rcl_jump_threshold does not disable forward jump

[Kettenhoax]

Bug report

Required Info:

• Operating System:
  • Ubuntu 20.04
• Installation type:
  • rolling binaries
• Version or commit hash:
  • ros-rolling-rcl 4.0.0-1focal.20210921.175344
• DDS implementation:
  • CycloneDDS
• Client library (if applicable):
  • rclcpp

Steps to reproduce issue

Define a clock jump handler for your node, and set the forward threshold to 0, which according to rcl/time.h should disable forward jumps.

#include <functional>
#include "rclcpp/rclcpp.hpp"

class TestNode : public rclcpp::Node
{
private:
  rclcpp::JumpHandler::SharedPtr jump_handler_;

public:
  TestNode() : Node("test")
  {
    rcl_jump_threshold_t jump_threshold;
    jump_threshold.on_clock_change = true;
    jump_threshold.min_forward.nanoseconds = 0;
    jump_threshold.min_backward.nanoseconds = -1;
    jump_handler_ =
      get_clock()->create_jump_callback(
      nullptr,
      std::bind(&TestNode::onJump, this, std::placeholders::_1), jump_threshold);
  }

private:
  void onJump(const rcl_time_jump_t & jump)
  {
    RCLCPP_INFO(this->get_logger(), "Jump of '%li'", jump.delta.nanoseconds);
  }
};

int main(int argc, char * argv[])
{
  rclcpp::init(argc, argv);
  rclcpp::spin(std::make_shared<TestNode>());
  rclcpp::shutdown();
  return 0;
}

Compile and run with sim time

./jump --ros-args -p use_sim_time:=true

Simultaneously publish /clock messages:

import rclpy
from rclpy.qos import qos_profile_sensor_data
from rclpy.node import Node
from rosgraph_msgs.msg import Clock

class PublishClock(Node):
    def __init__(self):
        super().__init__('publish_clock')
        self._pub = self.create_publisher(Clock, 'clock', qos_profile_sensor_data)
        self._timer = self.create_timer(1.0, self._on_timer)

    def _on_timer(self):
        msg = Clock()
        msg.clock = self.get_clock().now().to_msg()
        self._pub.publish(msg)

rclpy.init()
rclpy.spin(PublishClock())

Expected behavior

The callback is never called and there's no output.

Actual behavior

Output is written at every received /clock message.

Additional Information

Works as expected without sim time

[sloretz]

I just ran into this too while looking at ros2/rclcpp#1814 :)

I think these checks

rcl/rcl/src/rcl/time.c

Lines 276 to 282 in d8817fd

	if (
	(is_clock_change && info->threshold.on_clock_change) ||
	(time_jump->delta.nanoseconds < 0 &&
	time_jump->delta.nanoseconds <= info->threshold.min_backward.nanoseconds) ||
	(time_jump->delta.nanoseconds > 0 &&
	time_jump->delta.nanoseconds >= info->threshold.min_forward.nanoseconds))
	{

Are supposed to be

    if (
      (is_clock_change && info->threshold.on_clock_change) ||
      (info->threshold.min_backward.nanoseconds < 0 &&
      time_jump->delta.nanoseconds <= info->threshold.min_backward.nanoseconds) ||
      (info->threshold.min_forward.nanoseconds > 0 &&
      time_jump->delta.nanoseconds >= info->threshold.min_forward.nanoseconds))
    {