render metadata in signature help

Fixes #1064

Author: lukaszsamson

apps/language_server/lib/language_server/providers/signature_help.ex

@@ -4,6 +4,7 @@ defmodule ElixirLS.LanguageServer.Providers.SignatureHelp do
   """
   alias ElixirLS.LanguageServer.{SourceFile, Parser}
   alias ElixirLS.LanguageServer.Providers.SignatureHelp.Signature
+  alias ElixirLS.LanguageServer.MarkdownUtils
 
   def trigger_characters(), do: ["(", ","]
 
@@ -29,7 +30,13 @@ defmodule ElixirLS.LanguageServer.Providers.SignatureHelp do
   end
 
   defp signature_response(
-         %{documentation: documentation, name: name, params: params, spec: spec} = signature
+         %{
+           documentation: documentation,
+           name: name,
+           params: params,
+           spec: spec,
+           metadata: metadata
+         } = signature
        ) do
     params_info = for param <- params, do: %{"label" => param}
 
@@ -47,18 +54,36 @@ defmodule ElixirLS.LanguageServer.Providers.SignatureHelp do
 
     case {spec, documentation} do
       {"", ""} ->
-        response
+        put_metadata(response, metadata)
 
       {"", _} ->
         put_documentation(response, documentation)
+        |> put_metadata(metadata)
 
       {_, _} ->
         spec_str = SourceFile.format_spec(spec, line_length: 42)
+
         put_documentation(response, "#{documentation}\n#{spec_str}")
+        |> put_metadata(metadata)
     end
   end
 
   defp put_documentation(response, documentation) do
     Map.put(response, "documentation", %{"kind" => "markdown", "value" => documentation})
   end
+
+  defp put_metadata(response, metadata) do
+    if metadata do
+      metadata_md = MarkdownUtils.get_metadata_md(metadata)
+
+      if metadata_md != "" do
+        current_docs = get_in(response, ["documentation", "value"]) || ""
+        put_documentation(response, metadata_md <> "\n\n" <> current_docs)
+      else
+        response
+      end
+    else
+      response
+    end
+  end
 end

apps/language_server/lib/language_server/providers/signature_help/signature.ex

@@ -121,20 +121,27 @@ defmodule ElixirLS.LanguageServer.Providers.SignatureHelp.Signature do
                       |> Enum.reject(&String.starts_with?(&1, "@spec"))
                       |> Enum.reverse()
 
-                    callback_doc =
+                    {callback_doc, callback_meta} =
                       case metadata.mods_funs_to_positions[{behaviour, fun, arity}] do
                         nil ->
-                          spec_info.doc
+                          {spec_info.doc, spec_info.meta}
 
                         def_info ->
                           # in case of protocol implementation get doc and meta from def
-                          def_info.doc
+                          {def_info.doc, def_info.meta}
                       end
 
+                    # Merge metadata from both the implementation and the behaviour
+                    metadata =
+                      callback_meta
+                      |> Map.merge(signature.metadata)
+                      |> Map.put(:implementing, behaviour)
+
                     %{
                       signature
                       | spec: specs |> Enum.join("\n"),
-                        documentation: Introspection.extract_summary_from_docs(callback_doc)
+                        documentation: Introspection.extract_summary_from_docs(callback_doc),
+                        metadata: metadata
                     }
 
                   nil ->
@@ -151,7 +158,7 @@ defmodule ElixirLS.LanguageServer.Providers.SignatureHelp.Signature do
                           State.ModFunInfo.get_category(fun_info)
                       end
 
-                    {spec, doc, _} =
+                    {spec, doc, callback_meta} =
                       Metadata.get_doc_spec_from_behaviour(
                         behaviour,
                         fun,
@@ -162,7 +169,8 @@ defmodule ElixirLS.LanguageServer.Providers.SignatureHelp.Signature do
                     %{
                       signature
                       | documentation: Introspection.extract_summary_from_docs(doc),
-                        spec: spec
+                        spec: spec,
+                        metadata: callback_meta |> Map.merge(signature.metadata)
                     }
                 end
             end

apps/language_server/test/providers/references/locator_test.exs

@@ -2330,7 +2330,7 @@ defmodule ElixirLS.LanguageServer.Providers.References.LocatorTest do
 
       metadata = ElixirSense.Core.Parser.parse_file(file, false, false, {1, 1})
 
-      groupped_calls =
+      grouped_calls =
         metadata.calls
         |> Enum.flat_map(fn {_, list} ->
           list
@@ -2347,7 +2347,7 @@ defmodule ElixirLS.LanguageServer.Providers.References.LocatorTest do
         end)
         |> Enum.group_by(fn item -> item.callee end)
 
-      assert groupped_calls == filtered_trace
+      assert grouped_calls == filtered_trace
     end
   end