work around lack of receive.denyCurrentBranch in direct mode

Now that direct mode sets core.bare=true, git's normal prohibition about
pushing into the currently checked out branch doesn't work.

A simple fix for this would be an update hook which blocks the pushes..
but git hooks must be executable, and git-annex needs to be usable on eg,
FAT, which lacks x bits.

Instead, enabling direct mode switches the branch (eg master) to a special
purpose branch (eg annex/direct/master). This branch is not pushed when
syncing; instead any changes that git annex sync commits get written to
master, and it's pushed (along with synced/master) to the remote.

Note that initialization has been changed to always call setDirect,
even if it's just setDirect False for indirect mode. This is needed because
if the user has just cloned a direct mode repo, that nothing has synced
with before, it may have no master branch, and only a annex/direct/master.
Resulting in that branch being checked out locally too. Calling setDirect False
for indirect mode moves back out of this branch, to a new master branch,
and ensures that a manual "git push" doesn't push changes directly to
the annex/direct/master of the remote. (It's possible that the user
makes a commit w/o using git-annex and pushes it, but nothing I can do
about that really.)

This commit was sponsored by Jonathan Harrington.

1 files changed, 26 insertions, 19 deletions

diff --git a/Init.hs b/Init.hs
index 991f7d31c..453ad5ae9 100644
--- a/Init.hs
+++ b/Init.hs
@@ -53,11 +53,19 @@ genDescription Nothing = do
 initialize :: Maybe String -> Annex ()
 initialize mdescription = do
 	prepUUID
-	setVersion defaultVersion
-	checkCrippledFileSystem
 	checkFifoSupport
-	unlessBare $
+	checkCrippledFileSystem
+	unlessM isBare $
 		hookWrite preCommitHook
+	ifM (crippledFileSystem <&&> not <$> isBare)
+		( do
+			enableDirectMode
+			setDirect True
+			setVersion directModeVersion
+		, do
+			setVersion defaultVersion
+			setDirect False
+		)
 	createInodeSentinalFile
 	u <- getUUID
 	{- This will make the first commit to git, so ensure git is set up
@@ -91,8 +99,8 @@ ensureInitialized = getVersion >>= maybe needsinit checkUpgrade
 isInitialized :: Annex Bool
 isInitialized = maybe Annex.Branch.hasSibling (const $ return True) =<< getVersion
 
-unlessBare :: Annex () -> Annex ()
-unlessBare = unlessM $ fromRepo Git.repoIsLocalBare
+isBare :: Annex Bool
+isBare = fromRepo Git.repoIsLocalBare
 
 {- A crippled filesystem is one that does not allow making symlinks,
  - or removing write access from files. -}
@@ -125,25 +133,15 @@ checkCrippledFileSystem = whenM probeCrippledFileSystem $ do
 	warning "Detected a crippled filesystem."
 	setCrippledFileSystem True
 
-	{- Normally git disables core.symlinks itself when the filesystem does
- 	 - not support them, but in Cygwin, git does support symlinks, while
- 	 - git-annex, not linking with Cygwin, does not. -}
+	{- Normally git disables core.symlinks itself when the
+	 - filesystem does not support them, but in Cygwin, git
+	 - does support symlinks, while git-annex, not linking
+	 - with Cygwin, does not. -}
 	whenM (coreSymlinks <$> Annex.getGitConfig) $ do
 		warning "Disabling core.symlinks."
 		setConfig (ConfigKey "core.symlinks")
 			(Git.Config.boolConfig False)
 
-	unlessBare $ do
-		unlessM isDirect $ do
-			warning "Enabling direct mode."
-			top <- fromRepo Git.repoPath
-			(l, clean) <- inRepo $ Git.LsFiles.inRepo [top]
-			forM_ l $ \f ->
-				maybe noop (`toDirect` f) =<< isAnnexLink f
-			void $ liftIO clean
-			setDirect True
-		setVersion directModeVersion
-
 probeFifoSupport :: Annex Bool
 probeFifoSupport = do
 #ifdef mingw32_HOST_OS
@@ -166,3 +164,12 @@ checkFifoSupport = unlessM probeFifoSupport $ do
 	warning "Detected a filesystem without fifo support."
 	warning "Disabling ssh connection caching."
 	setConfig (annexConfig "sshcaching") (Git.Config.boolConfig False)
+
+enableDirectMode :: Annex ()
+enableDirectMode = unlessM isDirect $ do
+	warning "Enabling direct mode."
+	top <- fromRepo Git.repoPath
+	(l, clean) <- inRepo $ Git.LsFiles.inRepo [top]
+	forM_ l $ \f ->
+		maybe noop (`toDirect` f) =<< isAnnexLink f
+	void $ liftIO clean