Fix tracking of issue weight change events

We cannot use an after_save hook here because the records are inserted
using bulk_insert

ee/app/models/resource_weight_event.rb

@@ -4,12 +4,4 @@ class ResourceWeightEvent < ResourceEvent
   include IssueResourceEvent
 
   validates :issue, presence: true
-
-  after_save :usage_metrics
-
-  private
-
-  def usage_metrics
-    Gitlab::UsageDataCounters::IssueActivityUniqueCounter.track_issue_weight_changed_action(author: user)
-  end
 end

ee/app/services/ee/issuable/common_system_notes_service.rb

@@ -42,7 +42,7 @@ module EE
       def handle_weight_change
         return unless issuable.previous_changes.include?('weight')
 
-        ::ResourceEvents::ChangeWeightService.new([issuable], current_user, Time.current).execute
+        ::ResourceEvents::ChangeWeightService.new(issuable, current_user, Time.current).execute
       end
 
       def handle_health_status_change

ee/app/services/ee/resource_events/change_weight_service.rb

-# frozen_string_literal: true
-
-module EE
-  module ResourceEvents
-    class ChangeWeightService
-      attr_reader :resources, :user, :event_created_at
-
-      def initialize(resources, user, created_at)
-        @resources = resources
-        @user = user
-        @event_created_at = created_at
-      end
-
-      def execute
-        unless resource_weight_changes.empty?
-          ::Gitlab::Database.bulk_insert(ResourceWeightEvent.table_name, resource_weight_changes) # rubocop:disable Gitlab/BulkInsert
-          resources.each(&:expire_note_etag_cache)
-        end
-      end
-
-      private
-
-      def resource_weight_changes
-        @weight_changes ||= resources.map do |resource|
-          changes = []
-          base_data = { user_id: user.id, issue_id: resource.id }
-
-          changes << base_data.merge({ weight: resource.previous_weight, created_at: resource.previous_updated_at }) if resource.first_weight_event?
-          changes << base_data.merge({ weight: resource.weight, created_at: event_created_at })
-        end.flatten
-      end
-    end
-  end
-end

ee/app/services/resource_events/change_weight_service.rb

@@ -2,31 +2,31 @@
 
 module ResourceEvents
   class ChangeWeightService
-    attr_reader :resources, :user, :event_created_at
+    attr_reader :resource, :user, :event_created_at
 
-    def initialize(resources, user, created_at)
-      @resources = resources
+    def initialize(resource, user, created_at)
+      @resource = resource
       @user = user
       @event_created_at = created_at
     end
 
     def execute
-      unless resource_weight_changes.empty?
-        ::Gitlab::Database.bulk_insert(ResourceWeightEvent.table_name, resource_weight_changes) # rubocop:disable Gitlab/BulkInsert
-        resources.each(&:expire_note_etag_cache)
-      end
+      ::Gitlab::Database.bulk_insert(ResourceWeightEvent.table_name, resource_weight_changes) # rubocop:disable Gitlab/BulkInsert
+      resource.expire_note_etag_cache
+
+      Gitlab::UsageDataCounters::IssueActivityUniqueCounter.track_issue_weight_changed_action(author: user)
     end
 
     private
 
     def resource_weight_changes
-      @weight_changes ||= resources.map do |resource|
-        changes = []
-        base_data = { user_id: user.id, issue_id: resource.id }
+      changes = []
+      base_data = { user_id: user.id, issue_id: resource.id }
+
+      changes << base_data.merge({ weight: resource.previous_weight, created_at: resource.previous_updated_at }) if resource.first_weight_event?
+      changes << base_data.merge({ weight: resource.weight, created_at: event_created_at })
 
-        changes << base_data.merge({ weight: resource.previous_weight, created_at: resource.previous_updated_at }) if resource.first_weight_event?
-        changes << base_data.merge({ weight: resource.weight, created_at: event_created_at })
-      end.flatten
+      changes
     end
   end
 end

ee/spec/models/resource_weight_event_spec.rb

@@ -73,14 +73,4 @@ RSpec.describe ResourceWeightEvent, type: :model do
       expect(event.discussion_id).to eq('73d167c478')
     end
   end
-
-  context 'callbacks' do
-    describe '#usage_metrics' do
-      it 'tracks changed weights' do
-        expect(Gitlab::UsageDataCounters::IssueActivityUniqueCounter).to receive(:track_issue_weight_changed_action).with(author: user1)
-
-        create(:resource_weight_event, issue: issue1, user: user1)
-      end
-    end
-  end
 end

ee/spec/services/resource_events/change_weight_service_spec.rb

@@ -8,7 +8,7 @@ RSpec.describe ResourceEvents::ChangeWeightService do
   let(:issue) { create(:issue, weight: 3) }
   let(:created_at_time) { Time.utc(2019, 1, 1, 12, 30, 48, '123.123'.to_r) }
 
-  subject { described_class.new([issue], user, created_at_time).execute }
+  subject { described_class.new(issue, user, created_at_time).execute }
 
   before do
     ResourceWeightEvent.new(issue: issue, user: user).save!
@@ -51,31 +51,16 @@ RSpec.describe ResourceEvents::ChangeWeightService do
     end
   end
 
+  it 'tracks issue usage data counters' do
+    expect(Gitlab::UsageDataCounters::IssueActivityUniqueCounter).to receive(:track_issue_weight_changed_action).with(author: user)
+
+    subject
+  end
+
   def expect_event_record(record, weight:, created_at:)
     expect(record.issue).to eq(issue)
     expect(record.user).to eq(user)
     expect(record.weight).to eq(weight)
     expect(record.created_at).to be_like_time(created_at)
   end
-
-  describe 'bulk issue weight updates' do
-    let(:issues) { create_list(:issue, 3, weight: 1) }
-
-    before do
-      issues.each { |issue| issue.update!(weight: 3) }
-    end
-
-    it 'bulk insert weight changes' do
-      expect do
-        described_class.new(issues, user, created_at_time).execute
-      end.to change { ResourceWeightEvent.count }.by(6)
-    end
-
-    it 'calls first_weight_event? once per resource' do
-      service = described_class.new(issues, user, created_at_time)
-      allow(service).to receive(:first_weight_event?).exactly(3).times
-
-      service.execute
-    end
-  end
 end