From 9cc963ce7bc91592a301feca1e2238bc17448bd8 Mon Sep 17 00:00:00 2001
From: Stephen Sherratt <stephen@sherra.tt>
Date: Wed, 22 Feb 2023 15:45:41 +1100
Subject: [PATCH] More consise error message printing

---
 lib/dev_repo.ml  |  2 +-
 lib/duniverse.ml | 18 +++++++-----------
 2 files changed, 8 insertions(+), 12 deletions(-)

diff --git a/lib/dev_repo.ml b/lib/dev_repo.ml
index 651ff9eca..30fbea196 100644
--- a/lib/dev_repo.ml
+++ b/lib/dev_repo.ml
@@ -5,7 +5,7 @@ type t = string
 let compare = String.compare
 let from_string s = s
 let to_string t = t
-let pp fmt t = Format.fprintf fmt "%s" t
+let pp = Fmt.string
 
 let rec repeat_while_some x ~f =
   match f x with None -> x | Some x -> repeat_while_some x ~f
diff --git a/lib/duniverse.ml b/lib/duniverse.ml
index 035edad3f..5abac2f9a 100644
--- a/lib/duniverse.ml
+++ b/lib/duniverse.ml
@@ -266,20 +266,16 @@ let dev_repo_package_map_to_repos dev_repo_package_map =
     | Some (dir, dev_repos) ->
         let dir_path = Fpath.(Config.vendor_dir / dir) in
         let message_first_line =
-          Format.asprintf
-            "Multiple dev-repos would be vendored into the directory: %a"
+          Fmt.str "Multiple dev-repos would be vendored into the directory: %a"
             Fpath.pp dir_path
         in
-        let message_dev_repos =
-          Format.sprintf "Dev-repos:\n%s"
-            (List.map dev_repos ~f:(fun dev_repo ->
-                 Format.asprintf "- %a" Dev_repo.pp dev_repo)
-            |> String.concat ~sep:"\n")
+        let dev_repos_pp =
+          Fmt.list
+            ~sep:Fmt.(const char '\n')
+            (fun ppf dev_repo -> Fmt.pf ppf "- %a" Dev_repo.pp dev_repo)
         in
-        let message =
-          [ message_first_line; message_dev_repos ] |> String.concat ~sep:"\n"
-        in
-        Error (`Msg message)
+        Rresult.R.error_msgf "%s\nDev-repos:\n%a" message_first_line
+          dev_repos_pp dev_repos
   in
   Ok (List.map ~f:snd repo_by_dev_repo)