From fbf4d89e8285e6f92ef2f752f7f87f81c3c70033 Mon Sep 17 00:00:00 2001
From: Joey Hess <joeyh@joeyh.name>
Date: Fri, 11 Mar 2016 12:47:14 -0400
Subject: [PATCH] extract commit parent(s)

---
 Git/CatFile.hs | 8 +++++---
 Git/Types.hs   | 1 +
 2 files changed, 6 insertions(+), 3 deletions(-)

diff --git a/Git/CatFile.hs b/Git/CatFile.hs
index 455f192a02..d6f7707bca 100644
--- a/Git/CatFile.hs
+++ b/Git/CatFile.hs
@@ -125,15 +125,17 @@ catCommit h commitref = go <$> catObjectDetails h commitref
 parseCommit :: L.ByteString -> Maybe Commit
 parseCommit b = Commit
 	<$> (extractSha . L8.unpack =<< field "tree")
+	<*> (mapMaybe (extractSha . L8.unpack) <$> fields "parent")
 	<*> (parsemetadata <$> field "author")
 	<*> (parsemetadata <$> field "committer")
 	<*> Just (L8.unpack $ L.intercalate (L.singleton nl) message)
   where
-	field n = M.lookup (fromString n) fields
-	fields = M.fromList ((map breakfield) header)
+	field n = headMaybe =<< fields n
+	fields n = M.lookup (fromString n) fieldmap
+	fieldmap = M.fromListWith (++) ((map breakfield) header)
 	breakfield l =
 		let (k, sp_v) = L.break (== sp) l
-		in (k, L.drop 1 sp_v)
+		in (k, [L.drop 1 sp_v])
 	(header, message) = separate L.null ls
 	ls = L.split nl b
 
diff --git a/Git/Types.hs b/Git/Types.hs
index 4fa49be5c0..44135738da 100644
--- a/Git/Types.hs
+++ b/Git/Types.hs
@@ -105,6 +105,7 @@ fromBlobType SymlinkBlob = 0o120000
 
 data Commit = Commit
 	{ commitTree :: Sha
+	, commitParent :: [Sha]
 	, commitAuthorMetaData :: CommitMetaData
 	, commitCommitterMetaData :: CommitMetaData
 	, commitMessage :: String