Handle OTP links when generating OTP docs

lib/ex_doc/autolink.ex

@@ -79,13 +79,17 @@ defmodule ExDoc.Autolink do
   end
 
   @doc false
-  def tool(module) do
+  def tool(module, config) do
     if match?("Elixir." <> _, Atom.to_string(module)) do
       :ex_doc
     else
-      case app_info(module) do
-        {true, _} -> :otp
-        {false, _} -> :ex_doc
+      {otp, app} = app_info(module)
+      apps = Enum.uniq(config.apps ++ Keyword.keys(config.deps))
+
+      if otp == true and app not in apps do
+        :otp
+      else
+        :ex_doc
       end
     end
   end

lib/ex_doc/language/elixir.ex

@@ -763,7 +763,7 @@ defmodule ExDoc.Language.Elixir do
 
     case {mode, Refs.get_visibility(ref)} do
       {_link_type, :public} ->
-        Autolink.app_module_url(Autolink.tool(module), module, config)
+        Autolink.app_module_url(Autolink.tool(module, config), module, config)
 
       {:regular_link, :undefined} ->
         nil
@@ -798,7 +798,7 @@ defmodule ExDoc.Language.Elixir do
 
     case {kind, visibility} do
       {_kind, :public} ->
-        fragment(Autolink.tool(module), kind, name, arity)
+        fragment(Autolink.tool(module, config), kind, name, arity)
 
       {:function, _visibility} ->
         try_autoimported_function(name, arity, mode, config, original_text)
@@ -829,7 +829,7 @@ defmodule ExDoc.Language.Elixir do
 
     case {mode, Refs.get_visibility({:module, module}), Refs.get_visibility(ref)} do
       {_mode, _module_visibility, :public} ->
-        case Autolink.tool(module) do
+        case Autolink.tool(module, config) do
           :no_tool ->
             nil
 

lib/ex_doc/language/erlang.ex

@@ -353,7 +353,7 @@ defmodule ExDoc.Language.Erlang do
   end
 
   defp final_url({:module, module}, config) do
-    tool = Autolink.tool(module)
+    tool = Autolink.tool(module, config)
     Autolink.app_module_url(tool, module, config)
   end
 
@@ -362,9 +362,11 @@ defmodule ExDoc.Language.Erlang do
   end
 
   defp final_url({kind, module, name, arity}, config) do
-    tool = Autolink.tool(module)
+    tool = Autolink.tool(module, config)
     module_url = Autolink.app_module_url(tool, module, config)
-    module_url && module_url <> fragment(tool, kind, name, arity)
+    # TODO: fix me
+    module_url = String.trim_trailing(module_url, "#content")
+    module_url <> fragment(tool, kind, name, arity)
   end
 
   defp fragment(:otp, :function, name, arity) do
@@ -379,11 +381,15 @@ defmodule ExDoc.Language.Erlang do
     "#type-#{name}"
   end
 
-  defp fragment(_, :function, name, arity) do
+  defp fragment(:ex_doc, :function, name, arity) do
     "##{name}/#{arity}"
   end
 
-  defp fragment(_, :type, name, arity) do
+  defp fragment(:ex_doc, :callback, name, arity) do
+    "#c:#{name}/#{arity}"
+  end
+
+  defp fragment(:ex_doc, :type, name, arity) do
     "#t:#{name}/#{arity}"
   end
 

test/ex_doc/language/erlang_test.exs

@@ -22,6 +22,11 @@ defmodule ExDoc.Language.ErlangTest do
                ~s|<a href="https://erlang.org/doc/man/array.html"><code>array</code></a>|
     end
 
+    test "OTP module when generating OTP docs", c do
+      assert autolink_doc("{@link array}", [deps: [stdlib: "https://example.com/stdlib"]], c) ==
+               ~s|<a href="https://example.com/stdlib/array.html"><code>array</code></a>|
+    end
+
     test "app module", c do
       assert autolink_doc("{@link //stdlib/array}", c) ==
                ~s|<a href="https://erlang.org/doc/man/array.html"><code>array</code></a>|
@@ -73,6 +78,16 @@ defmodule ExDoc.Language.ErlangTest do
                ~s|<a href="https://erlang.org/doc/man/array.html#new-0"><code>array:new/0</code></a>|
     end
 
+    test "OTP function when generating OTP docs", c do
+      assert autolink_doc("{@link array:new/0}", [apps: [:stdlib]], c) ==
+               ~s|<a href="array.html#new/0"><code>array:new/0</code></a>|
+    end
+
+    test "OTP function when generating OTP docs, same module", c do
+      assert autolink_doc("{@link array:new/0}", [current_module: :array, apps: [:stdlib]], c) ==
+               ~s|<a href="array.html#new/0"><code>array:new/0</code></a>|
+    end
+
     test "ERTS function", c do
       assert autolink_doc("{@link zlib:gunzip/1}", c) ==
                ~s|<a href="https://erlang.org/doc/man/zlib.html#gunzip-1"><code>zlib:gunzip/1</code></a>|
@@ -83,6 +98,8 @@ defmodule ExDoc.Language.ErlangTest do
                ~s|<a href="https://erlang.org/doc/man/array.html#new-0"><code>array:new/0</code></a>|
     end
 
+    # TODO: test callbacks. No support in EDoc, use :docgen_xml_to_chunks.
+
     test "external function", c do
       assert autolink_doc("{@link 'Elixir.EarmarkParser':as_ast/2}", c) ==
                ~s|<a href="https://hexdocs.pm/earmark_parser/EarmarkParser.html#as_ast/2"><code>'Elixir.EarmarkParser':as_ast/2</code></a>|