Change profile updates to be sent to recently-mentioned servers (#24852)

app/lib/account_reach_finder.rb

@@ -6,7 +6,7 @@ class AccountReachFinder
   end
 
   def inboxes
-    (followers_inboxes + reporters_inboxes + relay_inboxes).uniq
+    (followers_inboxes + reporters_inboxes + recently_mentioned_inboxes + relay_inboxes).uniq
   end
 
   private
@@ -19,6 +19,13 @@ class AccountReachFinder
     Account.where(id: @account.targeted_reports.select(:account_id)).inboxes
   end
 
+  def recently_mentioned_inboxes
+    cutoff_id       = Mastodon::Snowflake.id_at(2.days.ago, with_random: false)
+    recent_statuses = @account.statuses.recent.where(id: cutoff_id...).limit(200)
+
+    Account.joins(:mentions).where(mentions: { status: recent_statuses }).inboxes.take(2000)
+  end
+
   def relay_inboxes
     Relay.enabled.pluck(:inbox_url)
   end

spec/lib/account_reach_finder_spec.rb

+# frozen_string_literal: true
+
+require 'rails_helper'
+
+RSpec.describe AccountReachFinder do
+  let(:account) { Fabricate(:account) }
+
+  let(:follower1) { Fabricate(:account, protocol: :activitypub, inbox_url: 'https://example.com/inbox-1') }
+  let(:follower2) { Fabricate(:account, protocol: :activitypub, inbox_url: 'https://example.com/inbox-2') }
+  let(:follower3) { Fabricate(:account, protocol: :activitypub, inbox_url: 'https://foo.bar/users/a/inbox', shared_inbox_url: 'https://foo.bar/inbox') }
+
+  let(:mentioned1) { Fabricate(:account, protocol: :activitypub, inbox_url: 'https://foo.bar/users/b/inbox', shared_inbox_url: 'https://foo.bar/inbox') }
+  let(:mentioned2) { Fabricate(:account, protocol: :activitypub, inbox_url: 'https://example.com/inbox-3') }
+  let(:mentioned3) { Fabricate(:account, protocol: :activitypub, inbox_url: 'https://example.com/inbox-4') }
+
+  let(:unrelated_account) { Fabricate(:account, protocol: :activitypub, inbox_url: 'https://example.com/unrelated-inbox') }
+
+  before do
+    follower1.follow!(account)
+    follower2.follow!(account)
+    follower3.follow!(account)
+
+    Fabricate(:status, account: account).tap do |status|
+      status.mentions << Mention.new(account: follower1)
+      status.mentions << Mention.new(account: mentioned1)
+    end
+
+    Fabricate(:status, account: account)
+
+    Fabricate(:status, account: account).tap do |status|
+      status.mentions << Mention.new(account: mentioned2)
+      status.mentions << Mention.new(account: mentioned3)
+    end
+
+    Fabricate(:status).tap do |status|
+      status.mentions << Mention.new(account: unrelated_account)
+    end
+  end
+
+  describe '#inboxes' do
+    it 'includes the preferred inbox URL of followers' do
+      expect(described_class.new(account).inboxes).to include(*[follower1, follower2, follower3].map(&:preferred_inbox_url))
+    end
+
+    it 'includes the preferred inbox URL of recently-mentioned accounts' do
+      expect(described_class.new(account).inboxes).to include(*[mentioned1, mentioned2, mentioned3].map(&:preferred_inbox_url))
+    end
+
+    it 'does not include the inbox of unrelated users' do
+      expect(described_class.new(account).inboxes).to_not include(unrelated_account.preferred_inbox_url)
+    end
+  end
+end