fixes bug Admin Mailer trends mail not displayed correctly (#39122)

app/mailers/admin_mailer.rb

@@ -34,9 +34,13 @@ class AdminMailer < ApplicationMailer
   end
 
   def new_trends(links, tags, statuses)
-    @links                  = links
-    @tags                   = tags
-    @statuses               = statuses
+    ActiveRecord::Associations::Preloader.new(records: [*links, *tags, *statuses], associations: [:trend]).call
+
+    @links                  = links.filter { |link| link.trend.present? }
+    @tags                   = tags.filter { |tag| tag.trend.present? }
+    @statuses               = statuses.filter { |status| status.trend.present? }
+
+    return unless @links.any? || @tags.any? || @statuses.any?
 
     mail subject: default_i18n_subject(instance: @instance)
   end

config/sidekiq.yml

@@ -17,7 +17,7 @@
       class: Scheduler::ScheduledStatusesScheduler
       queue: scheduler
     trends_refresh_scheduler:
-      every: '5m'
+      every: ['5m', first_in: '4m']
       class: Scheduler::Trends::RefreshScheduler
       queue: scheduler
     trends_review_notifications_scheduler:

spec/mailers/admin_mailer_spec.rb

@@ -71,16 +71,22 @@ RSpec.describe AdminMailer do
 
   describe '.new_trends' do
     let(:recipient) { Fabricate(:account, username: 'Snurf') }
-    let(:link) { Fabricate(:preview_card, trendable: true, language: 'en') }
-    let(:status) { Fabricate(:status) }
-    let(:tag) { Fabricate(:tag) }
-    let(:mail) { described_class.with(recipient: recipient).new_trends([link], [tag], [status]) }
+    let!(:link) { Fabricate(:preview_card, trendable: true, language: 'en') }
+    let!(:status) { Fabricate(:status) }
+    let!(:tag) { Fabricate(:tag, display_name: 'Test Tag') }
+    let!(:other_tag) { Fabricate(:tag, display_name: 'Test Tag') }
+    let!(:another_tag) { Fabricate(:tag, display_name: 'Test Tag') }
+    let(:mail) { described_class.with(recipient: recipient).new_trends([link], [tag, other_tag, another_tag], [status]) }
+    let(:status_trend) { Fabricate(:status_trend, status: status, account: Fabricate(:account)) }
+    let(:tag_trend) { Fabricate(:tag_trend, tag: tag) }
+    let(:other_tag_trend) { Fabricate(:tag_trend, tag: other_tag) }
+    let(:preview_card_trend) { Fabricate(:preview_card_trend, preview_card: link) }
 
     before do
-      PreviewCardTrend.create!(preview_card: link)
-      StatusTrend.create!(status: status, account: Fabricate(:account))
-      TagTrend.create!(tag: tag)
       recipient.user.update(locale: :en)
+      status_trend
+      tag_trend
+      preview_card_trend
     end
 
     it 'renders the email' do
@@ -96,6 +102,41 @@ RSpec.describe AdminMailer do
         .and match(link.title)
         .and match(tag.display_name)
     end
+
+    context 'when between queueing and sending trends gets deleted' do
+      let(:queue_mail) { described_class.with(recipient: recipient).new_trends([link], [tag, other_tag], [status]).deliver_later! }
+
+      before do
+        recipient.user.update(locale: :en)
+      end
+
+      it 'sends the email when all but one trends were deleted without the respective tag or status or link' do
+        other_tag_trend
+        expect(queue_mail.successfully_enqueued?).to be(true)
+
+        TagTrend.delete_all
+        StatusTrend.delete_all
+        expect { queue_mail.perform_now }.to send_email(
+          to: recipient.user_email,
+          from: 'notifications@localhost',
+          subject: I18n.t('admin_mailer.new_trends.subject', instance: Rails.configuration.x.local_domain)
+        )
+        expect(mail.body).to have_text(/The following items need a review before they can be displayed publicly/)
+          .and match(link.title)
+        expect(mail.body).to_not match(ActivityPub::TagManager.instance.url_for(status))
+        expect(mail.body).to_not match(tag.display_name)
+      end
+
+      it 'returns nil when no trends are present' do
+        expect(queue_mail.successfully_enqueued?).to be(true)
+
+        TagTrend.delete_all
+        StatusTrend.delete_all
+        PreviewCardTrend.delete_all
+
+        expect { queue_mail.perform_now }.to_not send_email
+      end
+    end
   end
 
   describe '.new_software_updates' do