enableremote: Better handling of the unusual case where multiple special remotes have been initialized with the same name

Before it would pick one at random, though preferring ones that were not
dead over dead ones.

Now, if one is dead and the other not, it will use the non-dead one. But if
both are not dead, or both dead, it will error out, suggesting the user
clarify what they want to enable.

Sponsored-by: Luke Shumaker on Patreon

Annex/SpecialRemote.hs

@@ -1,6 +1,6 @@
 {- git-annex special remote configuration
  -
- - Copyright 2011-2019 Joey Hess <id@joeyh.name>
+ - Copyright 2011-2021 Joey Hess <id@joeyh.name>
  -
  - Licensed under the GNU AGPL version 3 or higher.
  -}
@@ -25,16 +25,22 @@ import qualified Types.Remote as Remote
 import Git.Types (RemoteName)
 
 import qualified Data.Map as M
-import Data.Ord
 
 {- See if there's an existing special remote with this name.
  -
- - Prefer remotes that are not dead when a name appears multiple times. -}
+ - Remotes that are not dead come first in the list
+ - when a name appears multiple times. -}
 findExisting :: RemoteName -> Annex (Maybe (UUID, RemoteConfig, Maybe (ConfigFrom UUID)))
 findExisting name = do
+	(a, b) <- findExisting' name
+	return (headMaybe (a++b))
+
+{- Dead remotes with the name are in the second list, all others in the
+ - first list. -}
+findExisting' :: RemoteName -> Annex ([(UUID, RemoteConfig, Maybe (ConfigFrom UUID))], [(UUID, RemoteConfig, Maybe (ConfigFrom UUID))])
+findExisting' name = do
 	t <- trustMap
-	headMaybe
-		. sortBy (comparing $ \(u, _, _) -> Down $ M.lookup u t)
+	partition (\(u, _, _) -> M.lookup u t /= Just DeadTrusted)
 		. findByRemoteConfig (\c -> lookupName c == Just name)
 		<$> Logs.Remote.remoteConfigMap
 

CHANGELOG

@@ -3,6 +3,8 @@ git-annex (8.20211232) UNRELEASED; urgency=medium
   * export: When a non-annexed symlink is in the tree to be exported, skip it.
   * import: When the previously exported tree contained a non-annexed symlink,
     preserve it in the imported tree so it does not get deleted.
+  * enableremote: Better handling of the unusual case where
+    multiple special remotes have been initialized with the same name.
 
  -- Joey Hess <id@joeyh.name>  Mon, 03 Jan 2022 14:01:14 -0400
 

Command/EnableRemote.hs

@@ -43,8 +43,13 @@ start [] = unknownNameError "Specify the remote to enable."
 start (name:rest) = go =<< filter matchingname <$> Annex.getGitRemotes
   where
 	matchingname r = Git.remoteName r == Just name
-	go [] = startSpecialRemote name (Logs.Remote.keyValToConfig Proposed rest)
-		=<< SpecialRemote.findExisting name
+	go [] = 
+		let use = startSpecialRemote name (Logs.Remote.keyValToConfig Proposed rest)
+		in SpecialRemote.findExisting' name >>= \case
+			-- enable dead remote only when there is no
+			-- other remote with the same name
+			([], l) -> use l
+			(l, _) -> use l
 	go (r:_) = do
 		-- This could be either a normal git remote or a special
 		-- remote that has an url (eg gcrypt).
@@ -69,16 +74,16 @@ startNormalRemote name restparams r
 	ai = ActionItemOther (Just name)
 	si = SeekInput [name]
 
-startSpecialRemote :: Git.RemoteName -> Remote.RemoteConfig -> Maybe (UUID, Remote.RemoteConfig, Maybe (SpecialRemote.ConfigFrom UUID)) -> CommandStart
-startSpecialRemote name config Nothing = do
+startSpecialRemote :: Git.RemoteName -> Remote.RemoteConfig -> [(UUID, Remote.RemoteConfig, Maybe (SpecialRemote.ConfigFrom UUID))] -> CommandStart
+startSpecialRemote name config [] = do
 	m <- SpecialRemote.specialRemoteMap
 	confm <- Logs.Remote.remoteConfigMap
 	Remote.nameToUUID' name >>= \case
 		Right u | u `M.member` m ->
 			startSpecialRemote name config $
-				Just (u, fromMaybe M.empty (M.lookup u confm), Nothing)
+				[(u, fromMaybe M.empty (M.lookup u confm), Nothing)]
 		_ -> unknownNameError "Unknown remote name."
-startSpecialRemote name config (Just (u, c, mcu)) =
+startSpecialRemote name config ((u, c, mcu):[]) =
 	starting "enableremote" ai si $ do
 		let fullconfig = config `M.union` c	
 		t <- either giveup return (SpecialRemote.findType fullconfig)
@@ -89,6 +94,8 @@ startSpecialRemote name config (Just (u, c, mcu)) =
   where
 	ai = ActionItemOther (Just name)
 	si = SeekInput [name]
+startSpecialRemote _ _ _ =
+	giveup "Multiple remotes have that name. Either use git-annex renameremote to rename them, or specify the uuid of the remote to enable."
 
 performSpecialRemote :: RemoteType -> UUID -> R.RemoteConfig -> R.RemoteConfig -> RemoteGitConfig -> Maybe (SpecialRemote.ConfigFrom UUID) -> CommandPerform
 performSpecialRemote t u oldc c gc mcu = do