diff --git a/COPYRIGHT b/COPYRIGHT
index a2324d7c58..858d7f0b74 100644
--- a/COPYRIGHT
+++ b/COPYRIGHT
@@ -29,6 +29,11 @@ Copyright: 2018 Joey Hess <id@joeyh.name>
            2013 Michael Snoyman
 License: Expat
 
+Files: Utility/Attoparsec.hs
+Copyright: 2019 Joey Hess <id@joeyh.name>
+           2007-2015 Bryan O'Sullivan
+License: BSD-3-clause
+
 Files: Utility/GitLFS.hs
 Copyright: © 2019 Joey Hess <id@joeyh.name>
 License: AGPL-3+
@@ -112,7 +117,35 @@ License: BSD-2-clause
  LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
  OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  SUCH DAMAGE.
- 
+
+License: BSD-3-clause
+ Redistribution and use in source and binary forms, with or without
+ modification, are permitted provided that the following conditions
+ are met:
+ .
+ 1. Redistributions of source code must retain the above copyright
+     notice, this list of conditions and the following disclaimer.
+ .
+ 2. Redistributions in binary form must reproduce the above copyright
+    notice, this list of conditions and the following disclaimer in the
+    documentation and/or other materials provided with the distribution.
+ .
+ 3. Neither the name of the author nor the names of his contributors
+    may be used to endorse or promote products derived from this software
+    without specific prior written permission.
+ .
+ THIS SOFTWARE IS PROVIDED BY THE CONTRIBUTORS ``AS IS'' AND ANY EXPRESS
+ OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
+ WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+ DISCLAIMED.  IN NO EVENT SHALL THE AUTHORS OR CONTRIBUTORS BE LIABLE FOR
+ ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
+ DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
+ OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
+ HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
+ STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
+ ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
+ POSSIBILITY OF SUCH DAMAGE.
+
 License: Expat
  Permission is hereby granted, free of charge, to any person obtaining
  a copy of this software and associated documentation files (the
diff --git a/Git/LsTree.hs b/Git/LsTree.hs
index aa3651a543..0196d21a1f 100644
--- a/Git/LsTree.hs
+++ b/Git/LsTree.hs
@@ -24,6 +24,7 @@ import Git.Command
 import Git.Sha
 import Git.FilePath
 import qualified Git.Filename
+import Utility.Attoparsec
 
 import Numeric
 import Data.Either
@@ -90,7 +91,7 @@ parseLsTree b = case A.parse parserLsTree b of
 parserLsTree :: A.Parser TreeItem
 parserLsTree = TreeItem
 	-- mode
-	<$> A8.decimal
+	<$> octal
 	<* A8.char ' '
 	-- type
 	<*> A.takeTill (== 32)
diff --git a/Git/Types.hs b/Git/Types.hs
index 45adc1f377..f15e334732 100644
--- a/Git/Types.hs
+++ b/Git/Types.hs
@@ -112,7 +112,7 @@ fmtObjectType TreeObject = "tree"
 
 {- Types of items in a tree. -}
 data TreeItemType = TreeFile | TreeExecutable | TreeSymlink | TreeSubmodule
-	deriving (Eq)
+	deriving (Eq, Show)
 
 {- Git uses magic numbers to denote the type of a tree item. -}
 readTreeItemType :: S.ByteString -> Maybe TreeItemType
diff --git a/Utility/Attoparsec.hs b/Utility/Attoparsec.hs
new file mode 100644
index 0000000000..bd20e8e6d9
--- /dev/null
+++ b/Utility/Attoparsec.hs
@@ -0,0 +1,21 @@
+{- attoparsec utility functions
+ -
+ - Copyright 2019 Joey Hess <id@joeyh.name>
+ - Copyright 2007-2015 Bryan O'Sullivan
+ -
+ - License: BSD-3-clause
+ -}
+
+module Utility.Attoparsec where
+
+import qualified Data.Attoparsec.ByteString as A
+import qualified Data.ByteString as B
+
+-- | Parse and decode an unsigned octal number.
+--
+-- This parser does not accept a leading @\"0o\"@ string.
+octal :: Integral a => A.Parser a
+octal = B.foldl' step 0 `fmap` A.takeWhile1 isOctDigit
+  where
+	isOctDigit w = w >= 48 && w <= 55
+	step a w = a * 8 + fromIntegral (w - 48)
diff --git a/git-annex.cabal b/git-annex.cabal
index 5d8ba73914..fa75218993 100644
--- a/git-annex.cabal
+++ b/git-annex.cabal
@@ -1020,6 +1020,7 @@ Executable git-annex
     Utility.Aeson
     Utility.Android
     Utility.Applicative
+    Utility.Attoparsec
     Utility.AuthToken
     Utility.Base64
     Utility.Batch