improve adjusted branch name parsing to support adjusted view branches

An adjusted view branch has a name like
"adjusted/views/master(author=_)(unlocked)"
and so the adjustment starts at the last open paren, not the first open
paren.

Note that git-annex sync still does not do anything useful when run in
such a branch, because it does not realize that it is a view branch.
This is only groundwork for adjusted view branches.

This also fixes adjusted branches when the basis branch name contains
parens for some other reason, though that is not common in a git branch
name.

Sponsored-by: Boyd Stephen Smith Jr. on Patreon

Annex/AdjustedBranch/Name.hs

@@ -88,7 +88,7 @@ type OrigBranch = Branch
 adjustedToOriginal :: Branch -> Maybe (Adjustment, OrigBranch)
 adjustedToOriginal b
 	| adjustedBranchPrefix `S.isPrefixOf` bs = do
-		let (base, as) = separate' (== openparen) (S.drop prefixlen bs)
+		let (base, as) = separateEnd' (== openparen) (S.drop prefixlen bs)
 		adj <- deserializeAdjustment (S.takeWhile (/= closeparen) as)
 		Just (adj, Git.Ref.branchRef (Ref base))
 	| otherwise = Nothing

Utility/Misc.hs

@@ -12,6 +12,7 @@ module Utility.Misc (
 	readFileStrict,
 	separate,
 	separate',
+	separateEnd',
 	firstLine,
 	firstLine',
 	segment,
@@ -62,6 +63,13 @@ separate' c l = unbreak $ S.break c l
 		| S.null b = r
 		| otherwise = (a, S.tail b)
 
+separateEnd' :: (Word8 -> Bool) -> S.ByteString -> (S.ByteString, S.ByteString)
+separateEnd' c l = unbreak $ S.breakEnd c l
+  where
+	unbreak r@(a, b)
+		| S.null a = r
+		| otherwise = (S.init a, b)
+
 {- Breaks out the first line. -}
 firstLine :: String -> String
 firstLine = takeWhile (/= '\n')