avoid creating work tree files in subdirectories in an edge case

A keyName could contain "/", though this is unlikely and certianly only
ever could happen with WORM keys.

The change to addunused to escape that is no problem at all.

The change to VariantFile to escape it means that different versions of
git-annex could resolve a merge conflict differently in this case, which
is unfortunate. There would be different .variant files used, so the two
resolutions would themselves merge together without additional
conflicts, but the user would have to clean up the extra .variant
files.

Annex/VariantFile.hs

@@ -10,6 +10,8 @@ module Annex.VariantFile where
 import Annex.Common
 import Utility.Hash
 
+import qualified Data.ByteString.Lazy as L
+
 variantMarker :: String
 variantMarker = ".variant-"
 
@@ -34,10 +36,10 @@ mkVariant file variant = takeDirectory file
  -}
 variantFile :: FilePath -> Key -> FilePath
 variantFile file key
-	| doubleconflict = mkVariant file (serializeKey key)
-	| otherwise = mkVariant file (shortHash $ serializeKey key)
+	| doubleconflict = mkVariant file (keyFile key)
+	| otherwise = mkVariant file (shortHash $ serializeKey' key)
   where
 	doubleconflict = variantMarker `isInfixOf` file
 
-shortHash :: String -> String
-shortHash = take 4 . show . md5 . encodeBL
+shortHash :: L.ByteString -> String
+shortHash = take 4 . show . md5

CHANGELOG

@@ -27,6 +27,8 @@ git-annex (7.20181212) UNRELEASED; urgency=medium
   * Improve uuid.log parser to preserve whitespace in repo descriptions.
   * Improve activity.log parser to not remove unknown values,
     allowing for future expansion.
+  * addunused, merge, assistant: Avoid creating work tree files in
+    subdirectories in an edge case where the key contains "/".
 
  -- Joey Hess <id@joeyh.name>  Tue, 18 Dec 2018 12:24:52 -0400
 

Command/AddUnused.hs

@@ -32,7 +32,7 @@ perform key = next $ do
 	addLink file key Nothing
 	return True
   where
-	file = "unused." ++ serializeKey key
+	file = "unused." ++ keyFile key
 
 {- The content is not in the annex, but in another directory, and
  - it seems better to error out, rather than moving bad/tmp content into