Fix error when copy_files source does not exist

Closes #1099

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

CHANGES.md

@@ -4,6 +4,9 @@ next
 - Ignore stderr output when trying to find out the number of jobs
   available (#1118, fix #1116, @diml)
 
+- Fix error message when the source directory of `copy_files` does not exist.
+  (#1120, fix #1099, @emillon)
+
 1.1.1 (08/08/2018)
 ------------------
 

src/file_tree.mli

@@ -88,6 +88,9 @@ val files_of : t -> Path.t -> Path.Set.t
 (** [true] iff the path is either a directory or a file *)
 val exists : t -> Path.t -> bool
 
+(** [true] iff the path is a directory *)
+val dir_exists : t -> Path.t -> bool
+
 (** [true] iff the path is a file *)
 val file_exists : t -> Path.t -> string -> bool
 

src/simple_rules.ml

@@ -51,6 +51,12 @@ let copy_files sctx ~dir ~scope ~src_dir (def: Copy_files.t) =
     | Error (_pos, msg) ->
       Loc.fail (String_with_vars.loc def.glob) "invalid glob: %s" msg
   in
+  let file_tree = Super_context.file_tree sctx in
+  if not (File_tree.dir_exists file_tree src_in_src) then
+    Loc.fail
+      loc
+      "cannot find directory: %a"
+      Path.pp src_in_src;
   (* add rules *)
   let src_in_build = Path.append (SC.context sctx).build_dir src_in_src in
   let files = SC.eval_glob sctx ~dir:src_in_build re in

test/blackbox-tests/dune.inc

@@ -231,6 +231,14 @@
    test-cases/github1019
    (progn (run %{exe:cram.exe} -test run.t) (diff? run.t run.t.corrected)))))
 
+(alias
+ (name github1099)
+ (deps (package dune) (source_tree test-cases/github1099))
+ (action
+  (chdir
+   test-cases/github1099
+   (progn (run %{exe:cram.exe} -test run.t) (diff? run.t run.t.corrected)))))
+
 (alias
  (name github20)
  (deps (package dune) (source_tree test-cases/github20))
@@ -803,6 +811,7 @@
   (alias force-test)
   (alias gen-opam-install-file)
   (alias github1019)
+  (alias github1099)
   (alias github20)
   (alias github24)
   (alias github25)
@@ -898,6 +907,7 @@
   (alias findlib-error)
   (alias force-test)
   (alias github1019)
+  (alias github1099)
   (alias github20)
   (alias github24)
   (alias github25)

test/blackbox-tests/test-cases/github1099/file-with-same-name/demo.ml

@@ -0,0 +1 @@
+let () = ()

test/blackbox-tests/test-cases/github1099/file-with-same-name/dune

@@ -0,0 +1,3 @@
+(copy_files# "no_dir/*")
+
+(executable (name demo))

test/blackbox-tests/test-cases/github1099/file-with-same-name/dune-project

@@ -0,0 +1 @@
+(lang dune 1.1)

test/blackbox-tests/test-cases/github1099/no-dir/demo.ml

@@ -0,0 +1 @@
+let () = ()

test/blackbox-tests/test-cases/github1099/no-dir/dune

@@ -0,0 +1,3 @@
+(copy_files# "no_dir/*")
+
+(executable (name demo))

test/blackbox-tests/test-cases/github1099/no-dir/dune-project

@@ -0,0 +1 @@
+(lang dune 1.1)

test/blackbox-tests/test-cases/github1099/run.t

@@ -0,0 +1,15 @@
+If the source directory does not exist, an error message is printed:
+
+  $ dune build --root no-dir demo.exe
+  Entering directory 'no-dir'
+  File "dune", line 1, characters 13-23:
+  Error: cannot find directory: no_dir
+  [1]
+
+This works also is a file exists with the same name:
+
+  $ dune build --root file-with-same-name demo.exe
+  Entering directory 'file-with-same-name'
+  File "dune", line 1, characters 13-23:
+  Error: cannot find directory: no_dir
+  [1]