Fix signature completion and signature types in older Erlang docs (#1318)

lib/livebook/intellisense.ex

@@ -625,8 +625,7 @@ defmodule Livebook.Intellisense do
   end
 
   defp build_md(iodata, [{:ul, [{:class, "types"} | _], content} | ast]) do
-    lines = Enum.map(content, fn {:li, _, line} -> line end)
-    render_code_block(lines, "erlang") |> append_block(iodata) |> build_md(ast)
+    render_types_list(content) |> append_block(iodata) |> build_md(ast)
   end
 
   defp build_md(iodata, [{:ul, _, content} | ast]) do
@@ -735,4 +734,23 @@ defmodule Livebook.Intellisense do
     end)
     |> render_unordered_list()
   end
+
+  defp render_types_list(content) do
+    content
+    |> group_type_list_items([])
+    |> render_unordered_list()
+  end
+
+  defp group_type_list_items([], acc), do: Enum.reverse(acc)
+
+  defp group_type_list_items([{:li, [{:class, "type"}], content} | items], acc) do
+    group_type_list_items(items, [{:li, [], [{:code, [], content}]} | acc])
+  end
+
+  defp group_type_list_items(
+         [{:li, [{:class, "description"}], content} | items],
+         [{:li, [], prev_content} | acc]
+       ) do
+    group_type_list_items(items, [{:li, [], prev_content ++ [{:p, [], content}]} | acc])
+  end
 end

lib/livebook/intellisense/signature_matcher.ex

@@ -68,6 +68,9 @@ defmodule Livebook.Intellisense.SignatureMatcher do
   end
 
   defp fix_erlang_signature(signature, specs) do
+    # Erlang signatures may include "->" followed by return type
+    signature = signature |> String.split("->") |> hd() |> String.trim()
+
     case parse_erlang_signature(signature) do
       {:ok, fun, arity} ->
         args =

test/livebook/intellisense_test.exs

@@ -1224,6 +1224,14 @@ defmodule Livebook.IntellisenseTest do
       assert file_read =~ "Typical error reasons:"
     end
 
+    @tag :erl_docs
+    test "properly renders Erlang signature types list" do
+      context = eval(do: nil)
+
+      assert %{contents: [file_read]} = Intellisense.get_details(":odbc.connect()", 8, context)
+      assert file_read =~ "Ref = connection_reference()"
+    end
+
     test "properly parses unicode" do
       context = eval(do: nil)
 
@@ -1429,6 +1437,22 @@ defmodule Livebook.IntellisenseTest do
              } = Intellisense.get_signature_items(":lists.map(", context)
     end
 
+    @tag :erl_docs
+    test "shows signature with arguments for erlang modules with arrow signature" do
+      context = eval(do: nil)
+
+      assert %{
+               active_argument: 0,
+               signature_items: [
+                 %{
+                   signature: "connect(ConnectStr, Options)",
+                   arguments: ["ConnectStr", "Options"],
+                   documentation: _connect_doc
+                 }
+               ]
+             } = Intellisense.get_signature_items(":odbc.connect(", context)
+    end
+
     test "returns call active argument" do
       context = eval(do: nil)