don't add rules if lib stanza is disabled

Signed-off-by: Javier Chávarri <javier.chavarri@gmail.com>

src/dune_rules/gen_rules.ml

@@ -112,8 +112,11 @@ end = struct
       let+ () = toplevel_setup ~sctx ~dir ~toplevel in
       empty_none
     | Library.T lib ->
-      let* cctx, merlin = Lib_rules.rules lib ~sctx ~dir ~scope ~dir_contents ~expander in
-      Memo.return { empty_none with merlin; cctx = Some (lib.buildable.loc, cctx) }
+      let* available = Lib_rules.rules lib ~sctx ~dir ~scope ~dir_contents ~expander in
+      (match available with
+       | None -> Memo.return empty_none
+       | Some (cctx, merlin) ->
+         Memo.return { empty_none with merlin; cctx = Some (lib.buildable.loc, cctx) })
     | Foreign.Library.T lib ->
       Expander.eval_blang expander lib.enabled_if
       >>= if_available (fun () ->

src/dune_rules/lib.ml

@@ -1993,7 +1993,7 @@ module DB = struct
 
   let get_compile_info t ~allow_overlaps ~dir name =
     let open Memo.O in
-    find_even_when_hidden t name
+    find t name
     >>| function
     | Some lib ->
       (match Local.of_lib lib with
@@ -2003,15 +2003,9 @@ module DB = struct
            [ "name", Lib_name.to_dyn name ]
        | Some info ->
          (match Path.Build.equal dir (Lib_info.src_dir (Local.info info)) with
-          | true -> lib, Compile.for_lib ~allow_overlaps t lib
-          | false ->
-            Code_error.raise
-              "Lib.DB.get_compile_info got library that doesn't match build dir"
-              [ "name", Lib_name.to_dyn name; "dir", Path.Build.to_dyn dir ]))
-    | None ->
-      Code_error.raise
-        "Lib.DB.get_compile_info got library that doesn't exist"
-        [ "name", Lib_name.to_dyn name ]
+          | true -> Some (lib, Compile.for_lib ~allow_overlaps t lib)
+          | false -> None))
+    | None -> None
   ;;
 
   let resolve_user_written_deps

src/dune_rules/lib.mli

@@ -141,7 +141,7 @@ module DB : sig
     -> allow_overlaps:bool
     -> dir:Path.Build.t
     -> Lib_name.t
-    -> (lib * Compile.t) Memo.t
+    -> (lib * Compile.t) option Memo.t
 
   val resolve : t -> Loc.t * Lib_name.t -> lib Resolve.Memo.t
 

src/dune_rules/lib_rules.ml

@@ -642,35 +642,41 @@ let library_rules
 
 let rules (lib : Library.t) ~sctx ~dir_contents ~dir ~expander ~scope =
   let buildable = lib.buildable in
-  let* local_lib, compile_info =
+  let* available =
     Lib.DB.get_compile_info
       (Scope.libs scope)
       (Library.best_name lib)
       ~allow_overlaps:buildable.allow_overlapping_dependencies
       ~dir
   in
-  let local_lib = Lib.Local.of_lib_exn local_lib in
-  let f () =
-    let* source_modules =
-      Dir_contents.ocaml dir_contents
-      >>| Ml_sources.modules ~for_:(Library (Library.best_name lib))
+  match available with
+  | None -> Memo.return None
+  | Some (local_lib, compile_info) ->
+    let local_lib = Lib.Local.of_lib_exn local_lib in
+    let f () =
+      let* source_modules =
+        Dir_contents.ocaml dir_contents
+        >>| Ml_sources.modules ~for_:(Library (Library.best_name lib))
+      in
+      let* cctx = cctx lib ~sctx ~source_modules ~dir ~scope ~expander ~compile_info in
+      let* () =
+        match buildable.ctypes with
+        | None -> Memo.return ()
+        | Some _ ->
+          Ctypes_rules.gen_rules ~loc:(fst lib.name) ~cctx ~buildable ~sctx ~scope ~dir
+      in
+      library_rules
+        lib
+        ~local_lib
+        ~cctx
+        ~source_modules
+        ~dir_contents
+        ~compile_info
+        ~ctx_dir:dir
     in
-    let* cctx = cctx lib ~sctx ~source_modules ~dir ~scope ~expander ~compile_info in
-    let* () =
-      match buildable.ctypes with
-      | None -> Memo.return ()
-      | Some _ ->
-        Ctypes_rules.gen_rules ~loc:(fst lib.name) ~cctx ~buildable ~sctx ~scope ~dir
+    let* () = Buildable_rules.gen_select_rules sctx compile_info ~dir in
+    let* res =
+      Buildable_rules.with_lib_deps (Super_context.context sctx) compile_info ~dir ~f
     in
-    library_rules
-      lib
-      ~local_lib
-      ~cctx
-      ~source_modules
-      ~dir_contents
-      ~compile_info
-      ~ctx_dir:dir
-  in
-  let* () = Buildable_rules.gen_select_rules sctx compile_info ~dir in
-  Buildable_rules.with_lib_deps (Super_context.context sctx) compile_info ~dir ~f
+    Memo.return (Some res)
 ;;

src/dune_rules/lib_rules.mli

@@ -15,4 +15,4 @@ val rules
   -> dir:Path.Build.t
   -> expander:Expander.t
   -> scope:Scope.t
-  -> (Compilation_context.t * Merlin.t option) Memo.t
+  -> (Compilation_context.t * Merlin.t option) option Memo.t

src/dune_rules/top_module.ml

@@ -43,29 +43,32 @@ let find_module sctx src =
      | Some stanza ->
        let* scope = Scope.DB.find_by_dir dir in
        let* expander = Super_context.expander sctx ~dir in
-       let+ cctx, merlin =
+       let* available =
          drop_rules
          @@ fun () ->
          match stanza with
          | `Executables exes ->
            let* cctx, merlin =
              Exe_rules.rules ~sctx ~dir ~dir_contents ~scope ~expander exes
            in
-           Memo.return (cctx, Some merlin)
+           Memo.return (Some (cctx, Some merlin))
          | `Library lib -> Lib_rules.rules lib ~sctx ~dir ~scope ~dir_contents ~expander
        in
-       let modules = Compilation_context.modules cctx in
-       let module_ =
-         match Modules.find modules module_name with
-         | Some m -> m
-         | None ->
-           User_error.raise
-             [ Pp.textf
-                 "Could not find module corresponding to source file %s"
-                 (Path.Build.to_string_maybe_quoted src)
-             ]
-       in
-       Some (module_, cctx, merlin))
+       (match available with
+        | None -> Memo.return None
+        | Some (cctx, merlin) ->
+          let modules = Compilation_context.modules cctx in
+          let module_ =
+            match Modules.find modules module_name with
+            | Some m -> m
+            | None ->
+              User_error.raise
+                [ Pp.textf
+                    "Could not find module corresponding to source file %s"
+                    (Path.Build.to_string_maybe_quoted src)
+                ]
+          in
+          Memo.return (Some (module_, cctx, merlin))))
 ;;
 
 let module_deps cctx module_ =

test/blackbox-tests/test-cases/enabled_if/eif-library-cmo-disabled.t

@@ -0,0 +1,32 @@
+Test behavior when targeting artifacts of a disabled library
+
+  $ mkdir -p a b
+  $ cat > dune-project << EOF
+  > (lang dune 3.13)
+  > EOF
+  $ cat > dune << EOF
+  > (library
+  >  (name foo)
+  >  (enabled_if false))
+  > EOF
+  $ cat > foo.ml <<EOF
+  > let x = "foo"
+  > EOF
+  $ dune build %{cmo:foo} --display=verbose
+  Shared cache: disabled
+  Shared cache location: /home/me/.cache/dune/db
+  Workspace root:
+  $TESTCASE_ROOT
+  Dune context:
+   { name = "default"
+   ; kind = "default"
+   ; profile = Dev
+   ; merlin = true
+   ; fdo_target_exe = None
+   ; build_dir = In_build_dir "default"
+   ; installed_env = map {}
+   ; instrument_with = []
+   }
+  File "command line", line 1, characters 0-10:
+  Error: Module Foo does not exist.
+  [1]

test/blackbox-tests/test-cases/enabled_if/eif-library-name-collision-same-folder.t

@@ -28,7 +28,17 @@ is not possible at the moment
   > let x = "foo"
   > EOF
 
-  $ dune build
+  $ dune build --display=short
+        ocamlc .foo.objs/byte/foo.{cmi,cmo,cmt} [alt-context]
+        ocamlc .foo.objs/byte/foo.{cmi,cmo,cmt}
+      ocamlopt .foo.objs/native/foo.{cmx,o} [alt-context]
+        ocamlc foo.cma [alt-context]
+      ocamlopt .foo.objs/native/foo.{cmx,o}
+        ocamlc foo.cma
+      ocamlopt foo.{a,cmxa} [alt-context]
+      ocamlopt foo.{a,cmxa}
+      ocamlopt foo.cmxs [alt-context]
+      ocamlopt foo.cmxs
 
 For public libraries
 
@@ -62,48 +72,6 @@ In the same context
 If no public lib is available, the build finishes fine as there are no consumers of the libraries
 
   $ dune build
-  Internal error, please report upstream including the contents of _build/log.
-  Description:
-    ("Lib.DB.get_compile_info got library that doesn't exist",
-    { name = "foo" })
-  Raised at Stdune__Code_error.raise in file
-    "otherlibs/stdune/src/code_error.ml", line 10, characters 30-62
-  Called from Fiber__Core.O.(>>|).(fun) in file "vendor/fiber/src/core.ml",
-    line 253, characters 36-41
-  Called from Fiber__Core.apply2 in file "vendor/fiber/src/core.ml", line 92,
-    characters 6-11
-  Re-raised at Stdune__Exn.raise_with_backtrace in file
-    "otherlibs/stdune/src/exn.ml", line 38, characters 27-56
-  Called from Fiber__Scheduler.exec in file "vendor/fiber/src/scheduler.ml",
-    line 76, characters 8-11
-  Re-raised at Stdune__Exn.raise_with_backtrace in file
-    "otherlibs/stdune/src/exn.ml", line 38, characters 27-56
-  Called from Fiber__Scheduler.exec in file "vendor/fiber/src/scheduler.ml",
-    line 76, characters 8-11
-  Re-raised at Stdune__Exn.raise_with_backtrace in file
-    "otherlibs/stdune/src/exn.ml", line 38, characters 27-56
-  Called from Fiber__Scheduler.exec in file "vendor/fiber/src/scheduler.ml",
-    line 76, characters 8-11
-  Re-raised at Stdune__Exn.raise_with_backtrace in file
-    "otherlibs/stdune/src/exn.ml", line 38, characters 27-56
-  Called from Fiber__Scheduler.exec in file "vendor/fiber/src/scheduler.ml",
-    line 76, characters 8-11
-  Re-raised at Stdune__Exn.raise_with_backtrace in file
-    "otherlibs/stdune/src/exn.ml", line 38, characters 27-56
-  Called from Fiber__Scheduler.exec in file "vendor/fiber/src/scheduler.ml",
-    line 76, characters 8-11
-  -> required by ("<unnamed>", ())
-  -> required by ("load-dir", In_build_dir "alt-context")
-  -> required by
-     ("build-alias", { dir = In_build_dir "alt-context"; name = "default" })
-  -> required by ("toplevel", ())
-
-  I must not crash.  Uncertainty is the mind-killer. Exceptions are the
-  little-death that brings total obliteration.  I will fully express my cases. 
-  Execution will pass over me and through me.  And when it has gone past, I
-  will unwind the stack along its path.  Where the cases are handled there will
-  be nothing.  Only I will remain.
-  [1]
 
 Let's add an exe to consume the library to trigger the error
 
@@ -122,27 +90,6 @@ Let's add an exe to consume the library to trigger the error
   > EOF
 
   $ dune build
-  Internal error, please report upstream including the contents of _build/log.
-  Description:
-    ("Lib.DB.get_compile_info got library that doesn't exist",
-    { name = "foo" })
-  Raised at Stdune__Code_error.raise in file
-    "otherlibs/stdune/src/code_error.ml", line 10, characters 30-62
-  Called from Fiber__Core.O.(>>|).(fun) in file "vendor/fiber/src/core.ml",
-    line 253, characters 36-41
-  Called from Fiber__Core.apply2 in file "vendor/fiber/src/core.ml", line 92,
-    characters 6-11
-  -> required by ("<unnamed>", ())
-  -> required by ("load-dir", In_build_dir "alt-context")
-  -> required by
-     ("build-alias", { dir = In_build_dir "alt-context"; name = "default" })
-  -> required by ("toplevel", ())
-
-  I must not crash.  Uncertainty is the mind-killer. Exceptions are the
-  little-death that brings total obliteration.  I will fully express my cases. 
-  Execution will pass over me and through me.  And when it has gone past, I
-  will unwind the stack along its path.  Where the cases are handled there will
-  be nothing.  Only I will remain.
   File "dune", line 3, characters 0-21:
   3 | (library
   4 |  (name foo))