Fix implementation of directives.

The compiler's ppx is only run when parsing the source file.
For config settings such as directives, this is OK when `bsc` is invoked directly, but not when part of building a project. In the latter case, the ast is compiled separately, and the builtin ppx is not run again before emitting code.

Author: cristianoc

CHANGELOG.md

@@ -51,6 +51,7 @@ These are only breaking changes for unformatted code.
 - Parser: fix location of variable when function definition `{v => ...}` is enclosed in braces https://github.com/rescript-lang/rescript-compiler/pull/5949
 - Fix issue with error messages for uncurried functions where expected and given type were swapped https://github.com/rescript-lang/rescript-compiler/pull/5973
 - Fix issue with integer overflow check https://github.com/rescript-lang/rescript-compiler/pull/6028
+- Fix implementation of directives https://github.com/rescript-lang/rescript-compiler/pull/6052
 
 #### :nail_care: Polish
 

jscomp/core/js_implementation.ml

@@ -46,7 +46,7 @@ let process_with_gentype cmt_file =
 
 let after_parsing_sig ppf outputprefix ast =
   if !Clflags.only_parse = false then (
-    Ast_config.iter_on_bs_config_sigi ast;
+    Ast_config.process_sig ast;
     if !Js_config.modules then
       output_deps_set !Location.input_name
         (Ast_extract.read_parse_and_extract Mli ast);
@@ -131,7 +131,7 @@ let after_parsing_impl ppf outputprefix (ast : Parsetree.structure) =
   if !Clflags.only_parse = false then (
     Js_config.all_module_aliases :=
       !Clflags.assume_no_mli = Mli_non_exists && all_module_alias ast;
-    Ast_config.iter_on_bs_config_stru ast;
+    Ast_config.process_str ast;
     let ast = if !Js_config.no_export then no_export ast else ast in
     if !Js_config.modules then
       output_deps_set !Location.input_name

jscomp/frontend/ast_config.ml

@@ -38,7 +38,15 @@ let signature_config_table : action_table ref = ref Map_string.empty
 let add_signature k v =
   signature_config_table := Map_string.add !signature_config_table k v
 
-let rec iter_on_bs_config_stru (x : Parsetree.structure) =
+let process_directives str =
+  Js_config.directives := []; (* Restt: multiple calls possible e.g. with bsc from the command-line *)
+  str |> List.iter(fun (item : Parsetree.structure_item) -> match item.pstr_desc with
+  | Pstr_attribute ({ txt = "directive" },
+      PStr [ { pstr_desc = Pstr_eval ({ pexp_desc = Pexp_constant (Pconst_string (d, _)) }, _) } ]) ->
+      Js_config.directives := !Js_config.directives @ [d]
+  | _ -> ())
+  
+let rec iter_on_bs_config_str (x : Parsetree.structure) =
   match x with
   | [] -> ()
   | {
@@ -51,10 +59,14 @@ let rec iter_on_bs_config_stru (x : Parsetree.structure) =
       Ext_list.iter
         (Ast_payload.ident_or_record_as_config loc payload)
         (Ast_payload.table_dispatch !structural_config_table)
-  | { pstr_desc = Pstr_attribute _ } :: rest -> iter_on_bs_config_stru rest
+  | { pstr_desc = Pstr_attribute _ } :: rest -> iter_on_bs_config_str rest
   | _ :: _ -> ()
 
-let rec iter_on_bs_config_sigi (x : Parsetree.signature) =
+let process_str str =
+  iter_on_bs_config_str str;
+  process_directives str
+
+let rec iter_on_bs_config_sig (x : Parsetree.signature) =
   match x with
   | [] -> ()
   | {
@@ -67,5 +79,7 @@ let rec iter_on_bs_config_sigi (x : Parsetree.signature) =
       Ext_list.iter
         (Ast_payload.ident_or_record_as_config loc payload)
         (Ast_payload.table_dispatch !signature_config_table)
-  | { psig_desc = Psig_attribute _ } :: rest -> iter_on_bs_config_sigi rest
+  | { psig_desc = Psig_attribute _ } :: rest -> iter_on_bs_config_sig rest
   | _ :: _ -> ()
+
+let process_sig s = iter_on_bs_config_sig s

jscomp/frontend/ast_config.mli

@@ -26,6 +26,6 @@ val add_structure : string -> (Parsetree.expression option -> unit) -> unit
 
 val add_signature : string -> (Parsetree.expression option -> unit) -> unit
 
-val iter_on_bs_config_stru : Parsetree.structure -> unit
+val process_str : Parsetree.structure -> unit
 
-val iter_on_bs_config_sigi : Parsetree.signature -> unit
+val process_sig : Parsetree.signature -> unit

jscomp/frontend/bs_builtin_ppx.ml

@@ -431,10 +431,6 @@ let structure_item_mapper (self : mapper) (str : Parsetree.structure_item) :
                   [ { pvb_pat; pvb_expr; pvb_attributes; pvb_loc } ] );
           })
   | Pstr_attribute ({ txt = "bs.config" | "config" }, _) -> str
-  | Pstr_attribute ({ txt = "directive" },
-     PStr [ { pstr_desc = Pstr_eval ({ pexp_desc = Pexp_constant (Pconst_string (d, _)) }, _) } ]) ->
-      Js_config.directives := d :: !Js_config.directives;
-      str
   | _ -> default_mapper.structure_item self str
 
 let local_module_name =

jscomp/frontend/ppx_entry.ml

@@ -26,7 +26,7 @@ let unsafe_mapper = Bs_builtin_ppx.mapper
 
 let rewrite_signature (ast : Parsetree.signature) : Parsetree.signature =
   Bs_ast_invariant.iter_warnings_on_sigi ast;
-  Ast_config.iter_on_bs_config_sigi ast;
+  Ast_config.process_sig ast;
   let ast =
     match !Js_config.jsx_version with
     | None -> ast
@@ -46,7 +46,7 @@ let rewrite_signature (ast : Parsetree.signature) : Parsetree.signature =
 
 let rewrite_implementation (ast : Parsetree.structure) : Parsetree.structure =
   Bs_ast_invariant.iter_warnings_on_stru ast;
-  Ast_config.iter_on_bs_config_stru ast;
+  Ast_config.process_str ast;
   let ast =
     match !Js_config.jsx_version with
     | None -> ast