dune

(* -*- tuareg -*- *)
open StdLabels
open Jbuild_plugin.V1

let split_on_char ~sep s =
  let r = ref [] in
  let j = ref (String.length s) in
  for i = String.length s - 1 downto 0 do
    if String.unsafe_get s i = sep
    then (
      r := String.sub s ~pos:(i + 1) ~len:(!j - i - 1) :: !r;
      j := i )
  done;
  String.sub s ~pos:0 ~len:!j :: !r

let git_version =
  if not (try Sys.is_directory ".git" with _ -> false)
  then ""
  else
    match run_and_read_lines "git log -n1 --pretty=format:%h" with
    | version :: _ -> version
    | [] -> ""

let version =
  let ic = open_in "VERSION" in
  let version = input_line ic in
  close_in ic; version

let extra_warnings =
  let v = split_on_char ~sep:'.' ocaml_version in
  if v < ["4"; "03"] then "-45" else ""

let () =
  send
  @@ Printf.sprintf
       {|

(env
 (dev
  (flags
   (:standard -w +a-4-40-41-42-44-48-58-66%s))))

(rule
  (targets version.ml.in)
  (action (with-stdout-to %%{targets}
           (echo "let s = \"%s\"\nlet git_version = \"%s\""))))
|}
       extra_warnings
       version
       git_version