commit 7c7ba693333c06aa59d0a915e0b4f44d56d7da0e
Author: Trevor Elliott <awesomelyawesome@gmail.com>
Date:   Mon Oct 15 21:40:45 2012 -0700

    Update for tar >= 0.4

	Modified   cabal-dev.cabal
	Modified   src/Distribution/Dev/AddSource.hs
diff --git a/src/Distribution/Dev/AddSource.hs b/src/Distribution/Dev/AddSource.hs
index e43730d..aa4d12a 100644
--- a/src/Distribution/Dev/AddSource.hs
+++ b/src/Distribution/Dev/AddSource.hs
@@ -164,7 +164,7 @@ readExistingIndex sandbox =
       forceEntries es =
         let step _ l@(Left _) = l
             step x (Right xs) = Right (x:xs)
-            es' = T.foldEntries step (Right []) Left es
+            es' = T.foldEntries step (Right []) (Left . show) es
         in either (const 0) length es' `seq` return es'
 
 
@@ -344,7 +344,7 @@ forcedBS :: L.ByteString -> IO L.ByteString
 forcedBS bs = forceBS bs >> return bs
 
 -- |Extract a cabal file from a package tarball
-extractCabalFile :: T.Entries -> Maybe (PackageIdentifier, L.ByteString, PackageDescription)
+extractCabalFile :: T.Entries T.FormatError -> Maybe (PackageIdentifier, L.ByteString, PackageDescription)
 extractCabalFile = T.foldEntries step Nothing (const Nothing)
     where
       step ent Nothing = (,,) <$> entPackageId ent <*> entBytes ent <*> (parseDesc $ entBytes ent)