restic check and restic repair packs: treat missing packfiles the same as damaged and truncated packfiles (#21845)

Co-authored-by: Michael Eischer <michael.eischer@fau.de>

internal/repository/checker.go

@@ -57,6 +57,7 @@ type ErrPackMetadata struct {
 	ID        restic.ID
 	Orphaned  bool
 	Truncated bool
+	Missing   bool
 	Err       error
 }
 
@@ -218,7 +219,7 @@ func (c *Checker) Packs(ctx context.Context, errChan chan<- error) {
 			select {
 			case <-ctx.Done():
 				return
-			case errChan <- &ErrPackMetadata{ID: id, Err: errors.New("does not exist")}:
+			case errChan <- &ErrPackMetadata{ID: id, Missing: true, Err: errors.New("does not exist")}:
 			}
 			continue
 		}

internal/repository/repair_pack.go

@@ -65,7 +65,13 @@ func RepairPacks(ctx context.Context, repo *Repository, ids restic.IDSet, printe
 	printer.P("removing salvaged pack files")
 	// if we fail to delete the damaged pack files, then prune will remove them later on
 	bar = printer.NewCounter("files deleted")
-	_ = restic.ParallelRemove(ctx, &internalRepository{repo}, ids, restic.PackFile, nil, bar)
+	_ = restic.ParallelRemove(ctx, &internalRepository{repo}, ids, restic.PackFile, func(id restic.ID, err error) error {
+		// only log errors while deleting pack files
+		if err != nil {
+			printer.E("failed to delete pack file %v: %v", id, err)
+		}
+		return nil
+	}, bar)
 	bar.Done()
 
 	return nil