rails · curi · May 15, 2026
diff --git a/activerecord/test/cases/test_case.rb b/activerecord/test/cases/test_case.rb
@@ -60,15 +60,18 @@ def check_connection_leaks
           end
         end
 
-        pool.reap
-        pool.connections.each do |conn|
-          if conn.in_use?
-            if conn.owner != Fiber.current && conn.owner != Thread.current
-              leaked_conn << [conn.owner, conn.owner.backtrace]
-              conn.owner&.kill
+        # Avoid racing the pool reaper while it is performing maintenance.
+        pool.reaper_lock do
+          pool.reap
+          pool.connections.each do |conn|
+            if conn.in_use?
+              if conn.owner != Fiber.current && conn.owner != Thread.current
+                leaked_conn << [conn.owner, conn.owner.backtrace]
+                conn.owner&.kill
+              end
+              conn.steal!
+              pool.checkin(conn)
             end
-            conn.steal!
-            pool.checkin(conn)
           end
         end
       end

diff --git a/activerecord/test/cases/test_case_test.rb b/activerecord/test/cases/test_case_test.rb
@@ -0,0 +1,50 @@
+# frozen_string_literal: true
+
+require "cases/helper"
+
+module ActiveRecord
+  class TestCaseLeakCheckTest < ActiveRecord::TestCase
+    include WaitForTestHelper
+
+    self.use_transactional_tests = false
+
+    def test_check_connection_leaks_does_not_report_connections_held_for_reaper_maintenance
+      pool = ActiveRecord::Base.connection_pool
+
+      conn = ActiveRecord::Base.lease_connection
+      conn.select_value("SELECT 1")
+      ActiveRecord::Base.connection_handler.clear_active_connections!
+
+      assert_not_nil conn
+
+      maintenance_started = Concurrent::Event.new
+
+      maintenance_thread = Thread.new do
+        Thread.current.name = "AR Pool Reaper"
+
+        pool.reaper_lock do
+          pool.send(:checkout_for_maintenance, conn)
+          maintenance_started.set
+          sleep 0.2
+          pool.send(:return_from_maintenance, conn)
+        end
+      end
+
+      assert maintenance_started.wait(1), "maintenance thread did not start"
+      wait_for(message: "connection was not checked out for maintenance") do
+        conn.in_use? && conn.owner != ActiveSupport::IsolatedExecutionState.context
+      end
+
+      assert_nothing_raised do
+        check_connection_leaks
+      end
+    ensure
+      maintenance_thread&.join
+
+      if conn&.in_use?
+        conn.steal!
+        pool.checkin(conn)
+      end
+    end
+  end
+end