Fix last_status_at not accurately tracking last status time for remote accounts (#37619)

app/models/concerns/account/counters.rb

@@ -20,8 +20,8 @@ module Account::Counters
            to: :account_stat
 
   # @param [Symbol] key
-  def increment_count!(key)
+  def increment_count!(key, status_created_at: nil)
-    update_count!(key, 1)
+    update_count!(key, 1, status_created_at:)
   end
 
   # @param [Symbol] key
@@ -31,11 +31,11 @@ module Account::Counters
 
   # @param [Symbol] key
   # @param [Integer] value
-  def update_count!(key, value)
+  def update_count!(key, value, status_created_at: nil)
     raise ArgumentError, "Invalid key #{key}" unless ALLOWED_COUNTER_KEYS.include?(key)
     raise ArgumentError, 'Do not call update_count! on dirty objects' if association(:account_stat).loaded? && account_stat&.changed? && account_stat.changed_attribute_names_to_save == %w(id)
 
-    result = updated_account_stat(key, value.to_i)
+    result = updated_account_stat(key, value.to_i, status_created_at:)
 
     # Reload account_stat if it was loaded, taking into account newly-created unsaved records
     if association(:account_stat).loaded?
@@ -50,25 +50,27 @@ module Account::Counters
 
   private
 
-  def updated_account_stat(key, value)
+  def updated_account_stat(key, value, status_created_at: nil)
+    status_created_at = Time.now.utc if status_created_at.nil? || status_created_at > Time.now.utc
+
     AccountStat.upsert(
-      initial_values(key, value),
+      initial_values(key, value, status_created_at:),
       on_duplicate: Arel.sql(
-        duplicate_values(key, value).join(', ')
+        duplicate_values(key, value, status_created_at:).join(', ')
       ),
       unique_by: :account_id
     )
   end
 
-  def initial_values(key, value)
+  def initial_values(key, value, status_created_at: nil)
     { :account_id => id, key => [value, 0].max }.tap do |values|
-      values.merge!(last_status_at: Time.current) if key == :statuses_count
+      values.merge!(last_status_at: status_created_at) if key == :statuses_count
     end
   end
 
-  def duplicate_values(key, value)
+  def duplicate_values(key, value, status_created_at: nil)
     ["#{key} = (account_stats.#{key} + #{value})", 'updated_at = CURRENT_TIMESTAMP'].tap do |values|
-      values << 'last_status_at = CURRENT_TIMESTAMP' if key == :statuses_count && value.positive?
+      values << AccountStat.sanitize_sql_array(['last_status_at = GREATEST(account_stats.last_status_at, ?::timestamp)', status_created_at]) if key == :statuses_count && value.positive?
     end
   end
 

app/models/status.rb

@@ -481,7 +481,7 @@ class Status < ApplicationRecord
   def increment_counter_caches
     return if direct_visibility?
 
-    account&.increment_count!(:statuses_count)
+    account&.increment_count!(:statuses_count, status_created_at: created_at)
     reblog&.increment_count!(:reblogs_count) if reblog?
     thread&.increment_count!(:replies_count) if in_reply_to_id.present? && distributable?
   end

spec/models/concerns/account/counters_spec.rb

@@ -21,6 +21,28 @@ RSpec.describe Account::Counters do
 
       expect(account.statuses_count).to eq increment_by
     end
+
+    it 'updates last_status_at when discovering a new post' do
+      status_created_at = Time.now.utc
+
+      expect { account.increment_count!(:statuses_count, status_created_at:) }
+        .to(change { account.reload.last_status_at })
+    end
+
+    it 'does not update last_status_at when discovering an older post' do
+      account_stat = Fabricate(
+        :account_stat,
+        account: account,
+        last_status_at: 1.day.ago.utc,
+        statuses_count: 10
+      )
+
+      status_created_at = 2.days.ago.utc
+
+      expect { account.increment_count!(:statuses_count, status_created_at:) }
+        .to change { account_stat.reload.statuses_count }
+        .and(not_change { account_stat.reload.last_status_at })
+    end
   end
 
   describe '#decrement_count!' do