Deprecate opam file format 1.x support as well

CHANGES.md

@@ -20,7 +20,6 @@
 ### Changed
 
 - Attach the changelog to the annotated tag message (#283, @gpetiot)
-- Deprecate the use of delegates in `dune-release publish` (#276, #302, @pitag-ha)
 - Do not remove versioned files from the tarball anymore. We used to exclude
   `.gitignore`, `.gitattributes` and other such files from the archive.
   (#299, @NathanReb)
@@ -35,6 +34,9 @@
 
 ### Deprecated
 
+- Deprecate the use of delegates in `dune-release publish` (#276, #302, @pitag-ha)
+- Deprecate the use of opam file format 1.x (#352, @NathanReb)
+
 ### Removed
 
 - Option --name is removed from all commands. When used with

bin/opam.ml

@@ -36,6 +36,7 @@ let write_opam_file ~dry_run ~id ~url ~opam_f pkg dest_opam_file =
           (file dest_opam_file) opam_t;
       Ok ()
   | ("1.0" | "1.1" | "1.2") as v ->
+      App_log.unhappy (fun l -> l "%s" Deprecate.Opam_1_x.file_format_warning);
       App_log.status (fun l ->
           l "Upgrading opam file %a from opam format %s to 2.0" Text.Pp.path
             opam_f v);

lib/deprecate.ml

@@ -26,3 +26,15 @@ module Delegates = struct
     "Warning: You are using alternative artefacts. The use of alternative \
      artefacts is deprecated. It will be removed in version 2.0.0. %s"
 end
+
+module Opam_1_x = struct
+  let client_warning =
+    "The opam client 1.x is deprecated and its support will be dropped in \
+     dune-release 2.0.0, please switch to opam 2"
+
+  let file_format_warning =
+    "The opam file format 1.x is deprecated and its support will be dropped in \
+     dune-release 2.0.0, please switch to opam 2"
+
+  let remove_me : _ = Obj.magic ()
+end

lib/deprecate.mli

@@ -21,3 +21,17 @@ module Delegates : sig
   (** Same as [warning_usage], but for alternative artefacts instead of
       delegates. *)
 end
+
+module Opam_1_x : sig
+  val client_warning : string
+  (** Message warning users of the opam 1.x CLI tool that they need to upgade to
+      2.x to be able to be compatible with dune-release 2.0.0. *)
+
+  val file_format_warning : string
+  (** Message warning users that they need to upgrade their opam files from the
+      1.x to the 2.x format to be compatible with dune-release 2.0.0 *)
+
+  val remove_me : _
+  (** Dummy value used to flag part of the code we should remove when dropping
+      support for opam 1.x *)
+end

lib/lint.ml

@@ -107,7 +107,9 @@ let lint_opam_github_fields pkg = lint_opam_doc pkg + lint_opam_home_and_dev pkg
 let opam_lint_cmd ~opam_file_version ~opam_tool_version =
   let lint_older_format =
     match (opam_file_version, opam_tool_version) with
-    | Some "1.2", Opam.Version.V2 -> true
+    | Some "1.2", Opam.Version.V2 ->
+        let _ = Deprecate.Opam_1_x.remove_me in
+        true
     | _ -> false
   in
   Cmd.(Opam.cmd % "lint" %% on lint_older_format (v "--warn=-21-32-48"))
@@ -149,15 +151,28 @@ let opam_lint ~dry_run ~opam_file_version ~opam_tool_version opam_file =
 
 let extra_opam_lint ~opam_file_version ~opam_file pkg =
   let is_2_0_format =
-    match opam_file_version with Some "2.0" -> true | _ -> false
+    match opam_file_version with
+    | Some "2.0" -> true
+    | _ ->
+        let _ = Deprecate.Opam_1_x.remove_me in
+        false
   in
   let descr_err = if is_2_0_format then lint_descr ~opam_file pkg else 0 in
   let github_field_errs = lint_opam_github_fields pkg in
   descr_err + github_field_errs
 
+let opam_file_format_major opam_file_version =
+  match String.cut ~sep:"." opam_file_version with
+  | Some (major, _) -> int_of_string_opt major
+  | _ -> None
+
 let lint_opam ~dry_run pkg =
   Lazy.force Opam.Version.cli >>= fun opam_tool_version ->
   Pkg.opam_field_hd pkg "opam-version" >>= fun opam_file_version ->
+  (match Stdext.Option.bind ~f:opam_file_format_major opam_file_version with
+  | Some 1 ->
+      App_log.unhappy (fun l -> l "%s" Deprecate.Opam_1_x.file_format_warning)
+  | _ -> ());
   match (opam_file_version, opam_tool_version) with
   | Some "2.0", Opam.Version.V1_2_2 ->
       App_log.status (fun l ->

lib/opam.ml

@@ -323,11 +323,7 @@ module Version = struct
     | Ok (s, (_, `Exited 0)) ->
         of_string s >>= fun v ->
         if equal v V1_2_2 then
-          Logs.warn (fun l ->
-              l
-                "opam %s is deprecated, and its support will be dropped in \
-                 dune-release 2.0.0, please switch to opam 2.0"
-                s);
+          App_log.unhappy (fun l -> l "%s" Deprecate.Opam_1_x.client_warning);
         Ok v
     | Ok (_, (_, s)) -> R.error_msgf "opam: %a" OS.Cmd.pp_status s
     | Error (`Msg e) -> R.error_msgf "opam: %s" e