.go
@@ -339,7 +339,7 @@ func TestIndexUnserialize(t *testing.T) {
 
 		rtest.Equals(t, oldIdx, idx.Supersedes())
 
-		blobs := listPack(idx, exampleLookupTest.packID)
+		blobs := listPack(t, idx, exampleLookupTest.packID)
 		if len(blobs) != len(exampleLookupTest.blobs) {
 			t.Fatalf("expected %d blobs in pack, got %d", len(exampleLookupTest.blobs), len(blobs))
 		}
@@ -356,12 +356,12 @@ func TestIndexUnserialize(t *testing.T) {
 	}
 }
 
-func listPack(idx *index.Index, id restic.ID) (pbs []restic.PackedBlob) {
-	idx.Each(context.TODO(), func(pb restic.PackedBlob) {
+func listPack(t testing.TB, idx *index.Index, id restic.ID) (pbs []restic.PackedBlob) {
+	rtest.OK(t, idx.Each(context.TODO(), func(pb restic.PackedBlob) {
 		if pb.PackID.Equal(id) {
 			pbs = append(pbs, pb)
 		}
-	})
+	}))
 	return pbs
 }
 
diff --git a/internal/index/master_index.go b/internal/index/master_index.go
index 9833f9a55..d99a3434d 100644
--- a/internal/index/master_index.go
+++ b/internal/index/master_index.go
@@ -223,13 +223,16 @@ func (mi *MasterIndex) finalizeFullIndexes() []*Index {
 
 // Each runs fn on all blobs known to the index. When the context is cancelled,
 // the index iteration return immediately. This blocks any modification of the index.
-func (mi *MasterIndex) Each(ctx context.Context, fn func(restic.PackedBlob)) {
+func (mi *MasterIndex) Each(ctx context.Context, fn func(restic.PackedBlob)) error {
 	mi.idxMutex.RLock()
 	defer mi.idxMutex.RUnlock()
 
 	for _, idx := range mi.idx {
-		idx.Each(ctx, fn)
+		if err := idx.Each(ctx, fn); err != nil {
+			return err
+		}
 	}
+	return nil
 }
 
 // MergeFinalIndexes merges all final indexes together.
@@ -429,10 +432,6 @@ func (mi *MasterIndex) ListPacks(ctx context.Context, packs restic.IDSet) <-chan
 		defer close(out)
 		// only resort a part of the index to keep the memory overhead bounded
 		for i := byte(0); i < 16; i++ {
-			if ctx.Err() != nil {
-				return
-			}
-
 			packBlob := make(map[restic.ID][]restic.Blob)
 			for pack := range packs {
 				if pack[0]&0xf == i {
@@ -442,11 +441,14 @@ func (mi *MasterIndex) ListPacks(ctx context.Context, packs restic.IDSet) <-chan
 			if len(packBlob) == 0 {
 				continue
 			}
-			mi.Each(ctx, func(pb restic.PackedBlob) {
+			err := mi.Each(ctx, func(pb restic.PackedBlob) {
 				if packs.Has(pb.PackID) && pb.PackID[0]&0xf == i {
 					packBlob[pb.PackID] = append(packBlob[pb.PackID], pb.Blob)
 				}
 			})
+			if err != nil {
+				return
+			}
 
 			// pass on packs
 			for packID, pbs := range packBlob {
diff --git a/internal/index/master_index_test.go b/internal/index/master_index_test.go
index dcf6a94f6..fe0364c61 100644
--- a/internal/index/master_index_test.go
+++ b/internal/index/master_index_test.go
@@ -166,9 +166,9 @@ func TestMasterMergeFinalIndexes(t *testing.T) {
 	rtest.Equals(t, 1, idxCount)
 
 	blobCount := 0
-	mIdx.Each(context.TODO(), func(pb restic.PackedBlob) {
+	rtest.OK(t, mIdx.Each(context.TODO(), func(pb restic.PackedBlob) {
 		blobCount++
-	})
+	}))
 	rtest.Equals(t, 2, blobCount)
 
 	blobs := mIdx.Lookup(bhInIdx1)
@@ -198,9 +198,9 @@ func TestMasterMergeFinalIndexes(t *testing.T) {
 	rtest.Equals(t, []restic.PackedBlob{blob2}, blobs)
 
 	blobCount = 0
-	mIdx.Each(context.TODO(), func(pb restic.PackedBlob) {
+	rtest.OK(t, mIdx.Each(context.TODO(), func(pb restic.PackedBlob) {
 		blobCount++
-	})
+	}))
 	rtest.Equals(t, 2, blobCount)
 }
 
@@ -319,9 +319,9 @@ func BenchmarkMasterIndexEach(b *testing.B) {
 
 	for i := 0; i < b.N; i++ {
 		entries := 0
-		mIdx.Each(context.TODO(), func(pb restic.PackedBlob) {
+		rtest.OK(b, mIdx.Each(context.TODO(), func(pb restic.PackedBlob) {
 			entries++
-		})
+		}))
 	}
 }
 
diff --git a/internal/pack/pack.go b/internal/pack/pack.go
index cd118ab03..53631a6fb 100644
--- a/internal/pack/pack.go
+++ b/internal/pack/pack.go
@@ -389,10 +389,10 @@ func CalculateHeaderSize(blobs []restic.Blob) int {
 // If onlyHdr is set to true, only the size of the header is returned
 // Note that this function only gives correct sizes, if there are no
 // duplicates in the index.
-func Size(ctx context.Context, mi restic.MasterIndex, onlyHdr bool) map[restic.ID]int64 {
+func Size(ctx context.Context, mi restic.MasterIndex, onlyHdr bool) (map[restic.ID]int64, error) {
 	packSize := make(map[restic.ID]int64)
 
-	mi.Each(ctx, func(blob restic.PackedBlob) {
+	err := mi.Each(ctx, func(blob restic.PackedBlob) {
 		size, ok := packSize[blob.PackID]
 		if !ok {
 			size = headerSize
@@ -403,5 +403,5 @@ func Size(ctx context.Context, mi restic.MasterIndex, onlyHdr bool) map[restic.I
 		packSize[blob.PackID] = size + int64(CalculateEntrySize(blob.Blob))
 	})
 
-	return packSize
+	return packSize, err
 }
diff --git a/internal/repository/prune.go b/internal/repository/prune.go
index 39eb30317..77811e321 100644
--- a/internal/repository/prune.go
+++ b/internal/repository/prune.go
@@ -124,14 +124,14 @@ func PlanPrune(ctx context.Context, opts PruneOptions, repo restic.Repository, g
 		blobCount := keepBlobs.Len()
 		// when repacking, we do not want to keep blobs which are
 		// already contained in kept packs, so delete them from keepBlobs
-		repo.Index().Each(ctx, func(blob restic.PackedBlob) {
+		err := repo.Index().Each(ctx, func(blob restic.PackedBlob) {
 			if plan.removePacks.Has(blob.PackID) || plan.repackPacks.Has(blob.PackID) {
 				return
 			}
 			keepBlobs.Delete(blob.BlobHandle)
 		})
-		if ctx.Err() != nil {
-			return nil, ctx.Err()
+		if err != nil {
+			return nil, err
 		}
 
 		if keepBlobs.Len() < blobCount/2 {
@@ -155,7 +155,7 @@ func packInfoFromIndex(ctx context.Context, idx restic.MasterIndex, usedBlobs re
 	// iterate over all blobs in index to find out which blobs are duplicates
 	// The counter in usedBlobs describes how many instances of the blob exist in the repository index
 	// Thus 0 == blob is missing, 1 == blob exists once, >= 2 == duplicates exist
-	idx.Each(ctx, func(blob restic.PackedBlob) {
+	err := idx.Each(ctx, func(blob restic.PackedBlob) {
 		bh := blob.BlobHandle
 		count, ok := usedBlobs[bh]
 		if ok {
@@ -169,8 +169,8 @@ func packInfoFromIndex(ctx context.Context, idx restic.MasterIndex, usedBlobs re
 			usedBlobs[bh] = count
 		}
 	})
-	if ctx.Err() != nil {
-		return nil, nil, ctx.Err()
+	if err != nil {
+		return nil, nil, err
 	}
 
 	// Check if all used blobs have been found in index
@@ -194,14 +194,18 @@ func packInfoFromIndex(ctx context.Context, idx restic.MasterIndex, usedBlobs re
 	indexPack := make(map[restic.ID]packInfo)
 
 	// save computed pack header size
-	for pid, hdrSize := range pack.Size(ctx, idx, true) {
+	sz, err := pack.Size(ctx, idx, true)
+	if err != nil {
+		return nil, nil, err
+	}
+	for pid, hdrSize := range sz {
 		// initialize tpe with NumBlobTypes to indicate it's not set
 		indexPack[pid] = packInfo{tpe: restic.NumBlobTypes, usedSize: uint64(hdrSize)}
 	}
 
 	hasDuplicates := false
 	// iterate over all blobs in index to generate packInfo
-	idx.Each(ctx, func(blob restic.PackedBlob) {
+	err = idx.Each(ctx, func(blob restic.PackedBlob) {
 		ip := indexPack[blob.PackID]
 
 		// Set blob type if not yet set
@@ -246,8 +250,8 @@ func packInfoFromIndex(ctx context.Context, idx restic.MasterIndex, usedBlobs re
 		// update indexPack
 		indexPack[blob.PackID] = ip
 	})
-	if ctx.Err() != nil {
-		return nil, nil, ctx.Err()
+	if err != nil {
+		return nil, nil, err
 	}
 
 	// if duplicate blobs exist, those will be set to either "used" or "unused":
@@ -256,7 +260,7 @@ func packInfoFromIndex(ctx context.Context, idx restic.MasterIndex, usedBlobs re
 	// - if there are no used blobs in a pack, possibly mark duplicates as "unused"
 	if hasDuplicates {
 		// iterate again over all blobs in index (this is pretty cheap, all in-mem)
-		idx.Each(ctx, func(blob restic.PackedBlob) {
+		err = idx.Each(ctx, func(blob restic.PackedBlob) {
 			bh := blob.BlobHandle
 			count, ok := usedBlobs[bh]
 			// skip non-duplicate, aka. normal blobs
@@ -294,9 +298,9 @@ func packInfoFromIndex(ctx context.Context, idx restic.MasterIndex, usedBlobs re
 			// update indexPack
 			indexPack[blob.PackID] = ip
 		})
-	}
-	if ctx.Err() != nil {
-		return nil, nil, ctx.Err()
+		if err != nil {
+			return nil, nil, err
+		}
 	}
 
 	// Sanity check. If no duplicates exist, all blobs have value 1. After handling
diff --git a/internal/repository/repair_index.go b/internal/repository/repair_index.go
index 63e104132..a6e732b44 100644
--- a/internal/repository/repair_index.go
+++ b/internal/repository/repair_index.go
@@ -54,7 +54,10 @@ func RepairIndex(ctx context.Context, repo *Repository, opts RepairIndexOptions,
 		if err != nil {
 			return err
 		}
-		packSizeFromIndex = pack.Size(ctx, repo.Index(), false)
+		packSizeFromIndex, err = pack.Size(ctx, repo.Index(), false)
+		if err != nil {
+			return err
+		}
 	}
 
 	printer.P("getting pack files to read...\n")
diff --git a/internal/repository/repair_pack_test.go b/internal/repository/repair_pack_test.go
index c5cdf5ed5..078017d21 100644
--- a/internal/repository/repair_pack_test.go
+++ b/internal/repository/repair_pack_test.go
@@ -17,7 +17,7 @@ import (
 
 func listBlobs(repo restic.Repository) restic.BlobSet {
 	blobs := restic.NewBlobSet()
-	repo.Index().Each(context.TODO(), func(pb restic.PackedBlob) {
+	_ = repo.Index().Each(context.TODO(), func(pb restic.PackedBlob) {
 		blobs.Insert(pb.BlobHandle)
 	})
 	return blobs
diff --git a/internal/repository/repository.go b/internal/repository/repository.go
index a43971266..cac1551c4 100644
--- a/internal/repository/repository.go
+++ b/internal/repository/repository.go
@@ -704,11 +704,14 @@ func (r *Repository) LoadIndex(ctx context.Context, p *progress.Counter) error {
 		defer cancel()
 
 		invalidIndex := false
-		r.idx.Each(ctx, func(blob restic.PackedBlob) {
+		err := r.idx.Each(ctx, func(blob restic.PackedBlob) {
 			if blob.IsCompressed() {
 				invalidIndex = true
 			}
 		})
+		if err != nil {
+			return err
+		}
 		if invalidIndex {
 			return errors.New("index uses feature not supported by repository version 1")
 		}
diff --git a/internal/repository/repository_test.go b/internal/repository/repository_test.go
index b013c4823..48a56a1fd 100644
--- a/internal/repository/repository_test.go
+++ b/internal/repository/repository_test.go
@@ -370,13 +370,13 @@ func testRepositoryIncrementalIndex(t *testing.T, version uint) {
 		idx, err := loadIndex(context.TODO(), repo, id)
 		rtest.OK(t, err)
 
-		idx.Each(context.TODO(), func(pb restic.PackedBlob) {
+		rtest.OK(t, idx.Each(context.TODO(), func(pb restic.PackedBlob) {
 			if _, ok := packEntries[pb.PackID]; !ok {
 				packEntries[pb.PackID] = make(map[restic.ID]struct{})
 			}
 
 			packEntries[pb.PackID][id] = struct{}{}
-		})
+		}))
 		return nil
 	})
 	if err != nil {
diff --git a/internal/restic/repository.go b/internal/restic/repository.go
index 89c54ffbb..7a3389e00 100644
--- a/internal/restic/repository.go
+++ b/internal/restic/repository.go
@@ -103,8 +103,8 @@ type MasterIndex interface {
 	Lookup(BlobHandle) []PackedBlob
 
 	// Each runs fn on all blobs known to the index. When the context is cancelled,
-	// the index iteration return immediately. This blocks any modification of the index.
-	Each(ctx context.Context, fn func(PackedBlob))
+	// the index iteration returns immediately with ctx.Err(). This blocks any modification of the index.
+	Each(ctx context.Context, fn func(PackedBlob)) error
 	ListPacks(ctx context.Context, packs IDSet) <-chan PackBlobs
 
 	Save(ctx context.Context, repo Repository, excludePacks IDSet, extraObsolete IDs, opts MasterIndexSaveOpts) error