.noannex file

A top-level .noannex file will prevent git-annex init from being used in a
repository. This is useful for repositories that have a policy reason not
to use git-annex. The content of the file will be displayed to the user who
tries to run git-annex init.

This also affects git annex reinit and initialization via the webapp.
It does not affect automatic inits, when there's a sibling git-annex branch
already.

This commit was supported by the NSF-funded DataLad project.

Annex/Init.hs

@@ -8,6 +8,7 @@
 {-# LANGUAGE CPP #-}
 
 module Annex.Init (
+	AutoInit(..),
 	ensureInitialized,
 	isInitialized,
 	initialize,
@@ -48,6 +49,23 @@ import System.Posix.User
 import qualified Utility.LockFile.Posix as Posix
 #endif
 
+newtype AutoInit = AutoInit Bool
+
+checkCanInitialize :: AutoInit -> Annex a -> Annex a
+checkCanInitialize (AutoInit True) a = a
+checkCanInitialize (AutoInit False) a = fromRepo Git.repoWorkTree >>= \case
+	Nothing -> a
+	Just wt -> liftIO (catchMaybeIO (readFile (wt </> ".noannex"))) >>= \case
+		Nothing -> a
+		Just noannexmsg -> ifM (Annex.getState Annex.force)
+			( a
+			, do
+				warning "Initialization prevented by .noannex file (use --force to override)"
+				unless (null noannexmsg) $
+					warning noannexmsg
+				giveup "Not initialized."
+			)
+
 genDescription :: Maybe String -> Annex String
 genDescription (Just d) = return d
 genDescription Nothing = do
@@ -59,8 +77,8 @@ genDescription Nothing = do
 		Right username -> [username, at, hostname, ":", reldir]
 		Left _ -> [hostname, ":", reldir]
 
-initialize :: Maybe String -> Maybe Version -> Annex ()
-initialize mdescription mversion = do
+initialize :: AutoInit -> Maybe String -> Maybe Version -> Annex ()
+initialize ai mdescription mversion = checkCanInitialize ai $ do
 	{- Has to come before any commits are made as the shared
 	 - clone heuristic expects no local objects. -}
 	sharedclone <- checkSharedClone
@@ -70,7 +88,7 @@ initialize mdescription mversion = do
 	ensureCommit $ Annex.Branch.create
 
 	prepUUID
-	initialize' mversion
+	initialize' (AutoInit True) mversion
 	
 	initSharedClone sharedclone
 
@@ -79,8 +97,8 @@ initialize mdescription mversion = do
 
 -- Everything except for uuid setup, shared clone setup, and initial
 -- description.
-initialize' :: Maybe Version -> Annex ()
-initialize' mversion = do
+initialize' :: AutoInit -> Maybe Version -> Annex ()
+initialize' ai mversion = checkCanInitialize ai $ do
 	checkLockSupport
 	checkFifoSupport
 	checkCrippledFileSystem
@@ -131,7 +149,7 @@ ensureInitialized :: Annex ()
 ensureInitialized = getVersion >>= maybe needsinit checkUpgrade
   where
 	needsinit = ifM Annex.Branch.hasSibling
-			( initialize Nothing Nothing
+			( initialize (AutoInit True) Nothing Nothing
 			, giveup "First run: git-annex init"
 			)
 

Annex/MakeRepo.hs

@@ -76,7 +76,7 @@ initRepo False _ dir desc mgroup = inDir dir $ do
 
 initRepo' :: Maybe String -> Maybe StandardGroup -> Annex ()
 initRepo' desc mgroup = unlessM isInitialized $ do
-	initialize desc Nothing
+	initialize (AutoInit False) desc Nothing
 	u <- getUUID
 	maybe noop (defaultStandardGroup u) mgroup
 	{- Ensure branch gets committed right away so it is

CHANGELOG

@@ -16,6 +16,10 @@ git-annex (6.20171125) UNRELEASED; urgency=medium
     (Previous try had a bug.)
   * lookupkey: Support being given an absolute filename to a file
     within the current git repository.
+  * A top-level .noannex file will prevent git-annex init from being used
+    in a repository. This is useful for repositories that have a policy
+    reason not to use git-annex. The content of the file will be displayed
+    to the user who tries to run git-annex init.
 
  -- Joey Hess <id@joeyh.name>  Tue, 28 Nov 2017 13:48:44 -0400
 

Command/ConfigList.hs

@@ -45,7 +45,7 @@ findOrGenUUID = do
 		else ifM (Annex.Branch.hasSibling <||> (isJust <$> Fields.getField Fields.autoInit))
 			( do
 				liftIO checkNotReadOnly
-				initialize Nothing Nothing
+				initialize (AutoInit True) Nothing Nothing
 				getUUID
 			, return NoUUID
 			)

Command/Init.hs

@@ -45,7 +45,7 @@ start os = do
 
 perform :: InitOptions -> CommandPerform
 perform os = do
-	initialize 
+	initialize (AutoInit False)
 		(if null (initDesc os) then Nothing else Just (initDesc os))
 		(initVersion os)
 	Annex.SpecialRemote.autoEnable

Command/Reinit.hs

@@ -36,6 +36,6 @@ perform s = do
 		then return $ toUUID s
 		else Remote.nameToUUID s
 	storeUUID u
-	initialize' Nothing
+	initialize' (AutoInit False) Nothing
 	Annex.SpecialRemote.autoEnable
 	next $ return True

Command/Upgrade.hs

@@ -25,6 +25,6 @@ start :: CommandStart
 start = do
 	showStart' "upgrade" Nothing
 	whenM (isNothing <$> getVersion) $ do
-		initialize Nothing Nothing
+		initialize (AutoInit False) Nothing Nothing
 	r <- upgrade False latestVersion
 	next $ next $ return r

Test.hs

@@ -1810,7 +1810,7 @@ intmpclonerepoInDirect a = intmpclonerepo $
 		)
   where
 	isdirect = annexeval $ do
-		Annex.Init.initialize Nothing Nothing
+		Annex.Init.initialize (Annex.Init.AutoInit False) Nothing Nothing
 		Config.isDirect
 
 checkRepo :: Types.Annex a -> FilePath -> IO a

doc/git-annex-init.mdwn

@@ -23,6 +23,11 @@ mark it as dead (see [[git-annex-dead]](1)).
 
 This command is entirely safe, although usually pointless, to run inside an
 already initialized git-annex repository.
+  
+A top-level `.noannex` file will prevent git-annex init from being used
+in a repository. This is useful for repositories that have a policy
+reason not to use git-annex. The content of the file will be displayed
+to the user who tries to run git-annex init.
 
 # OPTIONS
 

doc/todo/prevent_unwanted_init.mdwn

@@ -6,3 +6,5 @@ annoying. --[[Joey]]
 This could be a git configuration setting, or it could be something
 checked into the repo. Either might make sense depending on the scope
 in which one wants to prevent the accidental init.
+
+> [[done]] using .noannex file. --[[Joey]]