Merge pull request 'last_modified: don't find_blob; find the commit!' (!10) from fix-last_modified into main

Reviewed-on: #10
Reviewed-by: dinosaure <romain.calascibetta@gmail.com>

src/git_kv.ml

@@ -463,12 +463,19 @@ module Make (Pclock : Mirage_clock.PCLOCK) = struct
 
   let last_modified t key =
     let open Lwt.Infix in
-    find_blob t key >>=
-    Option.fold
-      ~none:(Lwt.return (Error (`Not_found key)))
-      ~some:(fun head ->
-          Store.read_exn t.store head >|= function
-          | Commit c ->
+    match t.committed, t.head with
+    | None, None ->
+      Lwt.return (Error (`Not_found key))
+    | Some _, _ ->
+      Lwt.return_ok
+        (Option.fold
+           ~none:Ptime.epoch
+           ~some:Fun.id (Ptime.of_float_s (Int64.to_float (now ()))))
+    | None, Some head ->
+      (* See https://github.com/ocaml/ocaml/issues/9301 why we have the
+         intermediate [r] value. *)
+      let+ r = Store.read_exn t.store head in
+      let[@warning "-8"] Commit c = r in
       let author = Git_commit.author c in
       let secs, tz_offset = author.Git.User.date in
       let secs =
@@ -486,10 +493,6 @@ module Make (Pclock : Mirage_clock.PCLOCK) = struct
           ~some:Fun.id (Ptime.of_float_s (Int64.to_float secs))
       in
       Ok ts
-          | _ ->
-            Ok (Option.fold
-              ~none:Ptime.epoch
-              ~some:Fun.id (Ptime.of_float_s (Int64.to_float (now ())))))
 
   let digest t key =
     let open Lwt.Infix in