feat: use pkg-install to build the deps

Attached it to the workspace.

Signed-off-by: Etienne Marais <[email protected]>

src/dune_rules/alias0.ml

@@ -25,5 +25,5 @@ let check = standard "check"
 let install = standard "install"
 let ocaml_index = standard "ocaml-index"
 let runtest = standard "runtest"
-let pkg_deps = standard "pkg-deps"
+let pkg_install = standard "pkg-install"
 let all = standard "all"

src/dune_rules/alias0.mli

@@ -14,7 +14,7 @@ val check : Name.t
 val ocaml_index : Name.t
 val install : Name.t
 val runtest : Name.t
-val pkg_deps : Name.t
+val pkg_install : Name.t
 val all : Name.t
 val is_standard : Name.t -> bool
 val register_as_standard : Name.t -> unit

src/dune_rules/gen_rules.ml

@@ -355,6 +355,17 @@ let gen_project_rules =
     and+ () = Odoc.gen_project_rules sctx project
     and+ () = Odoc_new.gen_project_rules sctx project
     and+ () = Ocaml_index.project_rule sctx project
+    and+ () =
+      let ctx = Super_context.context sctx in
+      let ctx_name = Context.name ctx in
+      let* is_lock_dir_active = Lock_dir.lock_dir_active ctx_name in
+      if is_lock_dir_active
+      then (
+        let dir =
+          Path.Build.append_source (Context.build_dir ctx) @@ Dune_project.root project
+        in
+        Pkg_rules.gen_rule_from_universe ~dir ctx_name)
+      else Memo.return ()
     and+ () =
       let version = 2, 8 in
       match Dune_project.allow_approximate_merlin project with

src/dune_rules/pkg_rules.ml

@@ -1937,14 +1937,29 @@ let build_rule context_name ~source_deps (pkg : Pkg.t) =
        ~directory_targets:[ pkg.write_paths.target_dir ]
 ;;
 
-let gen_package_alias_rules ~dir source_deps =
-  let alias = Alias.make Alias0.pkg_deps ~dir in
-  Action_builder.deps source_deps |> Rules.Produce.Alias.add_deps alias
+let gen_rule_from_universe ~dir ctx_name =
+  let to_target_path pkg =
+    let pkg_name = Dune_lang.Package_name.to_string pkg in
+    let path =
+      Path.Build.L.relative
+        Private_context.t.build_dir
+        [ Context_name.to_string ctx_name; ".pkg"; pkg_name; "target" ]
+      |> Path.build
+    in
+    path
+  in
+  let* packages =
+    Package_universe.lock_dir (Project_dependencies ctx_name)
+    >>| (fun lock_dir -> lock_dir.packages)
+    >>| Dune_lang.Package_name.Map.keys
+  in
+  let alias = Alias.make Alias0.pkg_install ~dir in
+  let package_targets = List.map ~f:to_target_path packages in
+  Action_builder.paths package_targets |> Rules.Produce.Alias.add_deps alias
 ;;
 
-let gen_rules ~dir context_name (pkg : Pkg.t) =
+let gen_rules context_name (pkg : Pkg.t) =
   let* source_deps, copy_rules = source_rules pkg in
-  let* () = gen_package_alias_rules ~dir source_deps in
   let* () = copy_rules
   and* build_rule = build_rule context_name pkg ~source_deps in
   rule ~loc:Loc.none (* TODO *) build_rule
@@ -1986,7 +2001,7 @@ let setup_package_rules ~package_universe ~dir ~pkg_name : Gen_rules.result Memo
     Gen_rules.Build_only_sub_dirs.singleton ~dir Subdir_set.empty
   in
   let context_name = Package_universe.context_name package_universe in
-  let rules = Rules.collect_unit (fun () -> gen_rules ~dir context_name pkg) in
+  let rules = Rules.collect_unit (fun () -> gen_rules context_name pkg) in
   Gen_rules.make ~directory_targets ~build_dir_only_sub_dirs rules
 ;;
 

src/dune_rules/pkg_rules.mli

@@ -22,3 +22,6 @@ val which : Context_name.t -> (Filename.t -> Path.t option Memo.t) Staged.t
 val exported_env : Context_name.t -> Env.t Memo.t
 val ocamlpath : Context_name.t -> Path.t list Memo.t
 val find_package : Context_name.t -> Package.Name.t -> unit Action_builder.t option Memo.t
+
+(** TODO: Give me a better description. *)
+val gen_rule_from_universe : dir:Path.Build.t -> Context_name.t -> unit Memo.t