Fix dune targets and dependencies

src/dune_lang/action.mli

@@ -54,7 +54,7 @@ end
 
 module File_perm : sig
   (** File mode, for when creating files. We only allow what Dune takes into
-      account when memoizing commands. *)
+          account when memoizing commands. *)
 
   type t = File_perm.t =
     | Normal
@@ -95,8 +95,8 @@ type t =
   | Chdir of String_with_vars.t * t
   | Setenv of String_with_vars.t * String_with_vars.t * t
   (* It's not possible to use a build String_with_vars.t here since jbuild
-     supports redirecting to /dev/null. In [dune] files this is replaced with
-     %{null} *)
+         supports redirecting to /dev/null. In [dune] files this is replaced with
+         %{null} *)
   | Redirect_out of Outputs.t * String_with_vars.t * File_perm.t * t
   | Redirect_in of Inputs.t * String_with_vars.t * t
   | Ignore of Outputs.t * t

src/dune_lang/pform.ml

@@ -55,6 +55,7 @@ module Var = struct
       | Arch
       | Sys_ocaml_version
       | Section_dir of Section.t
+      | Target of string
 
     let compare = Poly.compare
 
@@ -75,6 +76,7 @@ module Var = struct
       | Sys_ocaml_version -> variant "Sys_ocaml_version" []
       | Section_dir section ->
         variant "Section_dir" [ string (Section.to_string section) ]
+      | Target target -> variant "Target" [ string target ]
     ;;
 
     let encode_to_latest_dune_lang_version = function
@@ -91,6 +93,7 @@ module Var = struct
       | Arch -> "arch"
       | Sys_ocaml_version -> "sys_ocaml_version"
       | Section_dir section -> Section.to_string section
+      | Target target -> target
     ;;
   end
 
@@ -102,7 +105,7 @@ module Var = struct
     | First_dep
     | Deps
     | Targets
-    | Target
+    | Target of string
     | Cc
     | Cxx
     | Ccomp_type
@@ -141,9 +144,16 @@ module Var = struct
     | Toolchain
     | Pkg of Pkg.t
 
-  let compare : t -> t -> Ordering.t = Poly.compare
+  let compare (a : t) (b : t) : Ordering.t =
+    match a, b with
+    | Target a, Target b -> String.compare a b
+    | Target _, _ -> Lt
+    | _, Target _ -> Gt
+    | a, b -> Poly.compare a b
+  ;;
 
   let to_dyn = function
+    | Target name -> Dyn.Variant ("Target", [ String name ])
     | User_var v -> Dyn.Variant ("User_var", [ String v ])
     | t ->
       let open Dyn in
@@ -155,7 +165,7 @@ module Var = struct
        | First_dep -> variant "First_dep" []
        | Deps -> variant "Deps" []
        | Targets -> variant "Targets" []
-       | Target -> variant "Target" []
+       | Target _ -> assert false (* Handled above *)
        | Cc -> variant "Cc" []
        | Cxx -> variant "Cxx" []
        | Ccomp_type -> variant "Ccomp_type" []
@@ -465,7 +475,7 @@ let encode_to_latest_dune_lang_version t =
        | First_dep -> None
        | Deps -> Some "deps"
        | Targets -> Some "targets"
-       | Target -> Some "target"
+       | Target _ -> Some "target"
        | Cc -> Some "cc"
        | Cxx -> Some "cxx"
        | Ccomp_type -> Some "ccomp_type"
@@ -654,7 +664,8 @@ module Env = struct
       in
       let other : (string * Var.t With_versioning_info.t) list =
         [ "targets", since ~version:(1, 0) Var.Targets
-        ; "target", since ~version:(1, 11) Var.Target
+        ; "target", since ~version:(1, 11) (Var.Target "")
+          (* or some appropriate default value *)
         ; "deps", since ~version:(1, 0) Var.Deps
         ; "project_root", since ~version:(1, 0) Var.Project_root
         ; ( "<"
@@ -816,3 +827,36 @@ module Env = struct
       ~f:(fun _ _ _ -> assert false)
   ;;
 end
+
+let parse_target_var s =
+  match String.split_on_char ~sep:':' s with
+  | [ "target"; name ] -> Some (Var (Var.Target name))
+  | [ "targets" ] -> Some (Var Var.Targets)
+  | _ -> None
+;;
+
+let parse_pkg_target_var s =
+  match String.split_on_char ~sep:':' s with
+  | [ "pkg"; pkg_name; "target"; target_name ] ->
+    Some (Var.Pkg.Target (pkg_name ^ ":" ^ target_name))
+  | [ "pkg"; pkg_name; section ] ->
+    (match Var.Pkg.Section.of_string section with
+     | Some section -> Some (Var.Pkg.Section_dir section)
+     | None -> Some (Var.Pkg.Target (pkg_name ^ ":" ^ section)))
+  | [ "pkg"; var ] ->
+    (match var with
+     | "switch" -> Some Var.Pkg.Switch
+     | "os" -> Some Var.Pkg.Os
+     | "os_version" -> Some Var.Pkg.Os_version
+     | "os_distribution" -> Some Var.Pkg.Os_distribution
+     | "os_family" -> Some Var.Pkg.Os_family
+     | "build" -> Some Var.Pkg.Build
+     | "prefix" -> Some Var.Pkg.Prefix
+     | "user" -> Some Var.Pkg.User
+     | "group" -> Some Var.Pkg.Group
+     | "jobs" -> Some Var.Pkg.Jobs
+     | "arch" -> Some Var.Pkg.Arch
+     | "sys_ocaml_version" -> Some Var.Pkg.Sys_ocaml_version
+     | target -> Some (Var.Pkg.Target target))
+  | _ -> None
+;;

src/dune_lang/pform.mli

@@ -34,6 +34,7 @@ module Var : sig
       | Arch
       | Sys_ocaml_version
       | Section_dir of Section.t
+      | Target of string
 
     val compare : t -> t -> Ordering.t
     val to_dyn : t -> Dyn.t
@@ -47,7 +48,7 @@ module Var : sig
     | First_dep
     | Deps
     | Targets
-    | Target
+    | Target of string
     | Cc
     | Cxx
     | Ccomp_type
@@ -207,3 +208,6 @@ module Env : sig
   val to_stamp : t -> stamp
   val to_dyn : t -> Dyn.t
 end
+
+val parse_target_var : string -> t option
+val parse_pkg_target_var : string -> Var.Pkg.t option

src/dune_lang/string_with_vars.mli

@@ -33,7 +33,7 @@ val add_user_vars_to_decoding_env
   -> ('a, 'k) Decoder.parser
 
 (** [t] generated by the OCaml code. The first argument should be [__POS__].
-    [quoted] says whether the string is quoted ([false] by default). *)
+        [quoted] says whether the string is quoted ([false] by default). *)
 val virt_pform : ?quoted:bool -> string * int * int * int -> Pform.t -> t
 
 val virt_text : string * int * int * int -> string -> t
@@ -57,12 +57,12 @@ val pform_only : t -> Pform.t option
 
 module Mode : sig
   (** How many values expansion of a template must produce.
-
-      The caller always knows which of the contexts below it requires, therefore
-      it can specify this to the expansion functions. This allows us to return a
-      precise result type from the expansion, and do some validation to make
-      sure we aren't expanding into multiple values in cases where it's not
-      allowed. *)
+    
+          The caller always knows which of the contexts below it requires, therefore
+          it can specify this to the expansion functions. This allows us to return a
+          precise result type from the expansion, and do some validation to make
+          sure we aren't expanding into multiple values in cases where it's not
+          allowed. *)
   type (_, _) t =
     | Single : (Value.Deferred_concat.t, Value.t) t
     (** Expansion must produce a single value *)
@@ -104,8 +104,8 @@ module type Expander = sig
   type 'a app
 
   (** [expand ~f] attempts to expand all percent forms in a template. If [f]
-      returns [None] for any variable (no substitution was found), then this
-      function will raise. *)
+          returns [None] for any variable (no substitution was found), then this
+          function will raise. *)
   val expand
     :  t
     -> mode:(_, 'value) Mode.t
@@ -114,7 +114,7 @@ module type Expander = sig
     -> 'value app
 
   (** Behaves the same as [expand] except the pform expander [f] returns a
-      result and errors are propagated *)
+          result and errors are propagated *)
   val expand_result
     :  t
     -> mode:(_, 'value) Mode.t
@@ -129,7 +129,7 @@ module type Expander = sig
     -> ('deferred_concat, 'error) result app
 
   (** [expand_as_much_as_possible] expands all variables for which [f] returns
-      [None] and left other unexpanded. *)
+          [None] and left other unexpanded. *)
   val expand_as_much_as_possible
     :  t
     -> dir:Path.t