Improve generated dune-project template

Signed-off-by: Rudi Grinberg <rudi.grinberg@gmail.com>

src/dune_project.ml

@@ -236,7 +236,12 @@ module Project_file_edit = struct
     else begin
       let ver = !default_dune_language_version in
       let lines =
-        [sprintf "(lang dune %s)" (Syntax.Version.to_string ver)]
+        [ sprintf "(lang dune %s)" (Syntax.Version.to_string ver)
+        ; sprintf ";; (explicit_js_mode) ;; uncomment to only enable js \
+                  targets with (modes js)"
+        ; sprintf ";; (implicit_transitive_deps false) ;; uncomment to \
+                   disallow transitive deps"
+        ]
       in
       let lines =
         match t.project_name with

test/blackbox-tests/test-cases/dune-init/run.t

@@ -11,6 +11,8 @@ Can build the public library
   $ cd _test_lib_dir && touch test_lib.opam && dune build
   Info: creating file dune-project with this contents:
   | (lang dune 1.9)
+  | ;; (explicit_js_mode) ;; uncomment to only enable js targets with (modes js)
+  | ;; (implicit_transitive_deps false) ;; uncomment to disallow transitive deps
   | (name test_lib)
 
   $ cat ./_test_lib_dir/dune
@@ -63,6 +65,8 @@ Can build an executable
   $ cd _test_bin_dir && touch test_bin.opam && dune build
   Info: creating file dune-project with this contents:
   | (lang dune 1.9)
+  | ;; (explicit_js_mode) ;; uncomment to only enable js targets with (modes js)
+  | ;; (implicit_transitive_deps false) ;; uncomment to disallow transitive deps
   | (name test_bin)
 
 
@@ -144,6 +148,8 @@ Can build the combo project
   $ cd _test_lib_exe_dir && touch test_bin.opam && dune build
   Info: creating file dune-project with this contents:
   | (lang dune 1.9)
+  | ;; (explicit_js_mode) ;; uncomment to only enable js targets with (modes js)
+  | ;; (implicit_transitive_deps false) ;; uncomment to disallow transitive deps
   | (name test_bin)
 
 
@@ -179,6 +185,8 @@ Can build the multiple library project
   $ cd _test_lib && touch test_lib1.opam && dune build
   Info: creating file dune-project with this contents:
   | (lang dune 1.9)
+  | ;; (explicit_js_mode) ;; uncomment to only enable js targets with (modes js)
+  | ;; (implicit_transitive_deps false) ;; uncomment to disallow transitive deps
   | (name test_lib1)
 
 

test/blackbox-tests/test-cases/dune-project-edition/run.t

@@ -5,9 +5,13 @@
   $ dune build
   Info: creating file dune-project with this contents:
   | (lang dune 1.9)
+  | ;; (explicit_js_mode) ;; uncomment to only enable js targets with (modes js)
+  | ;; (implicit_transitive_deps false) ;; uncomment to disallow transitive deps
 
   $ cat dune-project
   (lang dune 1.9)
+  ;; (explicit_js_mode) ;; uncomment to only enable js targets with (modes js)
+  ;; (implicit_transitive_deps false) ;; uncomment to disallow transitive deps
 
 Test that using menhir automatically update the dune-project file
 
@@ -16,4 +20,6 @@ Test that using menhir automatically update the dune-project file
   Info: appending this line to dune-project: (using menhir 2.0)
   $ cat dune-project
   (lang dune 1.9)
+  ;; (explicit_js_mode) ;; uncomment to only enable js targets with (modes js)
+  ;; (implicit_transitive_deps false) ;; uncomment to disallow transitive deps
   (using menhir 2.0)

test/blackbox-tests/test-cases/github1529/run.t

@@ -4,5 +4,7 @@ file is present.
   $ dune build
   Info: creating file dune-project with this contents:
   | (lang dune 1.9)
+  | ;; (explicit_js_mode) ;; uncomment to only enable js targets with (modes js)
+  | ;; (implicit_transitive_deps false) ;; uncomment to disallow transitive deps
 
   Info: appending this line to dune-project: (using menhir 2.0)

test/blackbox-tests/test-cases/upgrader/run.t

@@ -1,6 +1,8 @@
   $ dune upgrade
   Info: creating file dune-project with this contents:
   | (lang dune 1.0)
+  | ;; (explicit_js_mode) ;; uncomment to only enable js targets with (modes js)
+  | ;; (implicit_transitive_deps false) ;; uncomment to disallow transitive deps
   | (name foo)
 
   Upgrading foo.opam...