Basic single file/dir with no mixfile support

apps/language_server/lib/language_server/build.ex

@@ -1,7 +1,7 @@
 defmodule ElixirLS.LanguageServer.Build do
   alias ElixirLS.LanguageServer.{Server, JsonRpc, SourceFile, Diagnostics}
 
-  def build(parent, root_path, opts) do
+  def build(parent, root_path, opts) when is_binary(root_path) 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}
@@ -37,6 +37,9 @@ defmodule ElixirLS.LanguageServer.Build do
 
                 {:error, mixfile_diagnostics} ->
                   Server.build_finished(parent, {:error, mixfile_diagnostics})
+
+                :no_mixfile ->
+                  Server.build_finished(parent, {:no_mixfile, []})
               end
             end)
 
@@ -165,10 +168,9 @@ 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)
+      JsonRpc.log_message(:info, msg <> ". Looked for mixfile at #{inspect(mixfile)}")
 
-      {:error, [mixfile_diagnostic({Path.absname(mixfile), nil, msg}, :error)]}
+      :no_mixfile
     end
   end
 

apps/language_server/lib/language_server/providers/formatting.ex

@@ -2,19 +2,12 @@ defmodule ElixirLS.LanguageServer.Providers.Formatting do
   import ElixirLS.LanguageServer.Protocol, only: [range: 4]
   alias ElixirLS.LanguageServer.SourceFile
 
-  def format(%SourceFile{} = source_file, uri, project_dir) do
+  def format(%SourceFile{} = source_file, uri, project_dir) when is_binary(project_dir) do
     if can_format?(uri, project_dir) do
       case SourceFile.formatter_opts(uri) do
         {:ok, opts} ->
           if should_format?(uri, project_dir, opts[:inputs]) do
-            formatted = IO.iodata_to_binary([Code.format_string!(source_file.text, opts), ?\n])
-
-            response =
-              source_file.text
-              |> String.myers_difference(formatted)
-              |> myers_diff_to_text_edits()
-
-            {:ok, response}
+            do_format(source_file, opts)
           else
             {:ok, []}
           end
@@ -29,6 +22,21 @@ defmodule ElixirLS.LanguageServer.Providers.Formatting do
 
       {:error, :internal_error, msg}
     end
+  end
+
+  def format(%SourceFile{} = source_file, _uri, nil) do
+    do_format(source_file)
+  end
+
+  defp do_format(%SourceFile{text: text}, opts \\ []) do
+    formatted = IO.iodata_to_binary([Code.format_string!(text, opts), ?\n])
+
+    response =
+      text
+      |> String.myers_difference(formatted)
+      |> myers_diff_to_text_edits()
+
+    {:ok, response}
   rescue
     _e in [TokenMissingError, SyntaxError] ->
       {:error, :internal_error, "Unable to format due to syntax error"}