Load all modules after first build

apps/language_server/lib/language_server/build.ex

@@ -1,7 +1,7 @@
 defmodule ElixirLS.LanguageServer.Build do
   alias ElixirLS.LanguageServer.{Server, JsonRpc, SourceFile}
 
-  def build(parent, root_path, fetch_deps?) do
+  def build(parent, root_path, opts) do
     if Path.absname(File.cwd!()) != Path.absname(root_path) do
       IO.puts("Skipping build because cwd changed from #{root_path} to #{File.cwd!()}")
       {nil, nil}
@@ -19,10 +19,16 @@ defmodule ElixirLS.LanguageServer.Build do
               case reload_project() do
                 {:ok, mixfile_diagnostics} ->
                   # FIXME: Private API
-                  if fetch_deps? and Mix.Dep.load_on_environment([]) != prev_deps,
-                    do: fetch_deps()
+                  if Keyword.get(opts, :fetch_deps?) and
+                       Mix.Dep.load_on_environment([]) != prev_deps,
+                     do: fetch_deps()
 
                   {status, diagnostics} = compile()
+
+                  if status in [:ok, :noop] and Keyword.get(opts, :load_all_modules?) do
+                    load_all_modules()
+                  end
+
                   Server.build_finished(parent, {status, mixfile_diagnostics ++ diagnostics})
 
                 {:error, mixfile_diagnostics} ->
@@ -160,6 +166,29 @@ defmodule ElixirLS.LanguageServer.Build do
     end
   end
 
+  defp load_all_modules do
+    apps =
+      cond do
+        Mix.Project.umbrella?() ->
+          Mix.Project.apps_paths() |> Map.keys()
+
+        app = Keyword.get(Mix.Project.config(), :app) ->
+          [app]
+
+        true ->
+          []
+      end
+
+    Enum.each(apps, fn app ->
+      true = Code.prepend_path(Path.join(Mix.Project.build_path(), "lib/#{app}/ebin"))
+
+      case Application.load(app) do
+        :ok -> :ok
+        {:error, {:already_loaded, _}} -> :ok
+      end
+    end)
+  end
+
   defp compile do
     case Mix.Task.run("compile", ["--return-errors", "--ignore-module-conflict"]) do
       {status, diagnostics} when status in [:ok, :error, :noop] and is_list(diagnostics) ->

apps/language_server/lib/language_server/protocol.ex

@@ -191,6 +191,18 @@ defmodule ElixirLS.LanguageServer.Protocol do
     end
   end
 
+  defmacro shutdown_req(id) do
+    quote do
+      request(unquote(id), "shutdown", %{})
+    end
+  end
+
+  defmacro exit_req(id) do
+    quote do
+      request(unquote(id), "exit", %{})
+    end
+  end
+
   # Other utilities
 
   defmacro range(start_line, start_character, end_line, end_character) do

apps/language_server/lib/language_server/server.ex

@@ -44,6 +44,7 @@ defmodule ElixirLS.LanguageServer.Server do
     build_diagnostics: [],
     dialyzer_diagnostics: [],
     needs_build?: false,
+    load_all_modules?: false,
     build_running?: false,
     analysis_ready?: false,
     received_shutdown?: false,
@@ -567,14 +568,20 @@ defmodule ElixirLS.LanguageServer.Server do
   defp trigger_build(state) do
     if build_enabled?(state) and not state.build_running? do
       fetch_deps? = Map.get(state.settings || %{}, "fetchDeps", true)
-      {_pid, build_ref} = Build.build(self(), state.project_dir, fetch_deps?)
+
+      {_pid, build_ref} =
+        Build.build(self(), state.project_dir,
+          fetch_deps?: fetch_deps?,
+          load_all_modules?: state.load_all_modules?
+        )
 
       %__MODULE__{
         state
         | build_ref: build_ref,
           needs_build?: false,
           build_running?: true,
-          analysis_ready?: false
+          analysis_ready?: false,
+          load_all_modules?: false
       }
     else
       %__MODULE__{state | needs_build?: true, analysis_ready?: false}
@@ -771,7 +778,7 @@ defmodule ElixirLS.LanguageServer.Server do
 
       is_nil(prev_project_dir) ->
         File.cd!(project_dir)
-        put_in(state.project_dir, project_dir)
+        Map.merge(state, %{project_dir: project_dir, load_all_modules?: true})
 
       prev_project_dir != project_dir ->
         JsonRpc.show_message(

apps/language_server/test/fixtures/umbrella/apps/app2/lib/app2/foo.ex

@@ -0,0 +1,5 @@
+defmodule App2.Foo do
+  def hello do
+    :foo
+  end
+end

apps/language_server/test/server_test.exs

@@ -336,4 +336,56 @@ defmodule ElixirLS.LanguageServer.ServerTest do
              ]) = resp
     end)
   end
+
+  test "loading of umbrella app dependencies", %{server: server} do
+    in_fixture(__DIR__, "umbrella", fn ->
+      # We test this by opening the umbrella project twice.
+      # First to compile the applications and build the cache.
+      # Second time to see if loads modules
+      initialize(server)
+
+      # Upon first vist, server complies and loads all umbrella applications and modules
+      Process.sleep(1_500)
+
+      Server.receive_packet(server, shutdown_req(2))
+      assert response(2, nil) = assert_receive(%{"id" => 2}, 5000)
+      Server.receive_packet(server, exit_req(3))
+
+      Process.sleep(500)
+      # unload App2.Foo
+      purge([App2.Foo])
+
+      # Upon re-visiting, server does not attempt to compile umbrella applications
+      initialize(server)
+      Process.sleep(1_500)
+
+      file_path = "apps/app1/lib/bar.ex"
+      uri = SourceFile.path_to_uri(file_path)
+
+      code = """
+      defmodule Bar do
+        def fnuc, do: App2.Fo
+        #____________________^
+      end
+      """
+
+      Server.receive_packet(server, did_open(uri, "elixir", 1, code))
+      Server.receive_packet(server, completion_req(2, uri, 1, 23))
+
+      resp = assert_receive(%{"id" => 2}, 5000)
+
+      assert response(2, %{
+               "isIncomplete" => false,
+               "items" => [
+                 %{
+                   "detail" => "module",
+                   "documentation" => _,
+                   "kind" => 9,
+                   "label" => "Foo"
+                 }
+                 | _
+               ]
+             }) = resp
+    end)
+  end
 end