support direct mode repositories with core.bare=true (not yet default)

Direct mode repositories can now have core.bare=true set, to prevent
accidentally running git commands that try to operate on the work tree,
and so do the wrong thing.

This is not yet the default, and it causes known problems for git-annex sync
due to receive.denyCurrentBranch not working in bare repositories.

This commit was sponsored by Richard Hartmann.

Annex.hs

@@ -12,7 +12,6 @@ module Annex (
 	AnnexState(..),
 	PreferredContentMap,
 	new,
-	newState,
 	run,
 	eval,
 	getState,
@@ -41,6 +40,7 @@ import Control.Concurrent
 import Common
 import qualified Git
 import qualified Git.Config
+import Git.Types hiding (remotes)
 import Git.CatFile
 import Git.CheckAttr
 import Git.CheckIgnore
@@ -112,9 +112,9 @@ data AnnexState = AnnexState
 	}
 
 newState :: Git.Repo -> AnnexState
-newState gitrepo = AnnexState
-	{ repo = gitrepo
-	, gitconfig = extractGitConfig gitrepo
+newState r = AnnexState
+	{ repo = if annexDirect c then fixupDirect r else r
+	, gitconfig = c
 	, backends = []
 	, remotes = []
 	, output = defaultMessageState
@@ -144,6 +144,8 @@ newState gitrepo = AnnexState
 	, inodeschanged = Nothing
 	, useragent = Nothing
 	}
+  where
+  	c = extractGitConfig r
 
 {- Makes an Annex state object for the specified git repo.
  - Ensures the config is read, if it was not already. -}
@@ -247,3 +249,13 @@ withCurrentState :: Annex a -> Annex (IO a)
 withCurrentState a = do
 	s <- getState id
 	return $ eval s a
+
+{- Direct mode repos have core.bare=true, but are not really bare.
+ - Fix up the Repo to be a non-bare repo, and arrange for git commands
+ - run by git-annex to be passed parameters that override this setting. -}
+fixupDirect :: Git.Repo -> Git.Repo
+fixupDirect r@(Repo { location = Local { gitdir = d, worktree = Nothing } }) = r
+	{ location = Local { gitdir = d </> ".git", worktree = Just d }
+	, gitGlobalOpts = gitGlobalOpts r ++ [Param "-c", Param "core.bare=false"]
+	}
+fixupDirect r = r