Introduce a compilation tracer

apps/language_server/lib/language_server.ex

@@ -9,7 +9,8 @@ defmodule ElixirLS.LanguageServer do
     children = [
       {ElixirLS.LanguageServer.Server, ElixirLS.LanguageServer.Server},
       {ElixirLS.LanguageServer.JsonRpc, name: ElixirLS.LanguageServer.JsonRpc},
-      {ElixirLS.LanguageServer.Providers.WorkspaceSymbols, []}
+      {ElixirLS.LanguageServer.Providers.WorkspaceSymbols, []},
+      {ElixirLS.LanguageServer.Tracer, []}
     ]
 
     opts = [strategy: :one_for_one, name: ElixirLS.LanguageServer.Supervisor, max_restarts: 0]

apps/language_server/lib/language_server/build.ex

@@ -1,5 +1,5 @@
 defmodule ElixirLS.LanguageServer.Build do
-  alias ElixirLS.LanguageServer.{Server, JsonRpc, Diagnostics}
+  alias ElixirLS.LanguageServer.{Server, JsonRpc, Diagnostics, Tracer}
   alias ElixirLS.Utils.MixfileHelpers
 
   def build(parent, root_path, opts) when is_binary(root_path) do
@@ -40,6 +40,7 @@ defmodule ElixirLS.LanguageServer.Build do
               end
             end)
 
+          Tracer.save()
           JsonRpc.log_message(:info, "Compile took #{div(us, 1000)} milliseconds")
         end)
       end)
@@ -213,4 +214,22 @@ defmodule ElixirLS.LanguageServer.Build do
 
     :ok
   end
+
+  def set_compiler_options(options \\ [], parser_options \\ []) do
+    parser_options =
+      parser_options
+      |> Keyword.merge(
+        columns: true,
+        token_metadata: true
+      )
+
+    options =
+      options
+      |> Keyword.merge(
+        tracers: [Tracer],
+        parser_options: parser_options
+      )
+
+    Code.compiler_options(options)
+  end
 end

apps/language_server/lib/language_server/cli.ex

@@ -1,11 +1,14 @@
 defmodule ElixirLS.LanguageServer.CLI do
   alias ElixirLS.Utils.{WireProtocol, Launch}
   alias ElixirLS.LanguageServer.JsonRpc
+  alias ElixirLS.LanguageServer.Build
 
   def main do
     WireProtocol.intercept_output(&JsonRpc.print/1, &JsonRpc.print_err/1)
     Launch.start_mix()
 
+    Build.set_compiler_options()
+
     start_language_server()
 
     IO.puts("Started ElixirLS v#{Launch.language_server_version()}")

apps/language_server/lib/language_server/providers/references.ex

@@ -17,7 +17,9 @@ defmodule ElixirLS.LanguageServer.Providers.References do
     {line, character} = SourceFile.lsp_position_to_elixir(text, {line, character})
 
     Build.with_build_lock(fn ->
-      ElixirSense.references(text, line, character)
+      trace = ElixirLS.LanguageServer.Tracer.get_trace()
+
+      ElixirSense.references(text, line, character, trace)
       |> Enum.map(fn elixir_sense_reference ->
         elixir_sense_reference
         |> build_reference(uri, text)

apps/language_server/lib/language_server/server.ex

@@ -35,6 +35,7 @@ defmodule ElixirLS.LanguageServer.Server do
   }
 
   alias ElixirLS.Utils.Launch
+  alias ElixirLS.LanguageServer.Tracer
 
   use Protocol
 
@@ -57,6 +58,7 @@ defmodule ElixirLS.LanguageServer.Server do
     source_files: %{},
     awaiting_contracts: [],
     supports_dynamic: false,
+    mix_project?: false,
     no_mixfile_warned?: false
   ]
 
@@ -415,6 +417,17 @@ defmodule ElixirLS.LanguageServer.Server do
              state.source_files[uri].dirty?)
       end)
 
+    # TODO remove uniq when duplicated subscriptions from vscode plugin are fixed
+    deleted_paths =
+      for change <- changes,
+          change["type"] == 3,
+          uniq: true,
+          do: SourceFile.path_from_uri(change["uri"])
+
+    for path <- deleted_paths do
+      Tracer.notify_file_deleted(path)
+    end
+
     source_files =
       changes
       |> Enum.reduce(state.source_files, fn
@@ -447,6 +460,7 @@ defmodule ElixirLS.LanguageServer.Server do
 
     state = %{state | source_files: source_files}
 
+    # TODO remove uniq when duplicated subscriptions from vscode plugin are fixed
     changes
     |> Enum.map(& &1["uri"])
     |> Enum.uniq()
@@ -1043,7 +1057,10 @@ defmodule ElixirLS.LanguageServer.Server do
         text
 
       {:error, reason} ->
-        IO.warn("Couldn't read file #{file}: #{inspect(reason)}")
+        if reason != :enoent do
+          IO.warn("Couldn't read file #{file}: #{inspect(reason)}")
+        end
+
         nil
     end
   end
@@ -1099,6 +1116,7 @@ defmodule ElixirLS.LanguageServer.Server do
       |> add_watched_extensions(additional_watched_extensions)
 
     state = create_gitignore(state)
+    Tracer.set_project_dir(state.project_dir)
     trigger_build(%{state | settings: settings})
   end
 
@@ -1211,7 +1229,7 @@ defmodule ElixirLS.LanguageServer.Server do
 
       is_nil(prev_project_dir) ->
         File.cd!(project_dir)
-        %{state | project_dir: File.cwd!()}
+        %{state | project_dir: File.cwd!(), mix_project?: File.exists?("mix.exs")}
 
       prev_project_dir != project_dir ->
         JsonRpc.show_message(