fix: handle utf8 characters in the dune files(#9728)

boot/libs.ml

@@ -14,6 +14,7 @@ let local_libraries =
   ; ("vendor/fiber/src", Some "Fiber", false, None)
   ; ("src/dune_console", Some "Dune_console", false, None)
   ; ("src/memo", Some "Memo", false, None)
+  ; ("vendor/uutf", None, false, None)
   ; ("src/dune_sexp", Some "Dune_sexp", false, None)
   ; ("src/ocaml-config", Some "Ocaml_config", false, None)
   ; ("src/ocaml", Some "Ocaml", false, None)
@@ -23,7 +24,6 @@ let local_libraries =
   ; ("otherlibs/dune-rpc/private", Some "Dune_rpc_private", false, None)
   ; ("src/dune_config", Some "Dune_config", false, None)
   ; ("vendor/sha", None, false, None)
-  ; ("vendor/uutf", None, false, None)
   ; ("vendor/opam/src/core", None, false, None)
   ; ("vendor/opam-file-format", None, false, None)
   ; ("vendor/opam/src/format", None, false, None)

doc/changes/10113.md

@@ -0,0 +1,2 @@
+- dune file formatting: output utf8 if input is correctly encoded (#10113,
+  fixes #9728, @moyodiallo)

src/dune_sexp/dune

@@ -1,7 +1,7 @@
 (library
  (name dune_sexp)
  (synopsis "[Internal] S-expression library")
- (libraries stdune)
+ (libraries stdune dune_uutf)
  (instrumentation
   (backend bisect_ppx)))
 

src/dune_sexp/escape.ml

@@ -1,26 +1,64 @@
 open! Stdune
 
+(** Note: on OCaml >= 4.14, this can be switched to the following (and the
+    dependency to [Uutf] can be removed)
+
+    {[
+      let next_valid_utf8_length s i =
+        let decode = String.get_utf_8_uchar s i in
+        Option.some_if (Uchar.utf_decode_is_valid decode) (Uchar.utf_decode_length decode)
+      ;;
+    ]} *)
+let next_valid_utf8_uchar_len s i =
+  let pos = ref i in
+  let buf = Bytes.create 1 in
+  let decoder = Uutf.decoder ~encoding:`UTF_8 `Manual in
+  let rec go () =
+    match Uutf.decode decoder with
+    | `Await ->
+      if !pos >= String.length s
+      then None
+      else (
+        Bytes.set buf 0 (String.get s !pos);
+        incr pos;
+        Uutf.Manual.src decoder buf 0 1;
+        go ())
+    | `Uchar _ -> Some (!pos - i)
+    | `Malformed _ -> None
+    | `End -> Code_error.raise "next_valid_utf8_uchar: `End" []
+  in
+  go ()
+;;
+
 let quote_length s =
   let n = ref 0 in
   let len = String.length s in
-  for i = 0 to len - 1 do
-    n
-    := !n
-       +
-       match String.unsafe_get s i with
-       | '\"' | '\\' | '\n' | '\t' | '\r' | '\b' -> 2
-       | '%' -> if i + 1 < len && s.[i + 1] = '{' then 2 else 1
-       | ' ' .. '~' -> 1
-       | _ -> 4
+  let i = ref 0 in
+  while !i < len do
+    (n
+     := !n
+        +
+        match String.unsafe_get s !i with
+        | '\"' | '\\' | '\n' | '\t' | '\r' | '\b' -> 2
+        | '%' -> if !i + 1 < len && s.[!i + 1] = '{' then 2 else 1
+        | ' ' .. '~' -> 1
+        | _ ->
+          (match next_valid_utf8_uchar_len s !i with
+           | Some uchar_len ->
+             i := !i + uchar_len - 1;
+             uchar_len
+           | None -> 4));
+    incr i
   done;
   !n
 ;;
 
 let escape_to s ~dst:s' ~ofs =
   let n = ref ofs in
   let len = String.length s in
-  for i = 0 to len - 1 do
-    (match String.unsafe_get s i with
+  let i = ref 0 in
+  while !i < len do
+    (match String.unsafe_get s !i with
      | ('\"' | '\\') as c ->
        Bytes.unsafe_set s' !n '\\';
        incr n;
@@ -41,21 +79,33 @@ let escape_to s ~dst:s' ~ofs =
        Bytes.unsafe_set s' !n '\\';
        incr n;
        Bytes.unsafe_set s' !n 'b'
-     | '%' when i + 1 < len && s.[i + 1] = '{' ->
+     | '%' when !i + 1 < len && s.[!i + 1] = '{' ->
        Bytes.unsafe_set s' !n '\\';
        incr n;
        Bytes.unsafe_set s' !n '%'
      | ' ' .. '~' as c -> Bytes.unsafe_set s' !n c
      | c ->
-       let a = Char.code c in
-       Bytes.unsafe_set s' !n '\\';
-       incr n;
-       Bytes.unsafe_set s' !n (Char.unsafe_chr (48 + (a / 100)));
-       incr n;
-       Bytes.unsafe_set s' !n (Char.unsafe_chr (48 + (a / 10 mod 10)));
-       incr n;
-       Bytes.unsafe_set s' !n (Char.unsafe_chr (48 + (a mod 10))));
-    incr n
+       (match next_valid_utf8_uchar_len s !i with
+        | Some uchar_len ->
+          Bytes.unsafe_set s' !n (String.unsafe_get s !i);
+          Bytes.unsafe_set s' (!n + 1) (String.unsafe_get s (!i + 1));
+          if uchar_len > 2
+          then Bytes.unsafe_set s' (!n + 2) (String.unsafe_get s (!i + 2));
+          if uchar_len > 3
+          then Bytes.unsafe_set s' (!n + 3) (String.unsafe_get s (!i + 3));
+          n := !n + uchar_len - 1;
+          i := !i + uchar_len - 1
+        | None ->
+          let a = Char.code c in
+          Bytes.unsafe_set s' !n '\\';
+          incr n;
+          Bytes.unsafe_set s' !n (Char.unsafe_chr (48 + (a / 100)));
+          incr n;
+          Bytes.unsafe_set s' !n (Char.unsafe_chr (48 + (a / 10 mod 10)));
+          incr n;
+          Bytes.unsafe_set s' !n (Char.unsafe_chr (48 + (a mod 10)))));
+    incr n;
+    incr i
   done
 ;;
 

test/blackbox-tests/test-cases/formatting/non-ascii-characters.t

@@ -1,13 +1,35 @@
-How the non-ASCII characters are handled, this is also related to the issue #9728
+Utf8 characters are handled for now, this is also related to the issue #9728
 
   $ dune format-dune-file <<EOF
-  > ("É")
+  > ("Éff ĎúÑȨ")
   > EOF
-  ("\195\137")
+  ("Éff ĎúÑȨ")
 
   $ dune format-dune-file <<EOF
   > (run foo %{bin:é})
   > EOF
   File "", line 1, characters 15-16:
   Error: The character '\195' is not allowed inside %{...} forms
   [1]
+
+  $ dune format-dune-file <<EOF
+  > (echo "hÉllo")
+  > EOF
+  (echo "hÉllo")
+
+  $ dune format-dune-file <<EOF
+  > (echo "É")
+  > EOF
+  (echo "É")
+
+  $ dune format-dune-file <<EOF
+  > (Écho "hello")
+  > EOF
+  File "", line 1, characters 1-1:
+  Error: Invalid . file
+  [1]
+
+  $ bash -c "printf '(echo \"%b\")' '\xc0'"| dune format-dune-file
+  (echo "\192")
+  $ bash -c "printf '(echo \"%b\")' '\xf0'"| dune format-dune-file
+  (echo "\240")