Directly warn user when mixfile is not found (#297)

* Directly warn user when mixfile is not found

Without all three types of warnings it can be easy to miss this error,
especially if the file that you have open is not mix.exs

* Update changelog

Author: axelson

CHANGELOG.md

@@ -7,6 +7,7 @@ Improvements:
 - Support WorkspaceSymbols (go to symbol in workspace) without dialyzer being enabled (thanks [Jason Axelson](https://github.com/axelson)) [#263](https://github.com/elixir-lsp/elixir-ls/pull/263)
 - Display the version of Elixir used to compile ELixirLS (thanks [Jason Axelson](https://github.com/axelson)) [#264](https://github.com/elixir-lsp/elixir-ls/pull/264)
 - Support completion of callback function definitions (thanks [Marlus Saraiva](https://github.com/msaraiva)) [#265](https://github.com/elixir-lsp/elixir-ls/pull/265)
+- Give more direct warnings when mix.exs cannot be found (thanks [Jason Axelson](https://github.com/axelson)) [#297](https://github.com/elixir-lsp/elixir-ls/pull/297)
 
 Changes:
 - Major improvement/change: Improve autocomplete and signature help (thanks [Marlus Saraiva](https://github.com/msaraiva)) [#273](https://github.com/elixir-lsp/elixir-ls/pull/273)

apps/language_server/lib/language_server/build.ex

@@ -162,6 +162,9 @@ defmodule ElixirLS.LanguageServer.Build do
         "No mixfile found in project. " <>
           "To use a subdirectory, set `elixirLS.projectDir` in your settings"
 
+      JsonRpc.log_message(:error, msg <> ". Looked for mixfile at #{inspect(mixfile)}")
+      JsonRpc.show_message(:error, msg)
+
       {:error, [mixfile_diagnostic({Path.absname(mixfile), nil, msg}, :error)]}
     end
   end

apps/language_server/test/server_test.exs

@@ -317,7 +317,7 @@ defmodule ElixirLS.LanguageServer.ServerTest do
     end)
   end
 
-  test "reports error if no mixfile", %{server: server} do
+  test "reports errors if no mixfile", %{server: server} do
     in_fixture(__DIR__, "no_mixfile", fn ->
       mixfile_uri = SourceFile.path_to_uri("mix.exs")
 
@@ -333,6 +333,14 @@ defmodule ElixirLS.LanguageServer.ServerTest do
                        ]
                      }),
                      5000
+
+      assert_receive notification("window/logMessage", %{
+                       "message" => "No mixfile found in project." <> _
+                     })
+
+      assert_receive notification("window/showMessage", %{
+                       "message" => "No mixfile found in project." <> _
+                     })
     end)
   end