whereused --historical

Does not check the reflog, but otherwise works.

It's possible for it to display something that is not an annexed file,
if a non-annexed file somehow ends up containing something that looks
like the key's name. This seems very unlikely to happen, and it would
add a lot of complexity to detect it and somehow skip over that file,
since the git log would need to either be run again, or not limited to 1
result and canceled once enough results have been read.

Also, it kind of seems ok, if a file refers to a key, to consider that
as a place the key was used, for some definition of used. So, I punted
on dealing with that. May revisit later.

Sponsored-by: Brock Spratlen on Patreon

Git/DiffTree.hs

@@ -15,6 +15,7 @@ module Git.DiffTree (
 	diffFiles,
 	diffLog,
 	commitDiff,
+	parseDiffRaw,
 ) where
 
 import qualified Data.ByteString as B
@@ -116,9 +117,13 @@ parseDiffRaw l = go l
 	go (s:[]) = error $ "diff-tree parse error near \"" ++ decodeBL' s ++ "\""
 
 -- :<srcmode> SP <dstmode> SP <srcsha> SP <dstsha> SP <status>
+--
+-- May be prefixed with a newline, which git log --pretty=format
+-- adds to the first line of the diff, even with -z.
 parserDiffRaw :: RawFilePath -> A.Parser DiffTreeItem
 parserDiffRaw f = DiffTreeItem
-	<$ A8.char ':'
+	<$ A.option '\n' (A8.char '\n')
+	<* A8.char ':'
 	<*> octal
 	<* A8.char ' '
 	<*> octal