Fix a bug causing all executables to be considered as optional

CHANGES.md

@@ -4,6 +4,8 @@
 - Fix versioning of artifact variables (eg %{cmxa:...}), which were introduced
   in 2.0, not 1.11. (#3149, @nojb)
 
+- Fix a bug causing all executables to be considered as optional (#3163, @diml)
+
 2.3.0 (15/02/2020)
 ------------------
 

src/dune/install_rules.ml

@@ -141,11 +141,14 @@ end = struct
     Option.some_if
       ( match (stanza : Stanza.t) with
       | Dune_file.Library lib ->
-        Lib.DB.available (Scope.libs scope) (Dune_file.Library.best_name lib)
+        (not lib.optional)
+        || Lib.DB.available (Scope.libs scope) (Dune_file.Library.best_name lib)
       | Dune_file.Documentation _
       | Dune_file.Install _ ->
         true
       | Dune_file.Executables ({ install_conf = Some _; _ } as exes) ->
+        (not exes.optional)
+        ||
         let compile_info =
           let dune_version = Scope.project scope |> Dune_project.dune_version in
           Lib.DB.resolve_user_written_deps_for_exes (Scope.libs scope)

test/blackbox-tests/test-cases/optional-executable/run.t

@@ -1,4 +1,23 @@
 Test optional executable
+========================
+
+  $ cat >dune <<EOF
+  > (executable
+  >  (public_name x)
+  >  (libraries does-not-exist)
+  >  (optional))
+  > 
+  > (rule
+  >  (alias run-x)
+  >  (action (run %{exe:x.exe})))
+  > EOF
+
+  $ cat >dune-project <<EOF
+  > (lang dune 2.0)
+  > (package (name x))
+  > EOF
+
+  $ touch x.ml
 
   $ dune build @install
 
@@ -17,3 +36,22 @@ Test optional executable
   Error: Library "does-not-exist" not found.
   Hint: try: dune external-lib-deps --missing @run-x
   [1]
+
+Reproduction case for a bug in dune < 2.4 where all executables where
+considered as optional:
+
+  $ cat >dune <<EOF
+  > (executable
+  >  (public_name x)
+  >  (libraries does-not-exist))
+  > EOF
+
+The following command should fail because the executable is not optional:
+
+  $ dune build @install
+  File "dune", line 3, characters 12-26:
+  3 |  (libraries does-not-exist))
+                  ^^^^^^^^^^^^^^
+  Error: Library "does-not-exist" not found.
+  Hint: try: dune external-lib-deps --missing @install
+  [1]

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

@@ -1,6 +1,25 @@
 Various tests for optional libraries
 ------------------------------------
 
+  $ cat >dune-project <<EOF
+  > (lang dune 1.2)
+  > (name foo)
+  > (package (name foo))
+  > EOF
+
+  $ cat >dune <<EOF
+  > (library
+  >  (name foo)
+  >  (public_name foo)
+  >  (wrapped false)
+  >  (optional)
+  >  (libraries lib_that_doesn't_exist))
+  > EOF
+
+  $ cat >x.ml <<EOF
+  > let x = 42
+  > EOF
+
 Regression test for non-wrapped optional libraries with missing
 dependencies (#1281):
 
@@ -9,3 +28,23 @@ dependencies (#1281):
 Interaction between `@all` and optional libraries:
 
   $ dune build @all
+
+Reproduction case for a bug in dune < 2.4 where all libraries where
+considered as optional:
+
+  $ cat >dune <<EOF
+  > (library
+  >  (name foo)
+  >  (public_name foo)
+  >  (libraries lib_that_doesn't_exist))
+  > EOF
+
+The following command should fail because the executable is not optional:
+
+  $ dune build @install
+  File "dune", line 4, characters 12-34:
+  4 |  (libraries lib_that_doesn't_exist))
+                  ^^^^^^^^^^^^^^^^^^^^^^
+  Error: Library "lib_that_doesn't_exist" not found.
+  Hint: try: dune external-lib-deps --missing @install
+  [1]