Emit parser warnings and errors on type (#986)

* remove not needed monitor

* emit diagnostics from parser on edit

* react to closing and opening

* only parse ex and exs

* handle eex files

* use with_diagnostics

* use common error handling

handle unexpected errors

* fix tests

* add tests

* fix paths on windows

* don't assert on error message

* eex extension

* don't assert warnings on elixir < 1.15.3

* remove addressed todos

Author: lukaszsamson

apps/language_server/lib/language_server/server.ex

@@ -49,6 +49,8 @@ defmodule ElixirLS.LanguageServer.Server do
     :root_uri,
     :project_dir,
     :settings,
+    parse_file_refs: %{},
+    parser_diagnostics: %{},
     build_diagnostics: [],
     dialyzer_diagnostics: [],
     needs_build?: false,
@@ -270,6 +272,47 @@ defmodule ElixirLS.LanguageServer.Server do
     {:noreply, state}
   end
 
+  @impl GenServer
+  def handle_info(
+        {:parse_file, uri},
+        %__MODULE__{source_files: source_files} = state
+      ) do
+    old_diagnostics =
+      state.build_diagnostics ++
+        state.dialyzer_diagnostics ++ List.flatten(Map.values(state.parser_diagnostics))
+
+    parser_diagnostics =
+      case source_files[uri] do
+        %SourceFile{} = source_file ->
+          file = SourceFile.Path.from_uri(uri)
+          case parse_file(source_file.text, file) do
+            [] ->
+              Map.delete(state.parser_diagnostics, uri)
+
+            diagnostics ->
+              Map.put(state.parser_diagnostics, uri, diagnostics)
+          end
+
+        nil ->
+          Map.delete(state.parser_diagnostics, uri)
+      end
+
+    state = %{
+      state
+      | parser_diagnostics: parser_diagnostics,
+        parse_file_refs: Map.delete(state.parse_file_refs, uri)
+    }
+
+    publish_diagnostics(
+      state.build_diagnostics ++
+        state.dialyzer_diagnostics ++ List.flatten(Map.values(state.parser_diagnostics)),
+      old_diagnostics,
+      state.source_files
+    )
+
+    {:noreply, state}
+  end
+
   ## Helpers
 
   defp handle_notification(notification("initialized"), state = %__MODULE__{}) do
@@ -381,13 +424,9 @@ defmodule ElixirLS.LanguageServer.Server do
     else
       source_file = %SourceFile{text: text, version: version}
 
-      Diagnostics.publish_file_diagnostics(
-        uri,
-        state.build_diagnostics ++ state.dialyzer_diagnostics,
-        source_file
-      )
-
-      put_in(state.source_files[uri], source_file)
+      state = put_in(state.source_files[uri], source_file)
+      # parse handler will emit diagnostics for opened file
+      trigger_parse(state, uri, 0)
     end
   end
 
@@ -402,6 +441,9 @@ defmodule ElixirLS.LanguageServer.Server do
     else
       awaiting_contracts = reject_awaiting_contracts(state.awaiting_contracts, uri)
 
+      # parse handler will clean up diagnostics and refs for closed file
+      state = trigger_parse(state, uri, 0)
+
       %{
         state
         | source_files: Map.delete(state.source_files, uri),
@@ -421,10 +463,14 @@ defmodule ElixirLS.LanguageServer.Server do
 
       state
     else
-      update_in(state.source_files[uri], fn source_file ->
-        %SourceFile{source_file | version: version, dirty?: true}
-        |> SourceFile.apply_content_changes(content_changes)
-      end)
+      state =
+        update_in(state.source_files[uri], fn source_file ->
+          %SourceFile{source_file | version: version, dirty?: true}
+          |> SourceFile.apply_content_changes(content_changes)
+        end)
+
+      # trigger parse with debounce
+      trigger_parse(state, uri, 300)
     end
   end
 
@@ -1039,7 +1085,10 @@ defmodule ElixirLS.LanguageServer.Server do
   end
 
   defp handle_build_result(status, diagnostics, state = %__MODULE__{}) do
-    old_diagnostics = state.build_diagnostics ++ state.dialyzer_diagnostics
+    old_diagnostics =
+      state.build_diagnostics ++
+        state.dialyzer_diagnostics ++ List.flatten(Map.values(state.parser_diagnostics))
+
     state = put_in(state.build_diagnostics, diagnostics)
 
     state =
@@ -1055,7 +1104,8 @@ defmodule ElixirLS.LanguageServer.Server do
       end
 
     publish_diagnostics(
-      state.build_diagnostics ++ state.dialyzer_diagnostics,
+      state.build_diagnostics ++
+        state.dialyzer_diagnostics ++ List.flatten(Map.values(state.parser_diagnostics)),
       old_diagnostics,
       state.source_files
     )
@@ -1432,4 +1482,82 @@ defmodule ElixirLS.LanguageServer.Server do
       state
     end
   end
+
+  defp trigger_parse(state, uri, debounce_timeout) do
+    if String.ends_with?(uri, [".ex", ".exs", ".eex"]) do
+      update_in(state.parse_file_refs[uri], fn old_ref ->
+        if old_ref do
+          Process.cancel_timer(old_ref, info: false)
+        end
+
+        Process.send_after(self(), {:parse_file, uri}, debounce_timeout)
+      end)
+    else
+      state
+    end
+  end
+
+  defp parse_file(text, file) do
+    {result, raw_diagnostics} =
+      Build.with_diagnostics([log: false], fn ->
+        try do
+          parser_options = [
+            file: file,
+            columns: true
+          ]
+
+          if String.ends_with?(file, ".eex") do
+            EEx.compile_string(text,
+              file: file,
+              parser_options: parser_options
+            )
+          else
+            Code.string_to_quoted!(text, parser_options)
+          end
+
+          :ok
+        rescue
+          e in [EEx.SyntaxError, SyntaxError, TokenMissingError] ->
+            message = Exception.message(e)
+
+            diagnostic = %Mix.Task.Compiler.Diagnostic{
+              compiler_name: "ElixirLS",
+              file: file,
+              position: {e.line, e.column},
+              message: message,
+              severity: :error
+            }
+
+            {:error, diagnostic}
+
+          e ->
+            message = Exception.message(e)
+
+            diagnostic = %Mix.Task.Compiler.Diagnostic{
+              compiler_name: "ElixirLS",
+              file: file,
+              position: {1, 1},
+              message: message,
+              severity: :error
+            }
+
+            # e.g. https://github.com/elixir-lang/elixir/issues/12926
+            Logger.warning(
+              "Unexpected parser error, please report it to elixir project https://github.com/elixir-lang/elixir/issues\n" <>
+                Exception.format(:error, e, __STACKTRACE__)
+            )
+
+            {:error, diagnostic}
+        end
+      end)
+
+    warning_diagnostics =
+      raw_diagnostics
+      |> Enum.map(&Diagnostics.code_diagnostic/1)
+
+    case result do
+      :ok -> warning_diagnostics
+      {:error, diagnostic} -> [diagnostic | warning_diagnostics]
+    end
+  end
 end

apps/language_server/mix.exs

@@ -31,7 +31,7 @@ defmodule ElixirLS.LanguageServer.Mixfile do
   end
 
   def application do
-    [mod: {ElixirLS.LanguageServer, []}, extra_applications: [:logger]]
+    [mod: {ElixirLS.LanguageServer, []}, extra_applications: [:logger, :eex]]
   end
 
   defp deps do

apps/language_server/test/dialyzer_test.exs

@@ -112,8 +112,6 @@ defmodule ElixirLS.LanguageServer.DialyzerTest do
   @tag slow: true, fixture: true
   test "only analyzes the changed files", %{server: server} do
     in_fixture(__DIR__, "dialyzer", fn ->
-      file_c = SourceFile.Path.to_uri(Path.absname("lib/c.ex"))
-
       capture_log(fn ->
         initialize(server, %{"dialyzerEnabled" => true, "dialyzerFormat" => "dialyxir_long"})
 
@@ -149,8 +147,6 @@ defmodule ElixirLS.LanguageServer.DialyzerTest do
                        }),
                        3_000
 
-        assert_receive publish_diagnostics_notif(^file_c, []), 20_000
-
         assert_receive notification("window/logMessage", %{
                          "message" => "[ElixirLS Dialyzer] Done writing manifest" <> _
                        }),
@@ -376,9 +372,6 @@ defmodule ElixirLS.LanguageServer.DialyzerTest do
 
       assert_receive notification("window/logMessage", %{"message" => "Compile took" <> _}), 5000
 
-      assert_receive notification("textDocument/publishDiagnostics", %{"diagnostics" => []}),
-                     30000
-
       Process.sleep(2000)
 
       v2_text = """