repository: Push all usage of errors.Fatal out of the package

As the `Fatal` error type only includes a string, it becomes impossible
to inspect the contained error. This is for a example a problem for the
fuse implementation, which must be able to detect context.Canceled
errors.

Co-authored-by: greatroar <61184462+greatroar@users.noreply.github.com>

internal/repository/key.go

@@ -21,7 +21,7 @@ var (
 	ErrNoKeyFound = errors.New("wrong password or no key found")
 
 	// ErrMaxKeysReached is returned when the maximum number of keys was checked and no key could be found.
-	ErrMaxKeysReached = errors.Fatal("maximum number of keys reached")
+	ErrMaxKeysReached = errors.New("maximum number of keys reached")
 )
 
 // Key represents an encrypted master key for a repository.

internal/repository/repack.go

@@ -29,7 +29,7 @@ func Repack(ctx context.Context, repo restic.Repository, dstRepo restic.Reposito
 	debug.Log("repacking %d packs while keeping %d blobs", len(packs), keepBlobs.Len())
 
 	if repo == dstRepo && dstRepo.Connections() < 2 {
-		return nil, errors.Fatal("repack step requires a backend connection limit of at least two")
+		return nil, errors.New("repack step requires a backend connection limit of at least two")
 	}
 
 	wg, wgCtx := errgroup.WithContext(ctx)

internal/repository/repository.go

@@ -110,16 +110,16 @@ func (c *CompressionMode) Type() string {
 // New returns a new repository with backend be.
 func New(be restic.Backend, opts Options) (*Repository, error) {
 	if opts.Compression == CompressionInvalid {
-		return nil, errors.Fatalf("invalid compression mode")
+		return nil, errors.New("invalid compression mode")
 	}
 
 	if opts.PackSize == 0 {
 		opts.PackSize = DefaultPackSize
 	}
 	if opts.PackSize > MaxPackSize {
-		return nil, errors.Fatalf("pack size larger than limit of %v MiB", MaxPackSize/1024/1024)
+		return nil, fmt.Errorf("pack size larger than limit of %v MiB", MaxPackSize/1024/1024)
 	} else if opts.PackSize < MinPackSize {
-		return nil, errors.Fatalf("pack size smaller than minimum of %v MiB", MinPackSize/1024/1024)
+		return nil, fmt.Errorf("pack size smaller than minimum of %v MiB", MinPackSize/1024/1024)
 	}
 
 	repo := &Repository{
@@ -593,7 +593,7 @@ func (r *Repository) LoadIndex(ctx context.Context) error {
 	})
 
 	if err != nil {
-		return errors.Fatal(err.Error())
+		return err
 	}
 
 	err = r.idx.MergeFinalIndexes()
@@ -613,7 +613,7 @@ func (r *Repository) LoadIndex(ctx context.Context) error {
 			}
 		})
 		if invalidIndex {
-			return errors.Fatal("index uses feature not supported by repository version 1")
+			return errors.New("index uses feature not supported by repository version 1")
 		}
 	}
 
@@ -678,7 +678,7 @@ func (r *Repository) CreateIndexFromPacks(ctx context.Context, packsize map[rest
 
 	err = wg.Wait()
 	if err != nil {
-		return invalid, errors.Fatal(err.Error())
+		return invalid, err
 	}
 
 	return invalid, nil
@@ -723,9 +723,9 @@ func (r *Repository) SearchKey(ctx context.Context, password string, maxKeys int
 	r.keyID = key.ID()
 	cfg, err := restic.LoadConfig(ctx, r)
 	if err == crypto.ErrUnauthenticated {
-		return errors.Fatalf("config or key %v is damaged: %v", key.ID(), err)
+		return fmt.Errorf("config or key %v is damaged: %w", key.ID(), err)
 	} else if err != nil {
-		return errors.Fatalf("config cannot be loaded: %v", err)
+		return fmt.Errorf("config cannot be loaded: %w", err)
 	}
 
 	r.setConfig(cfg)