Add equiv handling for types and callbacks for Erlang (#1873)

Author: garazdawi

Diff for: lib/ex_doc/language/erlang.ex

@@ -69,6 +69,36 @@ defmodule ExDoc.Language.Erlang do
     end
   end
 
+  defp equiv_data(module, file, line, metadata, prefix \\ "") do
+    case metadata[:equiv] do
+      nil ->
+        nil
+
+      equiv when is_binary(equiv) ->
+        ## We try to parse the equiv in order to link to the target
+        with {:ok, toks, _} <- :erl_scan.string(:unicode.characters_to_list(equiv <> ".")),
+             {:ok, [{:call, _, {:atom, _, func}, args}]} <- :erl_parse.parse_exprs(toks) do
+          "Equivalent to [`#{equiv}`](`#{prefix}#{func}/#{length(args)}`)."
+        else
+          {:ok, [{:op, _, :/, {:atom, _, _}, {:integer, _, _}}]} ->
+            "Equivalent to `#{prefix}#{equiv}`."
+
+          _ ->
+            "Equivalent to `#{equiv}`."
+        end
+        |> ExDoc.DocAST.parse!("text/markdown")
+
+      equiv ->
+        ExDoc.Utils.warn("invalid equiv #{inspect(equiv)}",
+          file: file,
+          line: line,
+          module: module
+        )
+
+        nil
+    end
+  end
+
   defp function_data(name, arity, _doc_content, module_data, metadata) do
     specs =
       case Map.fetch(module_data.private.specs, {name, arity}) do
@@ -88,26 +118,7 @@ defmodule ExDoc.Language.Erlang do
     {file, line} = Source.get_function_location(module_data, {name, arity})
 
     %{
-      doc_fallback: fn ->
-        case metadata[:equiv] do
-          nil ->
-            nil
-
-          equiv when is_binary(equiv) ->
-            ## We try to parse the equiv in order to link to the target
-            with {:ok, toks, _} <- :erl_scan.string(:unicode.characters_to_list(equiv <> ".")),
-                 {:ok, [{:call, _, {:atom, _, func}, args}]} <- :erl_parse.parse_exprs(toks) do
-              "Equivalent to [`#{equiv}`](`#{func}/#{length(args)}`)"
-            else
-              _ -> "Equivalent to `#{equiv}`"
-            end
-            |> ExDoc.DocAST.parse!("text/markdown")
-
-          equiv ->
-            IO.warn("invalid equiv: #{inspect(equiv)}", [])
-            nil
-        end
-      end,
+      doc_fallback: fn -> equiv_data(module_data.module, file, line, metadata) end,
       extra_annotations: [],
       source_line: line,
       source_file: file,
@@ -117,7 +128,7 @@ defmodule ExDoc.Language.Erlang do
 
   @impl true
   def callback_data(entry, module_data) do
-    {{_kind, name, arity}, anno, signature, _doc, _metadata} = entry
+    {{_kind, name, arity}, anno, signature, _doc, metadata} = entry
 
     extra_annotations =
       if {name, arity} in module_data.private.optional_callbacks, do: ["optional"], else: []
@@ -132,6 +143,15 @@ defmodule ExDoc.Language.Erlang do
       end
 
     %{
+      doc_fallback: fn ->
+        equiv_data(
+          module_data.module,
+          Source.anno_file(anno),
+          Source.anno_line(anno),
+          metadata,
+          "c:"
+        )
+      end,
       source_line: Source.anno_line(anno),
       source_file: Source.anno_file(anno),
       signature: signature,
@@ -142,11 +162,14 @@ defmodule ExDoc.Language.Erlang do
 
   @impl true
   def type_data(entry, module_data) do
-    {{kind, name, arity}, anno, signature, _doc, _metadata} = entry
+    {{kind, name, arity}, anno, signature, _doc, metadata} = entry
 
     case Source.get_type_from_module_data(module_data, name, arity) do
       %{} = map ->
         %{
+          doc_fallback: fn ->
+            equiv_data(module_data.module, map.source_file, map.source_line, metadata, "t:")
+          end,
           type: map.type,
           source_line: map.source_line,
           source_file: map.source_file,
@@ -157,6 +180,9 @@ defmodule ExDoc.Language.Erlang do
 
       nil ->
         %{
+          doc_fallback: fn ->
+            equiv_data(module_data.module, nil, Source.anno_line(anno), metadata, "t:")
+          end,
           type: kind,
           source_line: Source.anno_line(anno),
           spec: nil,

Diff for: lib/ex_doc/retriever.ex

@@ -341,7 +341,9 @@ defmodule ExDoc.Retriever do
       annotations_for_docs.(metadata) ++
         callback_data.extra_annotations ++ annotations_from_metadata(metadata, module_metadata)
 
-    doc_ast = doc_ast(content_type, source_doc, file: doc_file, line: doc_line + 1)
+    doc_ast =
+      doc_ast(content_type, source_doc, file: doc_file, line: doc_line + 1) ||
+        doc_fallback(callback_data)
 
     group =
       GroupMatcher.match_function(
@@ -401,7 +403,9 @@ defmodule ExDoc.Retriever do
         annotations_from_metadata(metadata, module_metadata) ++
         type_data.extra_annotations
 
-    doc_ast = doc_ast(content_type, source_doc, file: doc_file, line: doc_line + 1)
+    doc_ast =
+      doc_ast(content_type, source_doc, file: doc_file, line: doc_line + 1) ||
+        doc_fallback(type_data)
 
     group =
       GroupMatcher.match_function(
@@ -429,6 +433,10 @@ defmodule ExDoc.Retriever do
 
   ## General helpers
 
+  defp doc_fallback(data) do
+    data[:doc_fallback] && data.doc_fallback.()
+  end
+
   defp nil_or_name(name, arity) do
     if name == nil do
       "nil/#{arity}"

Diff for: lib/mix/tasks/docs.ex

@@ -245,7 +245,9 @@ defmodule Mix.Tasks.Docs do
   Functions and callbacks inside a module can also be organized in groups.
   This is done via the `:groups_for_docs` configuration which is a
   keyword list of group titles and filtering functions that receive the
-  documentation metadata of functions as argument.
+  documentation metadata of functions as argument. The metadata received will also
+  contain `:module`, `:name`, `:arity` and `:kind` to help identify which entity is
+  currently being processed.
 
   For example, imagine that you have an API client library with a large surface
   area for all the API endpoints you need to support. It would be helpful to

Diff for: test/ex_doc/retriever/erlang_test.exs

@@ -33,14 +33,17 @@ defmodule ExDoc.Retriever.ErlangTest do
       erlc(c, :mod, ~S"""
       -module(mod).
       -moduledoc("mod docs.").
-      -export([function1/0, function2/0]).
+      -export([function1/0, function2/1, equiv_function2/0]).
 
       -doc("function1/0 docs.").
       -spec function1() -> atom().
       function1() -> ok.
 
-      -doc("function2/0 docs.").
-      function2() -> ok.
+      -doc("function2/1 docs.").
+      function2(Opts) -> Opts.
+
+      -doc #{ equiv => function2([{test, args}]) }.
+      equiv_function2() -> function2([{test, args}]).
       """)
 
       {[mod], []} = Retriever.docs_from_modules([:mod], %ExDoc.Config{})
@@ -49,7 +52,7 @@ defmodule ExDoc.Retriever.ErlangTest do
         deprecated: nil,
         moduledoc_line: 2,
         moduledoc_file: moduledoc_file,
-        docs: [function1, function2],
+        docs: [equiv_function2, function1, function2],
         docs_groups: [:Types, :Callbacks, :Functions],
         group: nil,
         id: "mod",
@@ -93,11 +96,18 @@ defmodule ExDoc.Retriever.ErlangTest do
                "function1() -> <a href=\"https://www.erlang.org/doc/man/erlang.html#type-atom\">atom</a>()."
 
       %ExDoc.FunctionNode{
-        id: "function2/0"
+        id: "function2/1"
       } = function2
 
-      assert DocAST.to_string(function2.doc) =~ "function2/0 docs."
+      assert DocAST.to_string(function2.doc) =~ "function2/1 docs."
       assert function2.specs == []
+
+      %ExDoc.FunctionNode{
+        id: "equiv_function2/0"
+      } = equiv_function2
+
+      assert DocAST.to_string(equiv_function2.doc) =~
+               ~r'Equivalent to <a href="`function2/1`"><code[^>]+>function2\(\[\{test, args\}\]\).*\.'
     end
 
     test "module included files", c do
@@ -222,6 +232,9 @@ defmodule ExDoc.Retriever.ErlangTest do
       -doc("callback1/0 docs.").
       -callback callback1() -> atom().
 
+      -doc #{ equiv => callback1() }.
+      -callback equiv_callback1() -> atom().
+
       -doc("optional_callback1/0 docs.").
       -callback optional_callback1() -> atom().
 
@@ -230,7 +243,7 @@ defmodule ExDoc.Retriever.ErlangTest do
 
       config = %ExDoc.Config{source_url_pattern: "%{path}:%{line}"}
       {[mod], []} = Retriever.docs_from_modules([:mod], config)
-      [callback1, optional_callback1] = mod.docs
+      [callback1, equiv_callback1, optional_callback1] = mod.docs
 
       assert callback1.id == "c:callback1/0"
       assert callback1.type == :callback
@@ -242,6 +255,16 @@ defmodule ExDoc.Retriever.ErlangTest do
       assert Erlang.autolink_spec(hd(callback1.specs), current_kfa: {:callback, :callback1, 0}) ==
                "callback1() -> <a href=\"https://www.erlang.org/doc/man/erlang.html#type-atom\">atom</a>()."
 
+      assert equiv_callback1.id == "c:equiv_callback1/0"
+      assert equiv_callback1.type == :callback
+      assert equiv_callback1.annotations == []
+      assert equiv_callback1.group == :Callbacks
+
+      assert DocAST.to_string(equiv_callback1.doc) =~
+               ~r'Equivalent to <a href="`c:callback1/0`"><code[^>]+>callback1().*\.'
+
+      assert Path.basename(equiv_callback1.source_url) == "mod.erl:7"
+
       assert optional_callback1.id == "c:optional_callback1/0"
       assert optional_callback1.type == :callback
       assert optional_callback1.group == :Callbacks
@@ -251,18 +274,21 @@ defmodule ExDoc.Retriever.ErlangTest do
     test "types", c do
       erlc(c, :mod, ~S"""
       -module(mod).
-      -export_type([type1/0, opaque1/0]).
+      -export_type([type1/0, equiv_type1/0, opaque1/0]).
 
       -doc("type1/0 docs.").
       -type type1() :: atom().
 
+      -doc #{ equiv => type1/1 }.
+      -type equiv_type1() :: atom().
+
       -doc("opaque1/0 docs.").
       -opaque opaque1() :: atom().
       """)
 
       config = %ExDoc.Config{source_url_pattern: "%{path}:%{line}"}
       {[mod], []} = Retriever.docs_from_modules([:mod], config)
-      [opaque1, type1] = mod.typespecs
+      [equiv_type1, opaque1, type1] = mod.typespecs
 
       assert opaque1.id == "t:opaque1/0"
       assert opaque1.type == :opaque
@@ -281,6 +307,12 @@ defmodule ExDoc.Retriever.ErlangTest do
 
       assert type1.spec |> Erlang.autolink_spec(current_kfa: {:type, :type1, 0}) ==
                "type1() :: <a href=\"https://www.erlang.org/doc/man/erlang.html#type-atom\">atom</a>()."
+
+      assert equiv_type1.id == "t:equiv_type1/0"
+      assert equiv_type1.type == :type
+      assert equiv_type1.group == :Types
+      assert equiv_type1.signature == "equiv_type1()"
+      assert equiv_type1.doc |> DocAST.to_string() =~ ~r'Equivalent to .*t:type1/1.*\.'
     end
 
     test "records", c do