fix[Op#40437]: Reinstate emoji reactions streams

Journalsa are updated on last updated_at; reactions cannot rely on this as they do not "touch"
the journal, so a full journal refresh would not be viable. We avoid "touching" the journal on emoji
reactions update to retain concurrent user actions. E.g. If a user has a journal in edit mode, we do not want to overrite
it on the next polling update- this is why it's safer to stream emoji reactions separately

This reverts commit fb419dd.

app/components/work_packages/activities_tab/journals/item_component/reactions.html.erb

@@ -1,26 +1,28 @@
 <%=
   component_wrapper do
-    flex_layout(test_selector: "emoji-reactions") do |reactions_container|
-      grouped_emoji_reactions.each do |reaction, data|
-        reactions_container.with_column(mr: 2) do
-          render(Primer::Beta::Button.new(
-                  scheme: button_scheme(data[:users]),
-                  color: :default,
-                  bg: counter_color(data[:users]),
-                  id: "#{journal.id}-#{reaction}",
-                  test_selector: "reaction-#{reaction}",
-                  tag: :a,
-                  href: href(reaction:),
-                  data: { turbo_stream: true, turbo_method: :put },
-                  aria: { label: aria_label_text(reaction, data[:users]) },
-                  disabled: current_user_cannot_react?,
-                  classes: "op-reactions-button"
-                )) do |button|
-            button.with_tooltip(text: number_of_user_reactions_text(data[:users]),
-                                test_selector: "reaction-tooltip-#{reaction}") do
-              button.with_icon(EmojiReactions.emoji(reaction), size: :small)
+    if grouped_emoji_reactions.present?
+      flex_layout(test_selector: "emoji-reactions") do |reactions_container|
+        grouped_emoji_reactions.each do |reaction, data|
+          reactions_container.with_column(mr: 2) do
+            render(Primer::Beta::Button.new(
+                    scheme: button_scheme(data[:users]),
+                    color: :default,
+                    bg: counter_color(data[:users]),
+                    id: "#{journal.id}-#{reaction}",
+                    test_selector: "reaction-#{reaction}",
+                    tag: :a,
+                    href: href(reaction:),
+                    data: { turbo_stream: true, turbo_method: :put },
+                    aria: { label: aria_label_text(reaction, data[:users]) },
+                    disabled: current_user_cannot_react?,
+                    classes: "op-reactions-button"
+                  )) do |button|
+              button.with_tooltip(text: number_of_user_reactions_text(data[:users]),
+                                  test_selector: "reaction-tooltip-#{reaction}") do
+                button.with_icon(EmojiReactions.emoji(reaction), size: :small)
+              end
+              "#{EmojiReaction.emoji(reaction)} #{data[:count]}"
             end
-            "#{EmojiReaction.emoji(reaction)} #{data[:count]}"
           end
         end
       end

app/components/work_packages/activities_tab/journals/item_component/reactions.rb

@@ -41,10 +41,6 @@ def initialize(journal:, grouped_emoji_reactions:)
           @grouped_emoji_reactions = grouped_emoji_reactions
         end
 
-        def render?
-          grouped_emoji_reactions.present?
-        end
-
         private
 
         attr_reader :journal, :grouped_emoji_reactions

app/controllers/work_packages/activities_tab_controller.rb

@@ -256,6 +256,7 @@ def handle_other_filters_on_create(call)
   def perform_update_streams_from_last_update_timestamp
     if params[:last_update_timestamp].present? && (last_updated_at = Time.zone.parse(params[:last_update_timestamp]))
       generate_time_based_update_streams(last_updated_at)
+      generate_work_package_journals_emoji_reactions_update_streams
     else
       @turbo_status = :bad_request
     end
@@ -328,6 +329,18 @@ def generate_time_based_update_streams(last_update_timestamp)
     end
   end
 
+  def generate_work_package_journals_emoji_reactions_update_streams
+    # Current limitation: Only shows added reactions, not removed ones
+    Journal.grouped_work_package_journals_emoji_reactions(@work_package).each do |journal_id, grouped_emoji_reactions|
+      update_via_turbo_stream(
+        component: WorkPackages::ActivitiesTab::Journals::ItemComponent::Reactions.new(
+          journal: @work_package.journals.find(journal_id),
+          grouped_emoji_reactions:
+        )
+      )
+    end
+  end
+
   def rerender_updated_journals(journals, last_update_timestamp, grouped_emoji_reactions)
     journals.where("updated_at > ?", last_update_timestamp).find_each do |journal|
       update_item_show_component(journal:, grouped_emoji_reactions: grouped_emoji_reactions.fetch(journal.id, {}))

spec/components/work_packages/activities_tab/journals/item_component/reactions_spec.rb

@@ -61,10 +61,12 @@
   end
 
   context "with no reactions" do
-    it "does not render" do
+    it "renders just the component node" do
+      # NB: This is so that there is always a node to update during WorkPackages::ActivitiesTabController#update_streams polling
       render_inline(described_class.new(journal:, grouped_emoji_reactions: {}))
 
-      expect(page.text).to be_empty
+      component = page.find("#work-packages-activities-tab-journals-item-component-reactions-#{journal.id}")
+      expect(component.text).to be_empty
     end
   end
 

spec/features/activities/work_package/emoji_reactions_spec.rb

@@ -137,6 +137,48 @@
     end
   end
 
+  describe "reactions updates" do
+    let(:work_package) { create(:work_package, project:, author: admin) }
+    let(:first_comment_by_member) do
+      create(:work_package_journal, user: member, notes: "Second comment by member", journable: work_package,
+                                    version: 2)
+    end
+
+    current_user { member }
+
+    before do
+      # set WORK_PACKAGES_ACTIVITIES_TAB_POLLING_INTERVAL_IN_MS to 1000
+      # to speed up the polling interval for test duration
+      ENV["WORK_PACKAGES_ACTIVITIES_TAB_POLLING_INTERVAL_IN_MS"] = "1000"
+
+      wp_page.visit!
+      wp_page.wait_for_activity_tab
+    end
+
+    after do
+      ENV.delete("WORK_PACKAGES_ACTIVITIES_TAB_POLLING_INTERVAL_IN_MS")
+    end
+
+    it "shows the updated reactions without reload", :aggregate_failures do
+      activity_tab.expect_journal_notes(text: first_comment_by_member.notes)
+
+      # Simulate another user adding a reaction
+      EmojiReactions::CreateService
+         .new(user: admin)
+         .call(user: admin, reactable: first_comment_by_member, reaction: :confused_face)
+
+      wait_for do
+        activity_tab.expect_emoji_reactions_for_journal(first_comment_by_member, "😕" => 1)
+      end
+
+      # Current user adds several reactions
+      activity_tab.add_first_emoji_reaction_for_journal(first_comment_by_member, "👍")
+      activity_tab.add_emoji_reaction_for_journal(first_comment_by_member, "😕")
+
+      activity_tab.expect_emoji_reactions_for_journal(first_comment_by_member, "👍" => 1, "😕" => 2)
+    end
+  end
+
   def create_user_as_project_member
     member_role = create(:project_role,
                          permissions: %i[view_work_packages edit_work_packages add_work_packages work_package_assigned