[RFC] Lift subdirectory restriction on copy_files stanza?

CHANGES.md

@@ -28,6 +28,10 @@
 - Fix compilation of the module generated for `findlib.dynload`
   (#1317, fix #1310, @diml)
 
+- Lift restriction on `copy_files` and `copy_files#` stanzas that files to be
+  copied should be in a subdirectory of the current directory.
+  (#1323, fix #911, @nojb)
+
 1.2.1 (17/09/2018)
 ------------------
 

src/dune_file.ml

@@ -1808,6 +1808,7 @@ end
 module Copy_files = struct
   type t = { add_line_directive : bool
            ; glob : String_with_vars.t
+           ; syntax_version : Syntax.Version.t
            }
 
   let dparse = String_with_vars.dparse
@@ -1894,11 +1895,13 @@ module Stanzas = struct
       (let%map x = Alias_conf.dparse in
        [Alias x])
     ; "copy_files",
-      (let%map glob = Copy_files.dparse in
-       [Copy_files {add_line_directive = false; glob}])
+      (let%map glob = Copy_files.dparse
+       and syntax_version = Syntax.get_exn Stanza.syntax in
+       [Copy_files {add_line_directive = false; glob; syntax_version}])
     ; "copy_files#",
-      (let%map glob = Copy_files.dparse in
-       [Copy_files {add_line_directive = true; glob}])
+      (let%map glob = Copy_files.dparse
+       and syntax_version = Syntax.get_exn Stanza.syntax in
+       [Copy_files {add_line_directive = true; glob; syntax_version}])
     ; "include",
       (let%map loc = loc
        and fn = relative_file in

src/dune_file.mli

@@ -402,6 +402,7 @@ module Copy_files : sig
   type t =
     { add_line_directive : bool
     ; glob : String_with_vars.t
+    ; syntax_version : Syntax.Version.t
     }
 end
 

src/simple_rules.ml

@@ -66,11 +66,7 @@ let copy_files sctx ~dir ~scope ~src_dir (def: Copy_files.t) =
     let src_glob = SC.expand_vars_string sctx ~dir def.glob ~scope in
     Path.relative src_dir src_glob ~error_loc:loc
   in
-  (* The following condition is required for merlin to work.
-     Additionally, the order in which the rules are evaluated only
-     ensures that [sources_and_targets_known_so_far] returns the
-     right answer for sub-directories only. *)
-  if not (Path.is_descendant glob_in_src ~of_:src_dir) then
+  if def.syntax_version < (1, 3) && not (Path.is_descendant glob_in_src ~of_:src_dir) then
     Errors.fail loc "%s is not a sub-directory of %s"
       (Path.to_string_maybe_quoted glob_in_src) (Path.to_string_maybe_quoted src_dir);
   let glob = Path.basename glob_in_src in

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

@@ -1,4 +1,5 @@
-  $ dune build test.exe .merlin --display short --debug-dependency-path
+  $ dune build --root test1 test.exe .merlin --display short --debug-dependency-path
+  Entering directory 'test1'
       ocamllex lexers/lexer1.ml
       ocamldep .test.eobjs/lexer1.ml.d
       ocamldep .test.eobjs/test.ml.d
@@ -12,7 +13,12 @@
       ocamlopt .test.eobjs/lexer1.{cmx,o}
         ocamlc .test.eobjs/test.{cmi,cmo,cmt}
       ocamlopt .test.eobjs/test.{cmx,o}
-      ocamlopt test.exe
-  $ dune build @bar-source --display short
+      ocamlopt test
+  $ dune build --root test1 @bar-source --display short
+  Entering directory 'test1'
   #line 1 "include/bar.h"
   int foo () {return 42;}
+  $ dune build --root test2 @foo/cat
+  Entering directory 'test2'
+  # 1 "dummy.txt"
+  hello

test/blackbox-tests/test-cases/copy_files/test2/dune

@@ -0,0 +1 @@
+(rule (with-stdout-to dummy.txt (echo "hello")))

test/blackbox-tests/test-cases/copy_files/test2/dune-project

@@ -0,0 +1 @@
+(lang dune 1.3)

test/blackbox-tests/test-cases/copy_files/test2/foo/dune

@@ -0,0 +1,5 @@
+(copy_files# ../dummy.txt)
+
+(alias
+ (name cat)
+ (action (cat %{dep:dummy.txt})))