Refactor variable handling (#4184)

- move variable name resolution is now done at parsing time
- pform now contains symbolic names rather than a version number and
  variable names as strings
- better error when specific variables such as "library-name" are used
  in the wrong context
- starting from 3.0, unknown variable names are always reported at
  parsing time

Signed-off-by: Jeremie Dimino <[email protected]>

CHANGES.md

@@ -23,6 +23,8 @@ Unreleased
 - Do not pass include directories containing native objects when compiling
   bytecode (#4200, @nojb)
 
+- Detect unknown variables more eagerly (#4184, @jeremiedimino)
+
 2.8.2 (21/01/2021)
 ------------------
 

bin/arg.ml

@@ -57,7 +57,9 @@ module Dep = struct
 
   let dep_parser =
     Dune_lang.Syntax.set Stanza.syntax (Active Stanza.latest_version)
-      Dep_conf.decode
+      (String_with_vars.set_decoding_env
+         (Pform.Env.initial Stanza.latest_version)
+         Dep_conf.decode)
 
   let parser s =
     match parse_alias s with

bin/top.ml

@@ -57,8 +57,8 @@ let term =
       let files_to_load =
         List.filter files ~f:(fun p ->
             let ext = Path.extension p in
-            ext = Dune_rules.Mode.compiled_lib_ext Byte
-            || ext = Dune_rules.Cm_kind.ext Cmo)
+            ext = Dune_engine.Mode.compiled_lib_ext Byte
+            || ext = Dune_engine.Cm_kind.ext Cmo)
       in
       Dune_rules.Toplevel.print_toplevel_init_file ~include_paths ~files_to_load;
       Fiber.return ())

src/dune_engine/action.ml

@@ -14,13 +14,15 @@ module Prog = struct
 
     let create ?hint ~context ~program ~loc () = { hint; context; program; loc }
 
-    let raise { context; program; hint; loc } =
+    let user_message { context; program; hint; loc } =
       let hint =
         match program with
         | "refmt" -> Some (Option.value ~default:"opam install reason" hint)
         | _ -> hint
       in
-      Utils.program_not_found ?hint ~loc ~context program
+      Utils.program_not_found_message ?hint ~loc ~context program
+
+    let raise t = raise (User_error.E (user_message t))
 
     let to_dyn { context; program; hint; loc = _ } =
       let open Dyn.Encoder in

src/dune_engine/action.mli

@@ -31,6 +31,8 @@ module Prog : sig
       -> t
 
     val raise : t -> _
+
+    val user_message : t -> User_message.t
   end
 
   type t = (Path.t, Not_found.t) result

src/dune_engine/action_dune_lang.ml

@@ -11,7 +11,7 @@ type target = String_with_vars.t
 module String_with_vars = struct
   include String_with_vars
 
-  let is_dev_null = String_with_vars.is_var ~name:"null"
+  let is_dev_null t = String_with_vars.is_pform t (Var Dev_null)
 end
 
 module type Uast =

src/dune_rules/cm_kind.ml → src/dune_engine/cm_kind.ml

@@ -1,4 +1,3 @@
-open! Dune_engine
 open Import
 
 type t =

src/dune_rules/cm_kind.mli → src/dune_engine/cm_kind.mli

@@ -1,4 +1,3 @@
-open! Dune_engine
 open Import
 
 type t =

src/dune_engine/config.ml

@@ -313,7 +313,9 @@ end)
 
 let () = Lang.register syntax ()
 
-let load_config_file p = load_exn p ~f:(fun _lang -> decode)
+let load_config_file p =
+  load_exn p ~f:(fun lang ->
+      String_with_vars.set_decoding_env (Pform.Env.initial lang.version) decode)
 
 let load_user_config_file () =
   if Path.exists user_config_file then

src/dune_engine/dialect.ml

@@ -80,11 +80,11 @@ let ocaml =
     in
     let module S = String_with_vars in
     Action_dune_lang.chdir
-      (S.make_var Loc.none "workspace_root")
+      (S.make_pform Loc.none (Var Workspace_root))
       (Action_dune_lang.run
          (S.make_text Loc.none "ocamlformat")
          [ S.make_text Loc.none (flag_of_kind kind)
-         ; S.make_var Loc.none "input-file"
+         ; S.make_pform Loc.none (Var Input_file)
          ])
   in
   let file_kind kind extension =
@@ -110,13 +110,13 @@ let reason =
         (S.make_text Loc.none "refmt")
         [ S.make_text Loc.none "--print"
         ; S.make_text Loc.none "binary"
-        ; S.make_var Loc.none "input-file"
+        ; S.make_pform Loc.none (Var Input_file)
         ]
     in
     let format =
       Action_dune_lang.run
         (S.make_text Loc.none "refmt")
-        [ S.make_var Loc.none "input-file" ]
+        [ S.make_pform Loc.none (Var Input_file) ]
     in
     { File_kind.kind
     ; extension

src/dune_engine/dune_engine.ml

@@ -52,3 +52,6 @@ module Hooks = Hooks
 module Promotion = Promotion
 module Cached_digest = Cached_digest
 module Report_error = Report_error
+module Pform = Pform
+module Cm_kind = Cm_kind
+module Mode = Mode