Allow enabled_if in executable(s) stanza

CHANGES.md

@@ -23,6 +23,9 @@
 - Fix bootstrap on bytecode only switches on windows or where `-j1` is set.
   (#3112, @xclerc, @rgrinberg)
 
+- Allow `enabled_if` fields in `executable(s)` stanzas (#3137,
+  fixes #1690 @voodoos)
+
 2.2.0 (06/02/2020)
 ------------------
 

doc/dune-files.rst

@@ -645,6 +645,8 @@ Executables can also be linked as object or shared object files. See
 
 - ``(optional)`` is the same as the corresponding field of `library`_
 
+- ``(enabled_if <blang expression>)`` is the same as the corresponding field of `library`_
+
 - ``(promote <options>)`` allows promoting the linked executables to
   the source tree. The options are the same as for the :ref:`rule
   promote mode <promote>`. Adding ``(promote (until-clean))`` to an

src/dune/dune_file.ml

@@ -1525,6 +1525,7 @@ module Executables = struct
     ; install_conf : File_binding.Unexpanded.t Install_conf.t option
     ; forbidden_libraries : (Loc.t * Lib_name.t) list
     ; bootstrap_info : string option
+    ; enabled_if : Blang.t
     }
 
   let bootstrap_info_extension =
@@ -1581,6 +1582,7 @@ module Executables = struct
            User_error.raise ~loc
              [ Pp.text "This field is reserved for Dune itself" ];
          fname)
+    and+ enabled_if = enabled_if ~since:(Some (2, 3))
     in
     fun names ~multi ->
       let has_public_name = Names.has_public_name names in
@@ -1621,6 +1623,7 @@ module Executables = struct
       ; install_conf
       ; forbidden_libraries
       ; bootstrap_info
+      ; enabled_if
       }
 
   let single, multi =
@@ -2128,6 +2131,7 @@ module Tests = struct
            ; install_conf = None
            ; forbidden_libraries
            ; bootstrap_info = None
+           ; enabled_if
            }
        ; locks
        ; package

src/dune/dune_file.mli

@@ -296,6 +296,7 @@ module Executables : sig
     ; install_conf : File_binding.Unexpanded.t Install_conf.t option
     ; forbidden_libraries : (Loc.t * Lib_name.t) list
     ; bootstrap_info : string option
+    ; enabled_if : Blang.t
     }
 
   (** Check if the executables have any foreign stubs or archives. *)

src/dune/gen_rules.ml

@@ -83,7 +83,7 @@ end = struct
     | Foreign_library lib ->
       Lib_rules.foreign_rules lib ~sctx ~dir ~dir_contents ~expander;
       empty_none
-    | Executables exes ->
+    | Executables exes when Expander.eval_blang expander exes.enabled_if ->
       Option.iter exes.install_conf ~f:files_to_install;
       let cctx, merlin =
         Exe_rules.rules exes ~sctx ~dir ~scope ~expander ~dir_contents

test/blackbox-tests/dune.inc

@@ -601,6 +601,16 @@
     (run %{exe:cram.exe} run.t -sanitizer %{bin:sanitizer})
     (diff? run.t run.t.corrected)))))
 
+(rule
+ (alias enabled_if-exec)
+ (deps (package dune) (source_tree test-cases/enabled_if-exec))
+ (action
+  (chdir
+   test-cases/enabled_if-exec
+   (progn
+    (run %{exe:cram.exe} run.t -sanitizer %{bin:sanitizer})
+    (diff? run.t run.t.corrected)))))
+
 (rule
  (alias env-env-and-flags-include)
  (deps (package dune) (source_tree test-cases/env/env-and-flags-include))
@@ -2687,6 +2697,7 @@
   (alias duplicate-target-no-loc)
   (alias embed-jbuild)
   (alias enabled_if)
+  (alias enabled_if-exec)
   (alias env-env-and-flags-include)
   (alias env-env-bin-pform)
   (alias env-env-bins)
@@ -2940,6 +2951,7 @@
   (alias duplicate-target-no-loc)
   (alias embed-jbuild)
   (alias enabled_if)
+  (alias enabled_if-exec)
   (alias env-env-and-flags-include)
   (alias env-env-bin-pform)
   (alias env-env-bins)

test/blackbox-tests/test-cases/enabled_if-exec/dis.ml

@@ -0,0 +1 @@
+Printf.eprintf "Ping"

test/blackbox-tests/test-cases/enabled_if-exec/dune

@@ -0,0 +1,9 @@
+(executable
+  (name main)
+  (modules main)
+  (enabled_if true))
+
+(executable
+  (name dis)
+  (modules dis)
+  (enabled_if false))

test/blackbox-tests/test-cases/enabled_if-exec/dune-project

@@ -0,0 +1 @@
+(lang dune 2.3)

test/blackbox-tests/test-cases/enabled_if-exec/main.ml

@@ -0,0 +1 @@
+Printf.eprintf "Pong"

test/blackbox-tests/test-cases/enabled_if-exec/run.t

@@ -0,0 +1,15 @@
+Test that `enabled_if` fields work as expected for executables.
+Since 2.3.
+
+This executable is disabled, any attempt to build it should fail:
+  $ dune build dis.exe
+  Error: Don't know how to build dis.exe
+  [1]
+  $ dune exec ./dis.exe
+  Error: Program "./dis.exe" not found!
+  [1]
+
+This one is enabled
+  $ dune exec ./main.exe
+  Pong
+

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

@@ -19,6 +19,10 @@ This one is enabled:
 
 Test the enabled_if field for libraries:
 
+  $ dune build foo
+  Error: Don't know how to build foo
+  [1]
+
   $ dune build main.exe
   File "dune", line 33, characters 12-15:
   33 |  (libraries foo))