upgrade: Support an edge case upgrading a v5 direct mode repo where nothing had ever been committed to the head branch

This commit was sponsored by Jack Hill on Patreon.

Annex/AdjustedBranch.hs

@@ -26,6 +26,7 @@ module Annex.AdjustedBranch (
 	adjustBranch,
 	adjustTree,
 	adjustToCrippledFileSystem,
+	commitForAdjustedBranch,
 	propigateAdjustedCommits,
 	propigateAdjustedCommits',
 	commitAdjustedTree,
@@ -334,14 +335,8 @@ adjustToCrippledFileSystem :: Annex ()
 adjustToCrippledFileSystem = do
 	warning "Entering an adjusted branch where files are unlocked as this filesystem does not support locked files."
 	checkVersionSupported
-	whenM (isNothing <$> inRepo Git.Branch.current) $ do
+	whenM (isNothing <$> inRepo Git.Branch.current) $
-		cmode <- annexCommitMode <$> Annex.getGitConfig
+		commitForAdjustedBranch []
-		void $ inRepo $ Git.Branch.commitCommand cmode
-			[ Param "--quiet"
-			, Param "--allow-empty"
-			, Param "-m"
-			, Param "commit before entering adjusted unlocked branch"
-			]
 	inRepo Git.Branch.current >>= \case
 		Just currbranch -> case getAdjustment currbranch of
 			Just curradj | curradj == adj -> return ()
@@ -358,6 +353,22 @@ adjustToCrippledFileSystem = do
 	adj = LinkAdjustment UnlockAdjustment
 	failedenter = warning "Failed to enter adjusted branch!"
 
+{- Commit before entering adjusted branch. Only needs to be done
+ - when the current branch does not have any commits yet.
+ -
+ - If something is already staged, it will be committed, but otherwise
+ - an empty commit will be made.
+ -}
+commitForAdjustedBranch :: [CommandParam] -> Annex ()
+commitForAdjustedBranch ps = do
+	cmode <- annexCommitMode <$> Annex.getGitConfig
+	void $ inRepo $ Git.Branch.commitCommand cmode $
+		[ Param "--quiet"
+		, Param "--allow-empty"
+		, Param "-m"
+		, Param "commit before entering adjusted branch"
+		] ++ ps
+
 setBasisBranch :: BasisBranch -> Ref -> Annex ()
 setBasisBranch (BasisBranch basis) new = 
 	inRepo $ Git.Branch.update' basis new

CHANGELOG

@@ -20,6 +20,8 @@ git-annex (8.20201117) UNRELEASED; urgency=medium
     locally.
   * Fix building without the torrent library.
     Thanks, Kyle Meyer.
+  * upgrade: Support an edge case upgrading a v5 direct mode repo
+    where nothing had ever been committed to the head branch.
 
  -- Joey Hess <id@joeyh.name>  Mon, 16 Nov 2020 09:38:32 -0400
 

Upgrade/V5.hs

@@ -88,7 +88,12 @@ convertDirect = do
 	 - as does annex.thin. -}
 	setConfig (annexConfig "thin") (boolConfig True)
 	Direct.setIndirect
-	cur <- fromMaybe (error "Somehow no branch is checked out")
+	cur <- inRepo Git.Branch.current >>= \case
+		Just cur -> return cur
+		Nothing -> do
+			-- Avoid running pre-commit hook.
+			commitForAdjustedBranch [Param "--no-verify"]
+			fromMaybe (giveup "Nothing is committed, and a commit failed; unable to proceed.") 
 				<$> inRepo Git.Branch.current
 	upgradeDirectWorkTree
 	removeDirectCruft

doc/bugs/v5_direct_upgrade_fail_with_annex.alwayscommit=false.mdwn

@@ -36,5 +36,4 @@ and this sequence of commands:
 Note that lack of git-annex sync, which is why the branch
 never got created. The index file has the adds staged of course.
 
-So, fixing this unusual case needs the upgrade code to go ahead and commit
+> [[fixed|done]] --[[Joey]]
-the staged index first.