Do not reveal opaque type details in signature provider

Fixes #256

lib/elixir_sense/core/metadata.ex

@@ -327,24 +327,28 @@ defmodule ElixirSense.Core.Metadata do
   @spec get_type_signatures(__MODULE__.t(), module, atom) :: [signature_t]
   def get_type_signatures(%__MODULE__{} = metadata, module, type)
       when not is_nil(module) and not is_nil(type) do
-    case Map.get(metadata.types, {module, type, nil}) do
-      nil ->
-        []
-
-      %State.TypeInfo{args: args_variants} ->
-        for args <- args_variants do
-          arity = length(args)
-
-          spec = metadata.types[{module, type, arity}].specs |> Enum.join("\n")
-
-          %{
-            name: Atom.to_string(type),
-            params: args,
-            documentation: "",
-            spec: spec
-          }
+    metadata.types
+    |> Enum.filter(fn
+      {{^module, ^type, arity}, _type_info} when not is_nil(arity) -> true
+      _ -> false
+    end)
+    |> Enum.map(fn {_, %State.TypeInfo{} = type_info} ->
+      args = type_info.args |> List.last() |> Enum.join(", ")
+
+      spec =
+        case type_info.kind do
+          :opaque -> "@opaque #{type}(#{args})"
+          _ -> List.last(type_info.specs)
         end
-    end
+
+      %{
+        name: Atom.to_string(type),
+        params: type_info.args |> List.last(),
+        # TODO extract docs
+        documentation: "",
+        spec: spec
+      }
+    end)
   end
 
   def get_docs_specs_from_behaviours(env) do

lib/elixir_sense/core/type_info.ex

@@ -67,7 +67,8 @@ defmodule ElixirSense.Core.TypeInfo do
           type_args = Enum.map(args, &(&1 |> elem(2) |> Atom.to_string()))
           type_str = Atom.to_string(type)
           doc = Introspection.extract_summary_from_docs(text)
-          spec = get_type_spec_as_string(mod, type, arity)
+          typedef = get_type_spec(mod, type, arity)
+          spec = format_type_spec(typedef, line_length: @param_option_spec_line_length)
           %{name: type_str, params: type_args, documentation: doc, spec: spec}
         end
 
@@ -81,7 +82,7 @@ defmodule ElixirSense.Core.TypeInfo do
             name: Atom.to_string(name),
             params: type_args,
             documentation: "",
-            spec: type_spec_to_string(typedef)
+            spec: format_type_spec(typedef)
           }
         end
     end

test/elixir_sense/signature_test.exs

@@ -119,13 +119,56 @@ defmodule ElixirSense.SignatureTest do
                    documentation: "Remote type",
                    name: "remote_t",
                    params: [],
-                   spec: "@type remote_t :: atom"
+                   spec: "@type remote_t() :: atom()"
                  },
                  %{
                    documentation: "Remote type with params",
                    name: "remote_t",
                    params: ["a", "b"],
-                   spec: "@type remote_t(a, b) :: {a, b}"
+                   spec: "@type remote_t(a, b) ::\n  {a, b}"
+                 }
+               ]
+             }
+    end
+
+    test "does not reveal opaque type details" do
+      code = """
+      defmodule MyModule do
+        @type a :: ElixirSenseExample.ModuleWithTypespecs.Remote.some_opaque_options_t(
+      end
+      """
+
+      assert ElixirSense.signature(code, 2, 82) == %{
+               active_param: 0,
+               signatures: [
+                 %{
+                   documentation: "",
+                   name: "some_opaque_options_t",
+                   params: [],
+                   spec: "@opaque some_opaque_options_t()"
+                 }
+               ]
+             }
+    end
+
+    test "does not reveal local opaque type details" do
+      code = """
+      defmodule Some do
+        @opaque my(a, b) :: {a, b}
+      end
+      defmodule MyModule do
+        @type a :: Some.my(
+      end
+      """
+
+      assert ElixirSense.signature(code, 5, 22) == %{
+               active_param: 0,
+               signatures: [
+                 %{
+                   documentation: "",
+                   name: "my",
+                   params: ["a", "b"],
+                   spec: "@opaque my(a, b)"
                  }
                ]
              }
@@ -145,7 +188,7 @@ defmodule ElixirSense.SignatureTest do
                    documentation: "",
                    name: "some_type_doc_false",
                    params: ~c"",
-                   spec: "@type some_type_doc_false :: integer"
+                   spec: "@type some_type_doc_false() :: integer()"
                  }
                ]
              }
@@ -175,7 +218,7 @@ defmodule ElixirSense.SignatureTest do
                    documentation: summary,
                    name: "time_unit",
                    params: [],
-                   spec: "@type time_unit ::" <> _
+                   spec: "@type time_unit() ::" <> _
                  }
                ]
              } = ElixirSense.signature(code, 2, 32)
@@ -593,7 +636,8 @@ defmodule ElixirSense.SignatureTest do
       end
       """
 
-      # TODO?
+      # TODO https://github.com/elixir-lsp/elixir_sense/issues/255
+      # Type system needs to handle function captures
       assert ElixirSense.signature(code, 3, 20) == :none
     end
 
@@ -605,7 +649,8 @@ defmodule ElixirSense.SignatureTest do
       end
       """
 
-      # TODO?
+      # TODO https://github.com/elixir-lsp/elixir_sense/issues/255
+      # Type system needs to handle function captures
       assert ElixirSense.signature(code, 3, 20) == :none
     end