Skip Erlang functions that have empty docs (#1384)

lib/ex_doc/language.ex

@@ -46,7 +46,7 @@ defmodule ExDoc.Language do
   @callback module_data(module(), tuple(), ExDoc.Config.t()) :: module_data() | :skip
 
   @doc """
-  Returns a map with function information.
+  Returns a map with function information or an atom `:skip`.
 
   The map has the following keys:
 
@@ -67,6 +67,7 @@ defmodule ExDoc.Language do
                 line: non_neg_integer() | nil,
                 specs: [spec_ast()]
               }
+              | :skip
 
   @doc """
   Returns a map with callback information.
@@ -83,12 +84,13 @@ defmodule ExDoc.Language do
     * `:specs` - a list of specs that will be later formatted by `c:typespec/2`
 
   """
-  @callback callback_data(entry :: tuple(), module_data()) :: %{
-              actual_def: {atom(), arity()},
-              line: non_neg_integer() | nil,
-              signature: [binary()],
-              specs: [spec_ast()]
-            }
+  @callback callback_data(entry :: tuple(), module_data()) ::
+              %{
+                actual_def: {atom(), arity()},
+                line: non_neg_integer() | nil,
+                signature: [binary()],
+                specs: [spec_ast()]
+              }
 
   @doc """
   Returns a map with type information.
@@ -103,12 +105,13 @@ defmodule ExDoc.Language do
 
     * `:spec` - a spec that will be later formatted by `c:typespec/2`
   """
-  @callback type_data(entry :: tuple(), spec :: term()) :: %{
-              type: :type | :opaque,
-              line: non_neg_integer(),
-              signature: [binary()],
-              spec: spec_ast()
-            }
+  @callback type_data(entry :: tuple(), spec :: term()) ::
+              %{
+                type: :type | :opaque,
+                line: non_neg_integer(),
+                signature: [binary()],
+                spec: spec_ast()
+              }
 
   @doc """
   Autolinks docs.

lib/ex_doc/language/elixir.ex

@@ -42,8 +42,16 @@ defmodule ExDoc.Language.Elixir do
 
   @impl true
   def function_data(entry, module_data) do
-    {{kind, name, arity}, _anno, _signature, _doc_content, metadata} = entry
+    {{kind, name, arity}, _anno, _signature, doc_content, metadata} = entry
 
+    if doc?(entry, module_data.type) do
+      function_data(kind, name, arity, doc_content, metadata, module_data)
+    else
+      :skip
+    end
+  end
+
+  def function_data(kind, name, arity, _doc_content, metadata, module_data) do
     extra_annotations =
       case {kind, name, arity} do
         {:macro, _, _} -> ["macro"]
@@ -66,6 +74,33 @@ defmodule ExDoc.Language.Elixir do
     }
   end
 
+  # We are only interested in functions and macros for now
+  defp doc?({{kind, _, _}, _, _, _, _}, _) when kind not in [:function, :macro] do
+    false
+  end
+
+  # Skip impl_for and impl_for! for protocols
+  defp doc?({{_, name, _}, _, _, _, _}, :protocol) when name in [:impl_for, :impl_for!] do
+    false
+  end
+
+  # If content is a map, then it is ok.
+  defp doc?({_, _, _, %{}, _}, _) do
+    true
+  end
+
+  # We keep this clause with backwards compatibility with Elixir,
+  # from v1.12+, functions not starting with _ always default to %{}.
+  # TODO: Remove me once we require Elixir v1.12.
+  defp doc?({{_, name, _}, _, _, :none, _}, _type) do
+    hd(Atom.to_charlist(name)) != ?_
+  end
+
+  # Everything else is hidden.
+  defp doc?({_, _, _, _, _}, _) do
+    false
+  end
+
   @impl true
   def callback_data(entry, module_data) do
     {{kind, name, arity}, anno, _signature, _doc, _metadata} = entry

lib/ex_doc/language/erlang.ex

@@ -6,11 +6,17 @@ defmodule ExDoc.Language.Erlang do
   alias ExDoc.{Autolink, Refs}
 
   @impl true
-  def module_data(_module, {:docs_v1, _, _, _, doc, _, _}, _config) when not is_map(doc) do
-    :skip
+  def module_data(module, docs_chunk, _config) do
+    {:docs_v1, _, _, _, doc, _, _} = docs_chunk
+
+    if is_map(doc) do
+      module_data(module, docs_chunk)
+    else
+      :skip
+    end
   end
 
-  def module_data(module, docs_chunk, _config) do
+  def module_data(module, docs_chunk) do
     ":" <> id = inspect(module)
     abst_code = get_abstract_code(module)
     line = find_module_line(module, abst_code)
@@ -35,8 +41,16 @@ defmodule ExDoc.Language.Erlang do
 
   @impl true
   def function_data(entry, module_data) do
-    {{_kind, name, arity}, _anno, _signature, _doc_content, _metadata} = entry
+    {{kind, name, arity}, _anno, _signature, doc_content, _metadata} = entry
+
+    if kind == :function and is_map(doc_content) do
+      function_data(name, arity, doc_content, module_data)
+    else
+      :skip
+    end
+  end
 
+  defp function_data(name, arity, _doc_content, module_data) do
     specs =
       case Map.fetch(module_data.private.specs, {name, arity}) do
         {:ok, specs} ->

lib/ex_doc/retriever.ex

@@ -166,49 +166,24 @@ defmodule ExDoc.Retriever do
 
   ## Function helpers
 
-  defp get_docs(%{type: type, docs: docs} = module_data, source, groups_for_functions) do
-    {:docs_v1, _, _, _, _, _, doc_elements} = docs
+  defp get_docs(module_data, source, groups_for_functions) do
+    {:docs_v1, _, _, _, _, _, doc_elements} = module_data.docs
 
-    function_doc_elements =
-      for doc_element <- doc_elements, doc?(doc_element, type) do
-        get_function(doc_element, source, module_data, groups_for_functions)
-      end
-
-    filter_defaults(function_doc_elements)
-  end
-
-  # TODO: Elixir specific
-  # We are only interested in functions and macros for now
-  defp doc?({{kind, _, _}, _, _, _, _}, _) when kind not in [:function, :macro] do
-    false
-  end
-
-  # TODO: Elixir specific
-  # Skip impl_for and impl_for! for protocols
-  defp doc?({{_, name, _}, _, _, _, _}, :protocol) when name in [:impl_for, :impl_for!] do
-    false
-  end
+    nodes =
+      Enum.flat_map(doc_elements, fn doc_element ->
+        case module_data.language.function_data(doc_element, module_data) do
+          :skip ->
+            []
 
-  # If content is a map, then it is ok.
-  defp doc?({_, _, _, %{}, _}, _) do
-    true
-  end
-
-  # We keep this clause with backwards compatibility with Elixir,
-  # from v1.12+, functions not starting with _ always default to %{}.
-  # TODO: Remove me once we require Elixir v1.12.
-  defp doc?({{_, name, _}, _, _, :none, _}, _type) do
-    hd(Atom.to_charlist(name)) != ?_
-  end
+          function_data ->
+            [get_function(doc_element, function_data, source, module_data, groups_for_functions)]
+        end
+      end)
 
-  # Everything else is hidden.
-  defp doc?({_, _, _, _, _}, _) do
-    false
+    filter_defaults(nodes)
   end
 
-  defp get_function(doc_element, source, module_data, groups_for_functions) do
-    function_data = module_data.language.function_data(doc_element, module_data)
-
+  defp get_function(doc_element, function_data, source, module_data, groups_for_functions) do
     {:docs_v1, _, _, content_type, _, _, _} = module_data.docs
     {{type, name, arity}, anno, signature, doc_content, metadata} = doc_element
     doc_line = anno_line(anno)
@@ -249,14 +224,14 @@ defmodule ExDoc.Retriever do
     for default <- (arity - defaults)..(arity - 1), do: {name, default}
   end
 
-  defp filter_defaults(docs) do
-    Enum.map(docs, &filter_defaults(&1, docs))
+  defp filter_defaults(nodes) do
+    Enum.map(nodes, &filter_defaults(&1, nodes))
   end
 
-  defp filter_defaults(doc, docs) do
-    update_in(doc.defaults, fn defaults ->
+  defp filter_defaults(node, nodes) do
+    update_in(node.defaults, fn defaults ->
       Enum.reject(defaults, fn {name, arity} ->
-        Enum.any?(docs, &match?(%{name: ^name, arity: ^arity}, &1))
+        Enum.any?(nodes, &match?(%{name: ^name, arity: ^arity}, &1))
       end)
     end)
   end

test/ex_doc/retriever/erlang_test.exs

@@ -85,6 +85,21 @@ defmodule ExDoc.Retriever.ErlangTest do
       [] = Retriever.docs_from_modules([:mod], %ExDoc.Config{})
     end
 
+    @tag :otp23
+    @tag :otp24
+    test "function with no docs is skipped", c do
+      erlc(c, :mod, ~S"""
+      %% @doc Docs.
+      -module(mod).
+      -export([f/0]).
+
+      f() -> ok.
+      """)
+
+      [mod] = Retriever.docs_from_modules([:mod], %ExDoc.Config{})
+      assert mod.docs == []
+    end
+
     @tag :otp24
     test "callbacks", c do
       erlc(c, :mod, ~S"""