Omit dynamic imported module from require, import statement (#6232)

Author: mununki

CHANGELOG.md

@@ -16,6 +16,10 @@
 
 - `-bs-super-errors` flag has been removed along with Super_errors. https://github.com/rescript-lang/rescript-compiler/pull/6199
 
+#### :bug: Bug Fix
+
+- Remove unnecessary require and import statements when using dynamic imports. https://github.com/rescript-lang/rescript-compiler/pull/6232
+
 #### :nail_care: Polish
 
 - In uncurried mode, outcome printer swaps curried and uncurries function printing compared to legacy.

jscomp/core/j.ml

@@ -51,7 +51,7 @@ and ident = Ident.t
     currently we always use quote
 *)
 
-and module_id = { id : ident; kind : Js_op.kind }
+and module_id = { id : ident; kind : Js_op.kind ; dynamic_import : bool }
 
 and required_modules = module_id list
 and vident = Id of ident | Qualified of module_id * string option

jscomp/core/js_dump_program.ml

@@ -73,8 +73,12 @@ let node_program ~output_dir f (x : J.deps_program) =
   P.newline f;
   let cxt =
     Js_dump_import_export.requires L.require Ext_pp_scope.empty f
-      (Ext_list.map x.modules (fun x ->
-           ( x.id,
+      (* Not be emitted in require statements *)
+      (Ext_list.filter_map x.modules (fun x ->
+        match x.dynamic_import with
+        | true -> None
+        | false -> 
+           Some ( x.id,
              Js_name_of_module_id.string_of_module_id x ~output_dir NodeJS,
              is_default x.kind )))
   in
@@ -83,8 +87,12 @@ let node_program ~output_dir f (x : J.deps_program) =
 let es6_program ~output_dir fmt f (x : J.deps_program) =
   let cxt =
     Js_dump_import_export.imports Ext_pp_scope.empty f
-      (Ext_list.map x.modules (fun x ->
-           ( x.id,
+      (* Not be emitted in import statements *)
+      (Ext_list.filter_map x.modules (fun x ->
+        match x.dynamic_import with
+        | true -> None
+        | false -> 
+           Some ( x.id,
              Js_name_of_module_id.string_of_module_id x ~output_dir fmt,
              is_default x.kind )))
   in

jscomp/core/js_exp_make.ml

@@ -76,12 +76,12 @@ let runtime_var_dot ?comment (x : string) (e1 : string) : J.expression =
   {
     expression_desc =
       Var
-        (Qualified ({ id = Ident.create_persistent x; kind = Runtime }, Some e1));
+        (Qualified ({ id = Ident.create_persistent x; kind = Runtime; dynamic_import = false }, Some e1));
     comment;
   }
 
-let ml_var_dot ?comment (id : Ident.t) e : J.expression =
-  { expression_desc = Var (Qualified ({ id; kind = Ml }, Some e)); comment }
+let ml_var_dot ?comment ?(dynamic_import = false) (id : Ident.t) e : J.expression =
+  { expression_desc = Var (Qualified ({ id; kind = Ml; dynamic_import }, Some e)); comment }
 
 (** 
    module as a value 
@@ -93,7 +93,7 @@ let external_var_field ?comment ~external_name:name (id : Ident.t) ~field
     ~default : t =
   {
     expression_desc =
-      Var (Qualified ({ id; kind = External { name; default } }, Some field));
+      Var (Qualified ({ id; kind = External { name; default }; dynamic_import = false }, Some field));
     comment;
   }
 
@@ -102,13 +102,13 @@ let external_var ?comment ~external_name (id : Ident.t) : t =
     expression_desc =
       Var
         (Qualified
-           ( { id; kind = External { name = external_name; default = false } },
+           ( { id; kind = External { name = external_name; default = false }; dynamic_import = false },
              None ));
     comment;
   }
 
-let ml_module_as_var ?comment (id : Ident.t) : t =
-  { expression_desc = Var (Qualified ({ id; kind = Ml }, None)); comment }
+let ml_module_as_var ?comment ?(dynamic_import = false) (id : Ident.t) : t =
+  { expression_desc = Var (Qualified ({ id; kind = Ml; dynamic_import }, None)); comment }
 
 (* Static_index .....................**)
 let runtime_call module_name fn_name args =

jscomp/core/js_exp_make.mli

@@ -49,7 +49,7 @@ val runtime_var_dot : ?comment:string -> string -> string -> t
 
 (* val runtime_var_vid : string -> string -> J.vident *)
 
-val ml_var_dot : ?comment:string -> Ident.t -> string -> t
+val ml_var_dot : ?comment:string -> ?dynamic_import:bool -> Ident.t -> string -> t
 (** [ml_var_dot ocaml_module name]
 *)
 
@@ -66,7 +66,7 @@ val external_var_field :
 
 val external_var : ?comment:string -> external_name:string -> Ident.t -> t
 
-val ml_module_as_var : ?comment:string -> Ident.t -> t
+val ml_module_as_var : ?comment:string -> ?dynamic_import:bool -> Ident.t -> t
 
 val runtime_call :
   string -> (* module_name *)

jscomp/core/js_record_map.ml

@@ -56,9 +56,9 @@ let label : label fn = unknown
 let ident : ident fn = unknown
 
 let module_id : module_id fn =
- fun _self { id = _x0; kind = _x1 } ->
+ fun _self { id = _x0; kind = _x1; dynamic_import = _x2 } ->
   let _x0 = _self.ident _self _x0 in
-  { id = _x0; kind = _x1 }
+  { id = _x0; kind = _x1; dynamic_import = _x2 }
 
 let required_modules : required_modules fn =
  fun _self arg -> list _self.module_id _self arg

jscomp/core/lam.ml

@@ -89,7 +89,7 @@ module Types = struct
 
   and t =
     | Lvar of ident
-    | Lglobal_module of ident
+    | Lglobal_module of ident * bool
     | Lconst of Lam_constant.t
     | Lapply of apply
     | Lfunction of lfunction
@@ -136,7 +136,7 @@ module X = struct
 
   and t = Types.t =
     | Lvar of ident
-    | Lglobal_module of ident
+    | Lglobal_module of ident * bool
     | Lconst of Lam_constant.t
     | Lapply of apply
     | Lfunction of lfunction
@@ -344,8 +344,8 @@ let rec apply fn args (ap_info : ap_info) : t =
 
 let rec eq_approx (l1 : t) (l2 : t) =
   match l1 with
-  | Lglobal_module i1 -> (
-      match l2 with Lglobal_module i2 -> Ident.same i1 i2 | _ -> false)
+  | Lglobal_module (i1, b1) -> (
+      match l2 with Lglobal_module (i2, b2) -> Ident.same i1 i2 && b1 = b2 | _ -> false)
   | Lvar i1 -> ( match l2 with Lvar i2 -> Ident.same i1 i2 | _ -> false)
   | Lconst c1 -> (
       match l2 with Lconst c2 -> Lam_constant.eq_approx c1 c2 | _ -> false)
@@ -434,7 +434,7 @@ let rec seq (a : t) b : t =
   | _ -> Lsequence (a, b)
 
 let var id : t = Lvar id
-let global_module id = Lglobal_module id
+let global_module ?(dynamic_import = false) id = Lglobal_module (id, dynamic_import)
 let const ct : t = Lconst ct
 
 let function_ ~attr ~arity ~params ~body : t =
@@ -574,7 +574,7 @@ let prim ~primitive:(prim : Lam_primitive.t) ~args loc : t =
                 Lprim
                   {
                     primitive = Pfield (pos, Fld_module { name = f1 });
-                    args = [ (Lglobal_module v1 | Lvar v1) ];
+                    args = [ (Lglobal_module (v1, _) | Lvar v1) ];
                   }
                 :: args ) ->
                 pos = i && f = f1 && Ident.same var v1
@@ -586,7 +586,7 @@ let prim ~primitive:(prim : Lam_primitive.t) ~args loc : t =
               Lprim
                 {
                   primitive = Pfield (pos, Fld_module { name = f1 });
-                  args = [ ((Lglobal_module v1 | Lvar v1) as lam) ];
+                  args = [ ((Lglobal_module (v1, _) | Lvar v1) as lam) ];
                 }
               :: args1 ) ->
               if pos = 0 && field1 = f1 && aux rest args1 v1 1 then lam

jscomp/core/lam.mli

@@ -58,7 +58,7 @@ and prim_info = private {
 
 and t = private
   | Lvar of ident
-  | Lglobal_module of ident
+  | Lglobal_module of ident * bool
   | Lconst of Lam_constant.t
   | Lapply of apply
   | Lfunction of lfunction
@@ -98,7 +98,7 @@ val handle_bs_non_obj_ffi :
 val var : ident -> t
 (** Smart constructors *)
 
-val global_module : ident -> t
+val global_module : ?dynamic_import:bool -> ident -> t
 
 val const : Lam_constant.t -> t
 

jscomp/core/lam_arity_analysis.ml

@@ -43,10 +43,10 @@ let rec get_arity (meta : Lam_stats.t) (lam : Lam.t) : Lam_arity.t =
   | Lprim
       {
         primitive = Pfield (_, Fld_module { name });
-        args = [ Lglobal_module id ];
+        args = [ Lglobal_module (id, dynamic_import) ];
         _;
       } -> (
-      match (Lam_compile_env.query_external_id_info id name).arity with
+      match (Lam_compile_env.query_external_id_info ~dynamic_import id name).arity with
       | Single x -> x
       | Submodule _ -> Lam_arity.na)
   | Lprim
@@ -57,12 +57,12 @@ let rec get_arity (meta : Lam_stats.t) (lam : Lam.t) : Lam_arity.t =
             Lprim
               {
                 primitive = Pfield (_, Fld_module { name });
-                args = [ Lglobal_module id ];
+                args = [ Lglobal_module (id, dynamic_import) ];
               };
           ];
         _;
       } -> (
-      match (Lam_compile_env.query_external_id_info id name).arity with
+      match (Lam_compile_env.query_external_id_info ~dynamic_import id name).arity with
       | Submodule subs -> subs.(m) (* TODO: shall we store it as array?*)
       | Single _ -> Lam_arity.na)
   (* TODO: all information except Pccall is complete, we could

jscomp/core/lam_compile.ml

@@ -228,13 +228,13 @@ type initialization = J.block
 let compile output_prefix = 
 
 let rec compile_external_field (* Like [List.empty]*)
-    (lamba_cxt : Lam_compile_context.t) (id : Ident.t) name : Js_output.t =
-  match Lam_compile_env.query_external_id_info id name with
+    ?(dynamic_import = false) (lamba_cxt : Lam_compile_context.t) (id : Ident.t) name : Js_output.t =
+  match Lam_compile_env.query_external_id_info ~dynamic_import id name with
   | { persistent_closed_lambda = Some lam } when Lam_util.not_function lam ->
       compile_lambda lamba_cxt lam
   | _ ->
       Js_output.output_of_expression lamba_cxt.continuation
-        ~no_effects:no_effects_const (E.ml_var_dot id name)
+        ~no_effects:no_effects_const (E.ml_var_dot ~dynamic_import id name)
 (* TODO: how nested module call would behave,
    In the future, we should keep in track  of if
    it is fully applied from [Lapply]
@@ -263,10 +263,10 @@ let rec compile_external_field (* Like [List.empty]*)
     for the function, generative module or functor can be a function,
     however it can not be global -- global can only module
 *)
-and compile_external_field_apply (appinfo : Lam.apply) (module_id : Ident.t)
+and compile_external_field_apply ?(dynamic_import = false) (appinfo : Lam.apply) (module_id : Ident.t)
     (field_name : string) (lambda_cxt : Lam_compile_context.t) : Js_output.t =
   let ident_info =
-    Lam_compile_env.query_external_id_info module_id field_name
+    Lam_compile_env.query_external_id_info ~dynamic_import module_id field_name
   in
   let ap_args = appinfo.ap_args in
   match ident_info.persistent_closed_lambda with
@@ -292,7 +292,7 @@ and compile_external_field_apply (appinfo : Lam.apply) (module_id : Ident.t)
               | _ -> assert false)
       in
 
-      let fn = E.ml_var_dot module_id ident_info.name in
+      let fn = E.ml_var_dot ~dynamic_import module_id ident_info.name in
       let expression =
         match appinfo.ap_info.ap_status with
         | (App_infer_full | App_uncurry) as ap_status ->
@@ -1410,11 +1410,11 @@ and compile_apply (appinfo : Lam.apply) (lambda_cxt : Lam_compile_context.t) =
   (* External function call: it can not be tailcall in this case*)
   | {
    ap_func =
-     Lprim { primitive = Pfield (_, fld_info); args = [ Lglobal_module id ]; _ };
+     Lprim { primitive = Pfield (_, fld_info); args = [ Lglobal_module (id, dynamic_import) ]; _ };
   } -> (
       match fld_info with
       | Fld_module { name } ->
-          compile_external_field_apply appinfo id name lambda_cxt
+          compile_external_field_apply ~dynamic_import appinfo id name lambda_cxt
       | _ -> assert false)
   | _ -> (
       (* TODO: ---
@@ -1491,11 +1491,11 @@ and compile_apply (appinfo : Lam.apply) (lambda_cxt : Lam_compile_context.t) =
 and compile_prim (prim_info : Lam.prim_info)
     (lambda_cxt : Lam_compile_context.t) =
   match prim_info with
-  | { primitive = Pfield (_, fld_info); args = [ Lglobal_module id ]; _ } -> (
+  | { primitive = Pfield (_, fld_info); args = [ Lglobal_module (id, dynamic_import) ]; _ } -> (
       (* should be before Lglobal_global *)
       match fld_info with
       | Fld_module { name = field } ->
-          compile_external_field lambda_cxt id field
+          compile_external_field ~dynamic_import lambda_cxt id field
       | _ -> assert false)
   | { primitive = Praise; args = [ e ]; _ } -> (
       match
@@ -1715,13 +1715,13 @@ and compile_lambda (lambda_cxt : Lam_compile_context.t) (cur_lam : Lam.t) :
       Js_output.output_of_expression lambda_cxt.continuation
         ~no_effects:no_effects_const
         (Lam_compile_const.translate c)
-  | Lglobal_module i ->
+  | Lglobal_module (i, dynamic_import) ->
       (* introduced by
          1. {[ include Array --> let include  = Array  ]}
          2. inline functor application
       *)
       Js_output.output_of_block_and_expression lambda_cxt.continuation []
-        (E.ml_module_as_var i)
+        (E.ml_module_as_var ~dynamic_import i)
   | Lprim prim_info -> compile_prim prim_info lambda_cxt
   | Lsequence (l1, l2) ->
       let output_l1 =
@@ -1759,4 +1759,4 @@ and compile_lambda (lambda_cxt : Lam_compile_context.t) (cur_lam : Lam.t) :
 in compile_recursive_lets, compile_lambda
 
 let compile_recursive_lets ~output_prefix = fst (compile output_prefix)
-let compile_lambda ~output_prefix = snd (compile output_prefix)
+let compile_lambda ~output_prefix = snd (compile output_prefix)