sync: Fix parsing of gcrypt::rsync:// urls that use a relative path

Such an url is not valid; parseURI will fail on it. But git-annex doesn't
actually need to parse the url, because all it needs to do to support
syncing with it is know that it's not a local path, and use git pull and
push.

(Note that there is no good reason for the user to use such an url. An
absolute url is valid and I patched git-remote-gcrypt to support them
years ago. Still, users gonna do anything that tools allow, and
git-remote-gcrypt still supports them.)

Sponsored-by: Jack Hill on Patreon

Git/Construct.hs

@@ -140,7 +140,7 @@ fromRemotes repo = catMaybes <$> mapM construct remotepairs
 	filterkeys f = filterconfig (\(k,_) -> f k)
 	remotepairs = filterkeys isRemoteUrlKey
 	construct (k,v) = remoteNamedFromKey k $
-		fromRemoteLocation (fromConfigValue v) repo
+		fromRemoteLocation (fromConfigValue v) False repo
 
 {- Sets the name of a remote when constructing the Repo to represent it. -}
 remoteNamed :: String -> IO Repo -> IO Repo
@@ -156,9 +156,15 @@ remoteNamedFromKey k r = case remoteKeyToRemoteName k of
 	Just n -> Just <$> remoteNamed n r
 
 {- Constructs a new Repo for one of a Repo's remotes using a given
- - location (ie, an url). -}
-fromRemoteLocation :: String -> Repo -> IO Repo
-fromRemoteLocation s repo = gen $ parseRemoteLocation s repo
+ - location (ie, an url). 
+ -
+ - knownurl can be true if the location is known to be an url. This allows
+ - urls that don't parse as urls to be used, returning UnparseableUrl.
+ - If knownurl is false, the location may still be an url, if it parses as
+ - one.
+ -}
+fromRemoteLocation :: String -> Bool -> Repo -> IO Repo
+fromRemoteLocation s knownurl repo = gen $ parseRemoteLocation s knownurl repo
   where
 	gen (RemotePath p) = fromRemotePath p repo
 	gen (RemoteUrl u) = fromUrl u

Git/GCrypt.hs

@@ -55,7 +55,15 @@ encryptedRemote baserepo = go
 			    -- allows them); need to de-escape any such
 			    -- to get back the path to the repository.
 			    l' = Network.URI.unEscapeString l
-			in fromRemoteLocation l' baserepo
+			    -- gcrypt supports relative urls for rsync 
+			    -- like "rsync://host:relative/path"
+			    -- but that does not parse as a valid url
+			    -- (while the absolute urls it supports are
+			    -- valid). 
+			    -- In order to support it, force treating it as
+			    -- an url.
+			    knownurl = "rsync://" `isPrefixOf` l'
+			in fromRemoteLocation l' knownurl baserepo
 		| otherwise = notencrypted
 
 	notencrypted = giveup "not a gcrypt encrypted repository"

Git/Remote.hs

@@ -63,7 +63,7 @@ makeLegalName s = case filter legal $ replace "/" "_" s of
 	legal c = isAlphaNum c
 	
 data RemoteLocation = RemoteUrl String | RemotePath FilePath
-	deriving (Eq)
+	deriving (Eq, Show)
 
 remoteLocationIsUrl :: RemoteLocation -> Bool
 remoteLocationIsUrl (RemoteUrl _) = True
@@ -75,16 +75,18 @@ remoteLocationIsSshUrl _ = False
 
 {- Determines if a given remote location is an url, or a local
  - path. Takes the repository's insteadOf configuration into account. -}
-parseRemoteLocation :: String -> Repo -> RemoteLocation
-parseRemoteLocation s repo = ret $ calcloc s
+parseRemoteLocation :: String -> Bool -> Repo -> RemoteLocation
+parseRemoteLocation s knownurl repo = go
   where
-	ret v
+ 	s' = calcloc s
+	go
 #ifdef mingw32_HOST_OS
-		| dosstyle v = RemotePath (dospath v)
+		| dosstyle s' = RemotePath (dospath s')
 #endif
-		| scpstyle v = RemoteUrl (scptourl v)
-		| urlstyle v = RemoteUrl v
-		| otherwise = RemotePath v
+		| scpstyle s' = RemoteUrl (scptourl s')
+		| urlstyle s' = RemoteUrl s'
+		| knownurl && s' == s = RemoteUrl s'
+		| otherwise = RemotePath s'
 	-- insteadof config can rewrite remote location
 	calcloc l
 		| null insteadofs = l