Add mix clean custom command

apps/language_server/lib/language_server/build.ex

@@ -27,7 +27,7 @@ defmodule ElixirLS.LanguageServer.Build do
 
                   # if we won't do it elixir >= 1.11 warns that protocols have already been consolidated
                   purge_consolidated_protocols()
-                  {status, diagnostics} = compile()
+                  {status, diagnostics} = run_mix_compile()
 
                   diagnostics = Diagnostics.normalize(diagnostics, root_path)
                   Server.build_finished(parent, {status, mixfile_diagnostics ++ diagnostics})
@@ -46,6 +46,13 @@ defmodule ElixirLS.LanguageServer.Build do
     end
   end
 
+  def clean(clean_deps? \\ false) do
+    with_build_lock(fn ->
+      Mix.Task.clear()
+      run_mix_clean(clean_deps?)
+    end)
+  end
+
   def with_build_lock(func) do
     :global.trans({__MODULE__, self()}, func)
   end
@@ -104,7 +111,8 @@ defmodule ElixirLS.LanguageServer.Build do
     end
   end
 
-  defp compile do
+  defp run_mix_compile do
+    # TODO consider adding --no-compile
     case Mix.Task.run("compile", ["--return-errors", "--ignore-module-conflict"]) do
       {status, diagnostics} when status in [:ok, :error, :noop] and is_list(diagnostics) ->
         {status, diagnostics}
@@ -117,6 +125,26 @@ defmodule ElixirLS.LanguageServer.Build do
     end
   end
 
+  defp run_mix_clean(clean_deps?) do
+    opts = []
+
+    opts =
+      if clean_deps? do
+        opts ++ ["--deps"]
+      else
+        opts
+      end
+
+    results = Mix.Task.run("clean", opts) |> List.wrap()
+
+    if Enum.all?(results, &match?(:ok, &1)) do
+      :ok
+    else
+      JsonRpc.log_message(:error, "mix clean returned #{inspect(results)}")
+      {:error, :clean_failed}
+    end
+  end
+
   defp purge_consolidated_protocols do
     config = Mix.Project.config()
     path = Mix.Project.consolidation_path(config)

apps/language_server/lib/language_server/providers/execute_command.ex

@@ -9,7 +9,8 @@ defmodule ElixirLS.LanguageServer.Providers.ExecuteCommand do
     "spec" => ExecuteCommand.ApplySpec,
     "expandMacro" => ExecuteCommand.ExpandMacro,
     "manipulatePipes" => ExecuteCommand.ManipulatePipes,
-    "restart" => ExecuteCommand.Restart
+    "restart" => ExecuteCommand.Restart,
+    "mixClean" => ExecuteCommand.MixClean
   }
 
   @callback execute([any], %ElixirLS.LanguageServer.Server{}) ::

apps/language_server/lib/language_server/providers/execute_command/mix_clean.ex

@@ -0,0 +1,11 @@
+defmodule ElixirLS.LanguageServer.Providers.ExecuteCommand.MixClean do
+  @behaviour ElixirLS.LanguageServer.Providers.ExecuteCommand
+
+  @impl ElixirLS.LanguageServer.Providers.ExecuteCommand
+  def execute([clean_deps?], _state) do
+    case ElixirLS.LanguageServer.Build.clean(clean_deps?) do
+      :ok -> {:ok, %{}}
+      {:error, reason} -> {:error, :server_error, inspect(reason)}
+    end
+  end
+end

apps/language_server/test/fixtures/clean/lib/a.ex

@@ -0,0 +1,5 @@
+defmodule A do
+  def fun do
+    :ok = B.fun()
+  end
+end

apps/language_server/test/fixtures/clean/lib/b.ex

@@ -0,0 +1,5 @@
+defmodule B do
+  def fun do
+    :error
+  end
+end

apps/language_server/test/fixtures/clean/lib/c.ex

@@ -0,0 +1,5 @@
+defmodule C do
+  def myfun do
+    1
+  end
+end

apps/language_server/test/fixtures/clean/mix.exs

@@ -0,0 +1,15 @@
+defmodule ElixirLS.LanguageServer.Fixtures.Clean.Mixfile do
+  use Mix.Project
+
+  def project do
+    [app: :els_clean_test, version: "0.1.0"]
+  end
+
+  # Configuration for the OTP application
+  #
+  # Type "mix help compile.app" for more information
+  def application do
+    # Specify extra applications you'll use from Erlang/Elixir
+    []
+  end
+end

apps/language_server/test/providers/execute_command/mix_clean_test.exs

@@ -0,0 +1,47 @@
+defmodule ElixirLS.LanguageServer.Providers.ExecuteCommand.MixCleanTest do
+  alias ElixirLS.LanguageServer.{Server, Protocol, SourceFile}
+  use ElixirLS.Utils.MixTest.Case, async: false
+  use Protocol
+
+  setup do
+    server = ElixirLS.LanguageServer.Test.ServerTestHelpers.start_server()
+
+    {:ok, %{server: server}}
+  end
+
+  @tag fixture: true
+  test "mix clean", %{server: server} do
+    in_fixture(Path.join(__DIR__, "../.."), "clean", fn ->
+      root_uri = SourceFile.path_to_uri(File.cwd!())
+      Server.receive_packet(server, initialize_req(1, root_uri, %{}))
+
+      Server.receive_packet(
+        server,
+        did_change_configuration(%{
+          "elixirLS" => %{"dialyzerEnabled" => false}
+        })
+      )
+
+      assert_receive %{
+                       "method" => "window/logMessage",
+                       "params" => %{"message" => "Compile took" <> _}
+                     },
+                     20000
+
+      path = ".elixir_ls/build/test/lib/els_clean_test/ebin/Elixir.A.beam"
+      assert File.exists?(path)
+
+      server_instance_id = :sys.get_state(server).server_instance_id
+
+      Server.receive_packet(
+        server,
+        execute_command_req(4, "mixClean:#{server_instance_id}", [false])
+      )
+
+      res = assert_receive(%{"id" => 4}, 5000)
+      assert res["result"] == %{}
+
+      refute File.exists?(path)
+    end)
+  end
+end