set QoS History KEEP_ALL explicitly for statistics publisher. (#2650)

* set QoS History KEEP_ALL explicitly for statistics publisher.

Signed-off-by: Tomoya Fujita <[email protected]>

* test_subscription_options adjustment.

Signed-off-by: Tomoya Fujita <[email protected]>

---------

Signed-off-by: Tomoya Fujita <[email protected]>

Author: fujitatomoya

rclcpp/include/rclcpp/subscription_options.hpp

@@ -80,7 +80,8 @@ struct SubscriptionOptionsBase
 
     // An optional QoS which can provide topic_statistics with a stable QoS separate from
     // the subscription's current QoS settings which could be unstable.
-    rclcpp::QoS qos = SystemDefaultsQoS();
+    // Explicitly set the enough depth to avoid missing the statistics messages.
+    rclcpp::QoS qos = SystemDefaultsQoS().keep_last(10);
   };
 
   TopicStatisticsOptions topic_stats_options;

rclcpp/test/rclcpp/test_subscription_options.cpp

@@ -65,7 +65,7 @@ TEST_F(TestSubscriptionOptions, topic_statistics_options_default_and_set) {
   EXPECT_EQ(options.topic_stats_options.state, rclcpp::TopicStatisticsState::NodeDefault);
   EXPECT_EQ(options.topic_stats_options.publish_topic, defaultPublishTopic);
   EXPECT_EQ(options.topic_stats_options.publish_period, 1s);
-  EXPECT_EQ(options.topic_stats_options.qos, rclcpp::SystemDefaultsQoS());
+  EXPECT_EQ(options.topic_stats_options.qos, rclcpp::SystemDefaultsQoS().keep_last(10));
 
   options.topic_stats_options.state = rclcpp::TopicStatisticsState::Enable;
   options.topic_stats_options.publish_topic = "topic_statistics";