lib/pleroma/web/activity_pub/side_effects.ex

@@ -448,14 +448,29 @@ defp history_skeleton do
     "attachment",
     "generator"
   ]
-  defp handle_update_object(
-         %{data: %{"type" => "Update", "object" => updated_object}} = object,
-         meta
-       ) do
-    orig_object = Object.get_by_ap_id(updated_object["id"])
-    orig_object_data = orig_object.data
+  defp update_content_fields(orig_object_data, updated_object) do
+    @updatable_fields
+    |> Enum.reduce(
+      %{data: orig_object_data, updated: false},
+      fn field, %{data: data, updated: updated} ->
+        updated = updated or Map.get(updated_object, field) != Map.get(orig_object_data, field)
 
-    if orig_object_data["type"] in @updatable_object_types do
+        data =
+          if Map.has_key?(updated_object, field) do
+            Map.put(data, field, updated_object[field])
+          else
+            Map.drop(data, [field])
+          end
+
+        %{data: data, updated: updated}
+      end
+    )
+  end
+
+  defp maybe_update_history(updated_object, orig_object_data, updated) do
+    if not updated do
+      updated_object
+    else
       # Put edit history
       # Note that we may have got the edit history by first fetching the object
       history = history_for_object(orig_object_data)
@@ -469,19 +484,47 @@ defp handle_update_object(
         |> Map.put("orderedItems", [latest_history_item | history["orderedItems"]])
         |> Map.put("totalItems", history["totalItems"] + 1)
 
+      updated_object
+      |> Map.put("formerRepresentations", new_history)
+    end
+  end
+
+  defp maybe_update_poll(to_be_updated, updated_object) do
+    choice_key = fn data ->
+      if Map.has_key?(data, "anyOf"), do: "anyOf", else: "oneOf"
+    end
+
+    with true <- to_be_updated["type"] == "Question",
+         key <- choice_key.(updated_object),
+         true <- key == choice_key.(to_be_updated),
+         orig_choices <- to_be_updated[key] |> Enum.map(&Map.drop(&1, ["replies"])),
+         new_choices <- updated_object[key] |> Enum.map(&Map.drop(&1, ["replies"])),
+         true <- orig_choices == new_choices do
+      # Choices are the same, but counts are different
+      to_be_updated
+      |> Map.put(key, updated_object[key])
+    else
+      # Choices (or vote type) have changed, do not allow this
+      _ -> to_be_updated
+    end
+  end
+
+  defp handle_update_object(
+         %{data: %{"type" => "Update", "object" => updated_object}} = object,
+         meta
+       ) do
+    orig_object = Object.get_by_ap_id(updated_object["id"])
+    orig_object_data = orig_object.data
+
+    if orig_object_data["type"] in @updatable_object_types do
+      %{data: updated_object_data, updated: updated} =
+        orig_object_data
+        |> update_content_fields(updated_object)
+
       updated_object_data =
-        @updatable_fields
-        |> Enum.reduce(
-          orig_object_data,
-          fn field, acc ->
-            if Map.has_key?(updated_object, field) do
-              Map.put(acc, field, updated_object[field])
-            else
-              Map.drop(acc, [field])
-            end
-          end
-        )
-        |> Map.put("formerRepresentations", new_history)
+        updated_object_data
+        |> maybe_update_history(orig_object_data, updated)
+        |> maybe_update_poll(updated_object)
 
       orig_object
       |> Object.change(%{data: updated_object_data})

test/pleroma/web/activity_pub/side_effects_test.exs

@@ -183,15 +183,24 @@ test "it records the original note in formerRepresentations", %{
     end
 
     test "it puts the original note at the front of formerRepresentations", %{
+      user: user,
       note: note,
       object_id: object_id,
       update: update
     } do
       {:ok, _, _} = SideEffects.handle(update)
       %{data: first_edit} = Pleroma.Object.get_by_id(object_id)
+
+      second_updated_note =
+        note.data
+        |> Map.put("summary", "edited summary 2")
+        |> Map.put("content", "edited content 2")
+
+      {:ok, second_update_data, []} = Builder.update(user, second_updated_note)
+      {:ok, update, _meta} = ActivityPub.persist(second_update_data, local: true)
       {:ok, _, _} = SideEffects.handle(update)
       %{data: new_note} = Pleroma.Object.get_by_id(object_id)
-      assert %{"summary" => "edited summary", "content" => "edited content"} = new_note
+      assert %{"summary" => "edited summary 2", "content" => "edited content 2"} = new_note
 
       original_version = Map.drop(note.data, ["id", "formerRepresentations"])
       first_edit = Map.drop(first_edit, ["id", "formerRepresentations"])
@@ -201,6 +210,59 @@ test "it puts the original note at the front of formerRepresentations", %{
 
       assert new_note["formerRepresentations"]["totalItems"] == 2
     end
+
+    test "it does not prepend to formerRepresentations if no actual changes are made", %{
+      note: note,
+      object_id: object_id,
+      update: update
+    } do
+      {:ok, _, _} = SideEffects.handle(update)
+      %{data: _first_edit} = Pleroma.Object.get_by_id(object_id)
+
+      {:ok, _, _} = SideEffects.handle(update)
+      %{data: new_note} = Pleroma.Object.get_by_id(object_id)
+      assert %{"summary" => "edited summary", "content" => "edited content"} = new_note
+
+      original_version = Map.drop(note.data, ["id", "formerRepresentations"])
+
+      assert [original_version] ==
+               new_note["formerRepresentations"]["orderedItems"]
+
+      assert new_note["formerRepresentations"]["totalItems"] == 1
+    end
+  end
+
+  describe "update questions" do
+    setup do
+      user = insert(:user)
+      question = insert(:question, user: user)
+
+      %{user: user, data: question.data, id: question.id}
+    end
+
+    test "allows updating choice count without generating edit history", %{
+      user: user,
+      data: data,
+      id: id
+    } do
+      new_choices =
+        data["oneOf"]
+        |> Enum.map(fn choice -> put_in(choice, ["replies", "totalItems"], 5) end)
+
+      updated_question = data |> Map.put("oneOf", new_choices)
+
+      {:ok, update_data, []} = Builder.update(user, updated_question)
+      {:ok, update, _meta} = ActivityPub.persist(update_data, local: true)
+
+      {:ok, _, _} = SideEffects.handle(update)
+
+      %{data: new_question} = Pleroma.Object.get_by_id(id)
+
+      assert [%{"replies" => %{"totalItems" => 5}}, %{"replies" => %{"totalItems" => 5}}] =
+               new_question["oneOf"]
+
+      refute Map.has_key?(new_question, "formerRepresentations")
+    end
   end
 
   describe "EmojiReact objects" do