Skip docs requests for remote node intellisense (#2447)

lib/livebook/intellisense/docs.ex

@@ -1,6 +1,12 @@
 defmodule Livebook.Intellisense.Docs do
   # This module is responsible for extracting and normalizing
   # information like documentation, signatures and specs.
+  #
+  # Note that we only extract the docs information when requested for
+  # for the current node. For remote nodes, making several requests
+  # for docs (which may be necessary if there are multiple modules)
+  # adds to the overall latency. Remote intellisense is primarily used
+  # with remote release nodes, which have docs stripped out anyway.
 
   @type member_info :: %{
           kind: member_kind(),
@@ -38,6 +44,8 @@ defmodule Livebook.Intellisense.Docs do
   Fetches documentation for the given module if available.
   """
   @spec get_module_documentation(module(), node()) :: documentation()
+  def get_module_documentation(_module, node) when node != node(), do: nil
+
   def get_module_documentation(module, node) do
     case :erpc.call(node, Code, :fetch_docs, [module]) do
       {:docs_v1, _, _, format, %{"en" => docstring}, _, _} ->
@@ -75,7 +83,11 @@ defmodule Livebook.Intellisense.Docs do
           node(),
           keyword()
         ) :: list(member_info())
-  def lookup_module_members(module, members, node, opts \\ []) do
+  def lookup_module_members(module, members, node, opts \\ [])
+
+  def lookup_module_members(_module, _members, node, _opts) when node != node(), do: []
+
+  def lookup_module_members(module, members, node, opts) do
     members = MapSet.new(members)
     kinds = opts[:kinds] || [:function, :macro, :type]
 

test/livebook/remote_intellisense_test.exs

@@ -74,7 +74,7 @@ defmodule Livebook.RemoteIntellisenseTest do
                label: "RemoteModule",
                kind: :module,
                detail: "module",
-               documentation: "RemoteModule module docs",
+               documentation: "No documentation available",
                insert_text: "RemoteModule"
              } in Intellisense.get_completion_items("RemoteModule", context, node)
     end
@@ -85,8 +85,8 @@ defmodule Livebook.RemoteIntellisenseTest do
       assert %{
                label: "hello/1",
                kind: :function,
-               detail: "RemoteModule.hello(message)",
+               detail: nil,
-               documentation: "Hello doc",
+               documentation: "No documentation available",
                insert_text: "hello(${})"
              } in Intellisense.get_completion_items("RemoteModule.hel", context, node)
     end
@@ -97,20 +97,20 @@ defmodule Livebook.RemoteIntellisenseTest do
 
       assert [
                %{
-                 label: "all_keys/1",
+                 label: "unsubscribe/1",
                  kind: :function,
-                 detail: ":mnesia.all_keys/1",
+                 detail: nil,
-                 documentation: _all_keys_doc,
+                 documentation: "No documentation available",
-                 insert_text: "all_keys(${})"
+                 insert_text: "unsubscribe(${})"
                }
-             ] = Intellisense.get_completion_items(":mnesia.all", context, node)
+             ] = Intellisense.get_completion_items(":mnesia.unsub", context, node)
     end
 
     test "get details", %{node: node} do
       context = eval(do: nil)
 
       assert %{contents: [content]} = Intellisense.get_details("RemoteModule", 6, context, node)
-      assert content =~ "RemoteModule module docs"
+      assert content =~ "No documentation available"
     end
   end
 end