Jsoo: make dune aware of sourcemap generation (ocaml#10777)

* Jsoo: new test case for jsoo
* Jsoo: make dune aware of sourcemap
* fix parsing of sourcemap

Signed-off-by: Hugo Heuzard <hugo.heuzard@gmail.com>

doc/changes/10777.md

@@ -0,0 +1,5 @@
+- New option to control jsoo sourcemap generation in env and executable stanza
+  (@hhugo, #10777)
+
+- One can now control jsoo compilation_mode inside an executable stanza
+  (@hhugo, #10777)

doc/jsoo.rst

@@ -18,7 +18,7 @@ translating OCaml bytecode to JS files. The compiler can be installed with opam:
 Compiling to JS
 ===============
 
-Dune has full support building Js_of_ocaml libraries and executables transparently.
+Dune has full support building js_of_ocaml libraries and executables transparently.
 There's no need to customize or enable anything to compile OCaml
 libraries/executables to JS.
 
@@ -46,7 +46,7 @@ And then request the ``.js`` target:
 Similar targets are created for libraries, but we recommend sticking to the
 executable targets.
 
-If you're using the Js_of_ocaml syntax extension, you must remember to add the
+If you're using the js_of_ocaml syntax extension, you must remember to add the
 appropriate PPX in the ``preprocess`` field:
 
 .. code:: dune
@@ -62,7 +62,7 @@ Separate Compilation
 Dune supports two modes of compilation:
 
 - Direct compilation of a bytecode program to JavaScript. This mode allows
-  Js_of_ocaml to perform whole-program deadcode elimination and whole-program
+  js_of_ocaml to perform whole-program deadcode elimination and whole-program
   inlining.
 
 - Separate compilation, where compilation units are compiled to JavaScript
@@ -71,7 +71,16 @@ Dune supports two modes of compilation:
 
 The separate compilation mode will be selected when the build profile
 is ``dev``, which is the default. It can also be explicitly specified
-in an ``env`` stanza. See :doc:`/reference/dune/env` for more
-information.
+in an ``env`` stanza (see :doc:`/reference/dune/env`) or per executable
+inside ``(js_of_ocaml (compilation_mode ...))`` (see :doc:`/reference/dune/executable`)
+
+Sourcemap
+=========
+
+Js_of_ocaml can generate sourcemap for the generated JavaScript file.
+It can either embed it at the end of the ``.js`` file or write it to separate file.
+By default, it is inlined when using the ``dev`` build profile and is not generated otherwise.
+The behavior can explicitly be specified in an ``env`` stanza (see :doc:`/reference/dune/env`)
+or per executable inside ``(js_of_ocaml (sourcemap ...))`` (see :doc:`/reference/dune/executable`)
 
 .. _js_of_ocaml: http://ocsigen.org/js_of_ocaml/

doc/reference/dune/env.rst

@@ -45,6 +45,9 @@ Fields supported in ``<settings>`` are:
   compilation or not where ``<mode>`` is either ``whole_program`` or
   ``separate``.
 
+- ``(js_of_ocaml (sourcemap <mode>))`` controls whether to generate sourcemap
+  or not where ``<mode>`` is either ``no``, ``file`` (to generate sourcemap in a ``.map`` file next the the generated javascript file) or ``inline`` (to inline the sourcemap at the end of the generated JavaScript file).
+
 - ``(js_of_ocaml (runtest_alias <alias-name>))`` specifies the alias under which
   :ref:`inline_tests` and tests (:ref:`tests-stanza`) run for the `js` mode.
 

doc/reference/dune/executable.rst

@@ -242,7 +242,7 @@ contains C stubs you may want to use ``(modes exe)``.
 js_of_ocaml
 ~~~~~~~~~~~
 
-In ``library`` and ``executables`` stanzas, you can specify ``js_of_ocaml``
+In ``library`` and ``executable`` stanzas, you can specify ``js_of_ocaml``
 options using ``(js_of_ocaml (<js_of_ocaml-options>))``.
 
 ``<js_of_ocaml-options>`` are all optional:
@@ -259,10 +259,16 @@ options using ``(js_of_ocaml (<js_of_ocaml-options>))``.
 - ``(javascript_files (<files-list>))`` to specify ``js_of_ocaml`` JavaScript
   runtime files.
 
+- ``(compilation_mode <mode>)`` where ``<mode>>`` is either ``whole_program`` or ``separate``.
+  This is only available inside ``executable`` stanzas.
+
+- ``(sourcemap <config>)`` where ``<config>>`` is one of ``no``, ``file`` or ``inline``.
+  This is only available inside ``executable`` stanzas.
+
 ``<flags>`` is specified in the :doc:`/reference/ordered-set-language`.
 
-The default value for ``(flags ...)`` depends on the selected build profile. The
-build profile ``dev`` (the default) will enable sourcemap and the pretty
+The default values for ``flags``, ``compilation_mode`` and ``sourcemap`` depend on the selected build profile. The
+build profile ``dev`` (the default) will enable inline sourcemap, separate compilation and pretty
 JavaScript output.
 
 See :ref:`jsoo` for more information.

src/dune_rules/jsoo/js_of_ocaml.ml

@@ -12,6 +12,23 @@ end
 
 let field_oslu name = Ordered_set_lang.Unexpanded.field name
 
+module Sourcemap = struct
+  type t =
+    | No
+    | Inline
+    | File
+
+  let decode = enum [ "no", No; "inline", Inline; "file", File ]
+
+  let equal x y =
+    match x, y with
+    | No, No -> true
+    | Inline, Inline -> true
+    | File, File -> true
+    | No, _ | Inline, _ | File, _ -> false
+  ;;
+end
+
 module Flags = struct
   type 'flags t =
     { build_runtime : 'flags
@@ -38,11 +55,7 @@ module Flags = struct
 
   let default ~profile =
     if Profile.is_dev profile
-    then
-      { build_runtime = [ "--pretty"; "--source-map-inline" ]
-      ; compile = [ "--pretty"; "--source-map-inline" ]
-      ; link = [ "--source-map-inline" ]
-      }
+    then { build_runtime = [ "--pretty" ]; compile = [ "--pretty" ]; link = [] }
     else empty
   ;;
 
@@ -87,13 +100,31 @@ module Flags = struct
   ;;
 end
 
+module Compilation_mode = struct
+  type t =
+    | Whole_program
+    | Separate_compilation
+
+  let decode = enum [ "whole_program", Whole_program; "separate", Separate_compilation ]
+
+  let equal x y =
+    match x, y with
+    | Separate_compilation, Separate_compilation -> true
+    | Whole_program, Whole_program -> true
+    | Separate_compilation, _ -> false
+    | Whole_program, _ -> false
+  ;;
+end
+
 module In_buildable = struct
   type t =
     { flags : Ordered_set_lang.Unexpanded.t Flags.t
     ; javascript_files : string list
+    ; compilation_mode : Compilation_mode.t option
+    ; sourcemap : Sourcemap.t option
     }
 
-  let decode =
+  let decode ~executable =
     let* syntax_version = Dune_lang.Syntax.get_exn Stanza.syntax in
     if syntax_version < (3, 0)
     then
@@ -106,78 +137,111 @@ module In_buildable = struct
              ; link = flags (* we set link as well to preserve the old semantic *)
              }
          ; javascript_files
+         ; compilation_mode = None
+         ; sourcemap = None
          })
     else
       fields
         (let+ flags = Flags.decode
-         and+ javascript_files = field "javascript_files" (repeat string) ~default:[] in
-         { flags; javascript_files })
+         and+ javascript_files = field "javascript_files" (repeat string) ~default:[]
+         and+ compilation_mode =
+           if executable
+           then
+             field_o
+               "compilation_mode"
+               (Dune_lang.Syntax.since Stanza.syntax (3, 17) >>> Compilation_mode.decode)
+           else return None
+         and+ sourcemap =
+           if executable
+           then
+             field_o
+               "sourcemap"
+               (Dune_lang.Syntax.since Stanza.syntax (3, 17) >>> Sourcemap.decode)
+           else return None
+         in
+         { flags; javascript_files; compilation_mode; sourcemap })
   ;;
 
-  let default = { flags = Flags.standard; javascript_files = [] }
+  let default =
+    { flags = Flags.standard
+    ; javascript_files = []
+    ; compilation_mode = None
+    ; sourcemap = None
+    }
+  ;;
 end
 
 module In_context = struct
   type t =
     { flags : Ordered_set_lang.Unexpanded.t Flags.t
     ; javascript_files : Path.Build.t list
+    ; compilation_mode : Compilation_mode.t option
+    ; sourcemap : Sourcemap.t option
     }
 
   let make ~(dir : Path.Build.t) (x : In_buildable.t) =
     { flags = x.flags
     ; javascript_files =
         List.map ~f:(fun name -> Path.Build.relative dir name) x.javascript_files
+    ; compilation_mode = x.compilation_mode
+    ; sourcemap = x.sourcemap
     }
   ;;
 
-  let default = { flags = Flags.standard; javascript_files = [] }
-end
-
-module Compilation_mode = struct
-  type t =
-    | Whole_program
-    | Separate_compilation
-
-  let decode = enum [ "whole_program", Whole_program; "separate", Separate_compilation ]
-
-  let equal x y =
-    match x, y with
-    | Separate_compilation, Separate_compilation -> true
-    | Whole_program, Whole_program -> true
-    | Separate_compilation, _ -> false
-    | Whole_program, _ -> false
+  let default =
+    { flags = Flags.standard
+    ; javascript_files = []
+    ; compilation_mode = None
+    ; sourcemap = None
+    }
   ;;
 end
 
 module Env = struct
   type 'a t =
     { compilation_mode : Compilation_mode.t option
+    ; sourcemap : Sourcemap.t option
     ; runtest_alias : Alias.Name.t option
     ; flags : 'a Flags.t
     }
 
   let decode =
     fields
     @@ let+ compilation_mode = field_o "compilation_mode" Compilation_mode.decode
+       and+ sourcemap =
+         field_o
+           "sourcemap"
+           (Dune_lang.Syntax.since Stanza.syntax (3, 17) >>> Sourcemap.decode)
        and+ runtest_alias = field_o "runtest_alias" Dune_lang.Alias.decode
        and+ flags = Flags.decode in
        Option.iter ~f:Alias.register_as_standard runtest_alias;
-       { compilation_mode; runtest_alias; flags }
+       { compilation_mode; sourcemap; runtest_alias; flags }
   ;;
 
-  let equal { compilation_mode; runtest_alias; flags } t =
+  let equal { compilation_mode; sourcemap; runtest_alias; flags } t =
     Option.equal Compilation_mode.equal compilation_mode t.compilation_mode
+    && Option.equal Sourcemap.equal sourcemap t.sourcemap
     && Option.equal Alias.Name.equal runtest_alias t.runtest_alias
     && Flags.equal Ordered_set_lang.Unexpanded.equal flags t.flags
   ;;
 
-  let map ~f { compilation_mode; runtest_alias; flags } =
-    { compilation_mode; runtest_alias; flags = Flags.map ~f flags }
+  let map ~f { compilation_mode; sourcemap; runtest_alias; flags } =
+    { compilation_mode; sourcemap; runtest_alias; flags = Flags.map ~f flags }
   ;;
 
-  let empty = { compilation_mode = None; runtest_alias = None; flags = Flags.standard }
+  let empty =
+    { compilation_mode = None
+    ; sourcemap = None
+    ; runtest_alias = None
+    ; flags = Flags.standard
+    }
+  ;;
 
   let default ~profile =
-    { compilation_mode = None; runtest_alias = None; flags = Flags.default ~profile }
+    { compilation_mode = None
+    ; sourcemap = None
+    ; runtest_alias = None
+    ; flags = Flags.default ~profile
+    }
   ;;
 end

src/dune_rules/jsoo/js_of_ocaml.mli

@@ -38,35 +38,47 @@ module Flags : sig
   val dump : string list Action_builder.t t -> Dune_lang.t list Action_builder.t
 end
 
+module Sourcemap : sig
+  type t =
+    | No
+    | Inline
+    | File
+end
+
+module Compilation_mode : sig
+  type t =
+    | Whole_program
+    | Separate_compilation
+end
+
 module In_buildable : sig
   type t =
     { flags : Flags.Spec.t
     ; javascript_files : string list
+    ; compilation_mode : Compilation_mode.t option
+    ; sourcemap : Sourcemap.t option
     }
 
-  val decode : t Dune_lang.Decoder.t
+  val decode : executable:bool -> t Dune_lang.Decoder.t
   val default : t
 end
 
 module In_context : sig
   type t =
     { flags : Flags.Spec.t
     ; javascript_files : Path.Build.t list
+    ; compilation_mode : Compilation_mode.t option
+    ; sourcemap : Sourcemap.t option
     }
 
   val make : dir:Path.Build.t -> In_buildable.t -> t
   val default : t
 end
 
-module Compilation_mode : sig
-  type t =
-    | Whole_program
-    | Separate_compilation
-end
-
 module Env : sig
   type 'a t =
     { compilation_mode : Compilation_mode.t option
+    ; sourcemap : Sourcemap.t option
     ; runtest_alias : Alias.Name.t option
     ; flags : 'a Flags.t
     }