Revised windows init2

src/client/opamAction.ml

@@ -528,9 +528,8 @@ let compilation_env t opam =
       (OpamFile.OPAM.build_env opam)
   in
   let cygwin_env =
-    match OpamSysInteract.Cygwin.cygbin_opt t.switch_global.config with
+    match OpamCoreConfig.(!r.cygbin) with
     | Some cygbin ->
-      let cygbin = OpamFilename.Dir.to_string cygbin in
       [ OpamTypesBase.env_update_resolved "PATH" Cygwin cygbin
           ~comment:"Cygwin path"
       ] @ (match OpamCoreConfig.(!r.git_location) with

src/client/opamInitDefaults.ml

@@ -149,7 +149,6 @@ let required_tools ~sandboxing () =
 let required_packages_for_cygwin =
   [
     "diffutils";
-    "git"; (* XXX hg & mercurial ? *)
     "make";
     "patch";
     "tar";

src/client/opamSolution.ml

@@ -1146,34 +1146,11 @@ let get_depexts ?(force=false) ?(recover=false) t packages =
   print_depext_msg (avail, nf);
   avail
 
-let install_depexts ?(force_depext=false) ?(confirm=true) t packages =
-  let confirm =
-    confirm && not (OpamSysInteract.Cygwin.is_internal t.switch_global.config)
-  in
-  let sys_packages =
-    get_depexts ~force:force_depext ~recover:force_depext t packages
-  in
-  let env = t.switch_global.global_variables in
-  let config = t.switch_global.config in
-  let map_sysmap f t =
-    let sys_packages =
-      OpamPackage.Set.fold (fun nv sys_map ->
-          match OpamPackage.Map.find_opt nv sys_map with
-          | Some status ->
-            OpamPackage.Map.add
-              nv { status with OpamSysPkg.s_available =
-                                 f status.OpamSysPkg.s_available }
-              sys_map
-          | None -> sys_map)
-        packages
-        (Lazy.force t.sys_packages)
-    in
-    { t with sys_packages = lazy sys_packages }
-  in
+let install_sys_packages ~map_sysmap ~confirm env config sys_packages t =
   let rec entry_point t sys_packages =
     if OpamClientConfig.(!r.fake) then
       (print_command sys_packages; t)
-    else if OpamFile.Config.depext_run_installs t.switch_global.config then
+    else if OpamFile.Config.depext_run_installs config then
       if confirm then menu t sys_packages else auto_install t sys_packages
     else
       manual_install t sys_packages
@@ -1212,6 +1189,8 @@ let install_depexts ?(force_depext=false) ?(confirm=true) t packages =
     | `Ignore -> bypass t
     | `Quit -> give_up_msg (); OpamStd.Sys.exit_because `Aborted
   and print_command sys_packages =
+    if OpamSysPoll.os_distribution env = Some "cygwin" then
+      OpamSysInteract.Cygwin.check_setup None;
     let commands =
       OpamSysInteract.install_packages_commands ~env config sys_packages
       |> List.map (fun ((`AsAdmin c | `AsUser c), a) -> c::a)
@@ -1242,6 +1221,8 @@ let install_depexts ?(force_depext=false) ?(confirm=true) t packages =
     | `Quit -> give_up ()
   and auto_install t sys_packages =
     try
+      if OpamSysPoll.os_distribution env = Some "cygwin" then
+        OpamSysInteract.Cygwin.check_setup None;
       OpamSysInteract.install ~env config sys_packages; (* handles dry_run *)
       map_sysmap (fun _ -> OpamSysPkg.Set.empty) t
     with Failure msg ->
@@ -1297,6 +1278,35 @@ let install_depexts ?(force_depext=false) ?(confirm=true) t packages =
     entry_point t sys_packages
   with Sys.Break as e -> OpamStd.Exn.finalise e give_up_msg
 
+let install_depexts ?(force_depext=false) ?(confirm=true) t packages =
+  let map_sysmap f t =
+    let sys_packages =
+      OpamPackage.Set.fold (fun nv sys_map ->
+          match OpamPackage.Map.find_opt nv sys_map with
+          | Some status ->
+            OpamPackage.Map.add
+              nv { status with OpamSysPkg.s_available =
+                                 f status.OpamSysPkg.s_available }
+              sys_map
+          | None -> sys_map)
+        packages
+        (Lazy.force t.sys_packages)
+    in
+    { t with sys_packages = lazy sys_packages }
+  in
+  let confirm =
+    confirm && not (OpamSysInteract.Cygwin.is_internal t.switch_global.config)
+  in
+  let sys_packages =
+    get_depexts ~force:force_depext ~recover:force_depext t packages
+  in
+  let env = t.switch_global.global_variables in
+  let config = t.switch_global.config in
+  install_sys_packages ~map_sysmap ~confirm env config sys_packages t
+
+let install_sys_packages ~confirm =
+  install_sys_packages ~map_sysmap:(fun _ () -> ()) ~confirm
+
 (* Apply a solution *)
 let apply ?ask t ~requested ?print_requested ?add_roots
     ?(skip=OpamPackage.Map.empty)

src/client/opamSolution.mli

@@ -75,12 +75,22 @@ val check_solution:
     without actually performing the action(s) on disk. *)
 val dry_run: 'a switch_state -> OpamSolver.solution -> 'a switch_state
 
+(** Given [(available, not_found)] (see {!OpamSysInteract.packages_status}),
+    displays appropriate warnings/messages on the console if either set is
+    non-empty. *)
+val print_depext_msg : OpamSysPkg.Set.t * OpamSysPkg.Set.t -> unit
+
+(** As {!install_depexts}, but supplied with a set of system packages to be
+    installed. *)
+val install_sys_packages: confirm:bool -> OpamStateTypes.gt_variables ->
+  OpamFile.Config.t -> OpamSysPkg.Set.t -> unit -> unit
+
 (* Install external dependencies of the given package set, according the depext
    configuration. If [confirm] is false, install commands are directly
    launched, without asking user (used by the `--depext-only` option). If
    [force_depext] is true, it overrides [OpamFile.Config.depext] value. *)
-val install_depexts:
-  ?force_depext:bool -> ?confirm:bool -> rw switch_state -> package_set -> rw switch_state
+val install_depexts: ?force_depext:bool -> ?confirm:bool -> rw switch_state ->
+  package_set -> rw switch_state
 
 (** {2 Atoms} *)
 

src/core/opamCompat.ml

@@ -23,6 +23,24 @@ module String = struct
   include Stdlib.String
 end
 
+module Seq = struct
+  [@@@warning "-32"]
+
+  (** NOTE: OCaml >= 4.14 *)
+  let rec find_map f xs =
+    match xs() with
+    | Seq.Nil ->
+      None
+    | Seq.Cons (x, xs) ->
+      match f x with
+      | None ->
+          find_map f xs
+      | Some _ as result ->
+          result
+
+  include Seq
+end
+
 module Either = struct
   (** NOTE: OCaml >= 4.12 *)
   type ('a, 'b) t =

src/core/opamCompat.mli

@@ -13,6 +13,11 @@ module String : sig
   val exists: (char -> bool) -> string -> bool
 end
 
+module Seq : sig
+  (* NOTE: OCaml >= 4.14 *)
+  val find_map: ('a -> 'b option) -> 'a Seq.t -> 'b option
+end
+
 module Either : sig
   (* NOTE: OCaml >= 4.12 *)
   type ('a, 'b) t =

src/core/opamProcess.ml

@@ -302,21 +302,18 @@ let string_of_info ?(color=`yellow) info =
         (OpamConsole.colorise color k) v) info;
   Buffer.contents b
 
-let resolve_command_fn = ref (fun ?env:_ ?dir:_ _ -> None)
-let set_resolve_command =
-  let called = ref false in
-  fun resolve_command ->
-    if !called then invalid_arg "Just what do you think you're doing, Dave?";
-    called := true;
-    resolve_command_fn := resolve_command
-let resolve_command cmd = !resolve_command_fn cmd
+let resolve_command ?env ?dir name =
+  let env = match env with None -> default_env () | Some e -> e in
+  match OpamStd.Sys.resolve_command ~env ?dir name with
+  | `Cmd cmd -> Some cmd
+  | `Denied | `Not_found -> None
 
 let create_process_env =
   if Sys.win32 then
     fun cmd ->
       if OpamStd.Option.map_default
           (OpamStd.Sys.is_cygwin_variant
-             ~cygbin:(OpamCoreConfig.(!r.cygbin)))
+             ?search_in_first:(OpamCoreConfig.(!r.cygbin)))
              false
              (resolve_command cmd) then
         cygwin_create_process_env cmd

src/core/opamProcess.mli

@@ -223,8 +223,9 @@ end
 type 'a job = 'a Job.Op.job
 
 (**/**)
-val set_resolve_command :
-  (?env:string array -> ?dir:string -> string -> string option) -> unit
+(** As {!OpamStd.Sys.resolve_command}, except the default for [~env] is
+    {!default_env}. *)
+val resolve_command: ?env:string array -> ?dir:string -> string -> string option
 
 (** Like Unix.create_process_env, but with correct escaping of arguments when
     invoking a cygwin executable from a native Windows executable. *)