deal with cloning a repo that has an ajdusted branch checked out

Annex/AdjustedBranch.hs

@@ -18,6 +18,7 @@ module Annex.AdjustedBranch (
 	adjustToCrippledFileSystem,
 	updateAdjustedBranch,
 	propigateAdjustedCommits,
+	checkAdjustedClone,
 ) where
 
 import Annex.Common
@@ -419,3 +420,17 @@ diffTreeToTreeItem dti = TreeItem
 	(Git.DiffTree.file dti)
 	(Git.DiffTree.dstmode dti)
 	(Git.DiffTree.dstsha dti)
+
+{- Cloning a repository that has an adjusted branch checked out will
+ - result in the clone having the same adjusted branch checked out -- but
+ - the origbranch won't exist in the clone. Create the origbranch. -}
+checkAdjustedClone :: Annex ()
+checkAdjustedClone = go =<< inRepo Git.Branch.current
+  where
+	go Nothing = return ()
+	go (Just currbranch) = case adjustedToOriginal currbranch of
+		Nothing -> return ()
+		Just (_adj, origbranch) -> 
+			unlessM (inRepo $ Git.Ref.exists origbranch) $ do
+				let remotebranch = Git.Ref.underBase "refs/remotes/origin" origbranch
+				inRepo $ Git.Branch.update' origbranch remotebranch

Annex/Init.hs

@@ -105,6 +105,7 @@ initialize' mversion = do
 		, unlessM isBare
 			switchHEADBack
 		)
+	checkAdjustedClone
 	createInodeSentinalFile False
 
 uninitialize :: Annex ()

doc/design/adjusted_branches.mdwn

@@ -351,8 +351,6 @@ into adjusted view worktrees.]
   will make copies of the content of annexed files, so this would need
   to checkout the adjusted branch some other way. Maybe generalize so this
   more efficient checkout is available as a git-annex command?
-* Cloning a repo that has an adjusted branch checked out gets into an ugly
-  state.
 * There are potentially races in code that assumes a branch like
   master is not being changed by someone else. In particular,
   propigateAdjustedCommits rebases the adjusted branch on top of master.