If a dune file uses OCaml syntax, use ocamlformat

Closes #2012

src/format_rules.ml

@@ -73,10 +73,18 @@ let gen_rules_output sctx (config : Dune_file.Auto_format.t) ~output_dir =
         let exe = resolve_program "refmt" in
         let args = [Arg_spec.Dep input] in
         Some (Build.run ~dir ~stdout_to:output exe args)
-      | "dune", _ when Dune_file.Auto_format.includes config Dune ->
-        let exe = resolve_program "dune" in
-        let args = [Arg_spec.A "format-dune-file"; Dep input] in
-        Some (Build.run ~dir ~stdout_to:output exe args)
+      | "dune", _ ->
+        begin
+          match Format_dune_lang.parse_file (Some file) with
+          | OCaml_syntax _ ->
+            ocaml Impl
+          | Sexps _ when Dune_file.Auto_format.includes config Dune ->
+            let exe = resolve_program "dune" in
+            let args = [Arg_spec.A "format-dune-file"; Dep input] in
+            Some (Build.run ~dir ~stdout_to:output exe args)
+          | Sexps _ ->
+            None
+        end
       | _ -> None
     in
 

test/blackbox-tests/test-cases/formatting/enabled/dune-ocaml-syntax/dune.orig

@@ -0,0 +1,7 @@
+(* -*- tuareg -*- *)
+
+let () = Jbuild_plugin.V1.send {|
+(alias
+ (name runtest)
+ (action (echo "ocaml syntax")))
+|}

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

@@ -1,47 +1,54 @@
 Formatting can be checked using the @fmt target:
 
+  $ cp enabled/dune-ocaml-syntax/dune.orig enabled/dune-ocaml-syntax/dune
   $ cp enabled/ocaml_file.ml.orig enabled/ocaml_file.ml
   $ cp enabled/reason_file.re.orig enabled/reason_file.re
   $ cp enabled/dune.orig enabled/dune
   $ dune build --display short @fmt
       ocamldep fake-tools/.ocamlformat.eobjs/ocamlformat.ml.d
       ocamldep fake-tools/.ocamlformat.eobjs/refmt.ml.d
-        ocamlc fake-tools/.ocamlformat.eobjs/byte/ocamlformat.{cmi,cmo,cmt}
-      ocamlopt fake-tools/.ocamlformat.eobjs/native/ocamlformat.{cmx,o}
-      ocamlopt fake-tools/ocamlformat.exe
-   ocamlformat enabled/.formatted/ocaml_file.ml
-  File "enabled/ocaml_file.ml", line 1, characters 0-0:
-  Files _build/default/enabled/ocaml_file.ml and _build/default/enabled/.formatted/ocaml_file.ml differ.
-          dune enabled/.formatted/dune
-  File "enabled/dune", line 1, characters 0-0:
-  Files _build/default/enabled/dune and _build/default/enabled/.formatted/dune differ.
-          dune enabled/subdir/.formatted/dune
-  File "enabled/subdir/dune", line 1, characters 0-0:
-  Files _build/default/enabled/subdir/dune and _build/default/enabled/subdir/.formatted/dune differ.
         ocamlc fake-tools/.ocamlformat.eobjs/byte/refmt.{cmi,cmo,cmt}
       ocamlopt fake-tools/.ocamlformat.eobjs/native/refmt.{cmx,o}
       ocamlopt fake-tools/refmt.exe
          refmt enabled/.formatted/reason_file.rei
   File "enabled/reason_file.rei", line 1, characters 0-0:
   Files _build/default/enabled/reason_file.rei and _build/default/enabled/.formatted/reason_file.rei differ.
-   ocamlformat enabled/subdir/.formatted/lib.ml
-  File "enabled/subdir/lib.ml", line 1, characters 0-0:
-  Files _build/default/enabled/subdir/lib.ml and _build/default/enabled/subdir/.formatted/lib.ml differ.
-   ocamlformat partial/.formatted/a.ml
-  File "partial/a.ml", line 1, characters 0-0:
-  Files _build/default/partial/a.ml and _build/default/partial/.formatted/a.ml differ.
+          dune enabled/.formatted/dune
+  File "enabled/dune", line 1, characters 0-0:
+  Files _build/default/enabled/dune and _build/default/enabled/.formatted/dune differ.
+          dune enabled/subdir/.formatted/dune
+  File "enabled/subdir/dune", line 1, characters 0-0:
+  Files _build/default/enabled/subdir/dune and _build/default/enabled/subdir/.formatted/dune differ.
+        ocamlc fake-tools/.ocamlformat.eobjs/byte/ocamlformat.{cmi,cmo,cmt}
+      ocamlopt fake-tools/.ocamlformat.eobjs/native/ocamlformat.{cmx,o}
+      ocamlopt fake-tools/ocamlformat.exe
    ocamlformat enabled/.formatted/ocaml_file.mli
   File "enabled/ocaml_file.mli", line 1, characters 0-0:
   Files _build/default/enabled/ocaml_file.mli and _build/default/enabled/.formatted/ocaml_file.mli differ.
          refmt enabled/.formatted/reason_file.re
   File "enabled/reason_file.re", line 1, characters 0-0:
   Files _build/default/enabled/reason_file.re and _build/default/enabled/.formatted/reason_file.re differ.
+   ocamlformat enabled/.formatted/ocaml_file.ml
+  File "enabled/ocaml_file.ml", line 1, characters 0-0:
+  Files _build/default/enabled/ocaml_file.ml and _build/default/enabled/.formatted/ocaml_file.ml differ.
+   ocamlformat enabled/subdir/.formatted/lib.ml
+  File "enabled/subdir/lib.ml", line 1, characters 0-0:
+  Files _build/default/enabled/subdir/lib.ml and _build/default/enabled/subdir/.formatted/lib.ml differ.
+   ocamlformat partial/.formatted/a.ml
+  File "partial/a.ml", line 1, characters 0-0:
+  Files _build/default/partial/a.ml and _build/default/partial/.formatted/a.ml differ.
+   ocamlformat enabled/dune-ocaml-syntax/.formatted/dune
+  File "enabled/dune-ocaml-syntax/dune", line 1, characters 0-0:
+  Files _build/default/enabled/dune-ocaml-syntax/dune and _build/default/enabled/dune-ocaml-syntax/.formatted/dune differ.
   [1]
 
 Configuration files are taken into account for this action:
 
   $ touch enabled/.ocamlformat
   $ dune build --display short @fmt
+   ocamlformat enabled/dune-ocaml-syntax/.formatted/dune
+  File "enabled/dune-ocaml-syntax/dune", line 1, characters 0-0:
+  Files _build/default/enabled/dune-ocaml-syntax/dune and _build/default/enabled/dune-ocaml-syntax/.formatted/dune differ.
          refmt enabled/.formatted/reason_file.re
   File "enabled/reason_file.re", line 1, characters 0-0:
   Files _build/default/enabled/reason_file.re and _build/default/enabled/.formatted/reason_file.re differ.
@@ -88,6 +95,9 @@ All .ocamlformat files are considered dependencies:
 
   $ echo 'margin = 70' > .ocamlformat
   $ dune build --display short @fmt
+   ocamlformat enabled/dune-ocaml-syntax/.formatted/dune
+  File "enabled/dune-ocaml-syntax/dune", line 1, characters 0-0:
+  Files _build/default/enabled/dune-ocaml-syntax/dune and _build/default/enabled/dune-ocaml-syntax/.formatted/dune differ.
          refmt enabled/.formatted/reason_file.re
          refmt enabled/.formatted/reason_file.rei
   File "enabled/reason_file.rei", line 1, characters 0-0: