unstable-fmt: ignore files in OCaml syntax (#1784)

* unstable-fmt: ignore files in OCaml syntax

When this is detected, it displays a warning and does nothing.

Signed-off-by: Etienne Millon <me@emillon.org>

CHANGES.md

@@ -110,6 +110,8 @@ unreleased
   stanza. It was previously causing intermediate *mock* files to be
   promoted (#1783, fixes #1781, @diml)
 
+- unstable-fmt: ignore files using OCaml syntax (#1784, @emillon)
+
 1.6.2 (05/12/2018)
 ------------------
 

src/dune_fmt.ml

@@ -1,20 +1,22 @@
 open! Stdune
 open! Import
 
+type dune_file =
+  | OCaml_syntax of Loc.t
+  | Sexps of Dune_lang.Cst.t list
+
+let parse_lexbuf lb =
+  if Dune_lexer.is_script lb then
+    OCaml_syntax (Loc.of_lexbuf lb)
+  else
+    Sexps (Dune_lang.Parser.parse_cst lb)
+
 let parse_file path_opt =
-  let fname, contents =
-    match path_opt with
-    | Some path ->
-      Io.with_file_in path ~f:(fun ic ->
-        let contents = Io.read_all ic in
-        (Path.to_string path, contents)
-      )
-    | None ->
-      let lines = Io.input_lines stdin in
-      let contents = String.concat ~sep:"\n" lines in
-      ("<stdin>", contents)
-  in
-  Dune_lang.parse_cst_string ~fname contents
+  match path_opt with
+  | Some path ->
+    Io.with_lexbuf_from_file path ~f:parse_lexbuf
+  | None ->
+    parse_lexbuf @@ Lexing.from_channel stdin
 
 let can_be_displayed_wrapped =
   List.for_all ~f:(fun (c : Dune_lang.Cst.t) ->
@@ -131,7 +133,9 @@ let format_file ~input ~output =
     Printf.printf
       "Parse error: %s\n"
       (Dune_lang.Parse_error.message e)
-  | sexps ->
+  | OCaml_syntax loc ->
+    Errors.warn loc "OCaml syntax is not supported, skipping."
+  | Sexps sexps ->
     with_output output (fun fmt ->
       pp_top_sexps fmt sexps;
       Format.pp_print_flush fmt ()

src/dune_lang/dune_lang.ml

@@ -361,10 +361,6 @@ let parse_string ~fname ~mode ?lexer str =
   let lb = lexbuf_from_string ~fname str in
   Parser.parse ~mode ?lexer lb
 
-let parse_cst_string ~fname ?lexer str =
-  let lb = lexbuf_from_string ~fname str in
-  Parser.parse_cst ?lexer lb
-
 type dune_lang = t
 
 module Encoder = struct

src/dune_lang/dune_lang.mli

@@ -206,12 +206,6 @@ val parse_string
   -> string
   -> 'a
 
-val parse_cst_string
-  :  fname:string
-  -> ?lexer:Lexer.t
-  -> string
-  -> Cst.t list
-
 module Encoder : sig
   type sexp = t
   include Sexp_intf.Combinators with type 'a t = 'a -> t

test/blackbox-tests/test-cases/fmt/ocaml-syntax.dune

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

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

@@ -164,3 +164,14 @@ When a comment is at the end of a list, the ")" is on a own line.
    ; final unattached
    ; multiline
    )
+
+Files in OCaml syntax are ignored with a warning.
+
+  $ dune unstable-fmt < ocaml-syntax.dune
+  File "", line 1, characters 0-20:
+  Warning: OCaml syntax is not supported, skipping.
+  $ dune unstable-fmt ocaml-syntax.dune
+  File "$TESTCASE_ROOT/ocaml-syntax.dune", line 1, characters 0-20:
+  1 | (* -*- tuareg -*- *)
+      ^^^^^^^^^^^^^^^^^^^^
+  Warning: OCaml syntax is not supported, skipping.