Deprecate the experimental EventsExecutor

[skyegalaxy]

Description

This PR adds a compile-time deprecation warning when using the experimental EventsExecutor, warning to switch to the new Callback Group Events Executor in single-threaded mode instead.

Tests which exercise the EventsExecutor have deprecation warnings disabled while it is still in the source tree.
Also replaces one usage of the old executor with the new one in rclcpp_action/test_server.cpp.

Fixes # (issue)

Is this user-facing behavior change?

Users will now get a compiler warning when using the experimental EventsExecutor in their application code

Did you use Generative AI?

Claude Opus 4.8 was used to identify spots in the codebase where the deprecation warning suppression should be introduced.

Additional Information

This ought to be backported to at least Lyrical

[mergify]

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[ahcorde]

Pulls: #3192
Gist: https://gist.githubusercontent.com/ahcorde/1a920ab6b77eb06bacef590a582b7738/raw/9ce7ddf78505ff1ed14376ae22de2afa6bd97923/ros2.repos
BUILD args: --packages-above-and-dependencies rclcpp rclcpp_action
TEST args: --packages-above rclcpp rclcpp_action
ROS Distro: rolling
Job: ci_launcher
ci_launcher ran: https://ci.ros2.org/job/ci_launcher/19837

• Linux
• Linux-aarch64
• Linux-rhel
• Windows

[ahcorde]

I can see one warning https://ci.ros2.org/job/ci_linux-aarch64/22485/clang-tidy/

[skyegalaxy]

I can see one warning https://ci.ros2.org/job/ci_linux-aarch64/22485/clang-tidy/

fixed in 3cb984c

[skyegalaxy]

• Linux
• Linux-aarch64
• Linux-rhel
• Windows

[fujitatomoya]

lgtm with green CI

[jmachowinski]

Pulls: #3192
Gist: https://gist.githubusercontent.com/jmachowinski/f03f0e83fe0a7cd86f05ef9ecfdbafd7/raw/9ce7ddf78505ff1ed14376ae22de2afa6bd97923/ros2.repos
BUILD args:
TEST args:
ROS Distro: rolling
Job: ci_launcher
ci_launcher ran: https://ci.ros2.org/job/ci_launcher/19864

• Linux
• Linux-aarch64
• Linux-rhel
• Windows

[skyegalaxy]

• Linux
• Linux-aarch64
• Linux-rhel
• Windows

[skyegalaxy]

@jmachowinski - I think the hanging rclcpp_action/test_server case actually exposes a polymorphism issue with the EventsCBGExecutor. Calling spin_until_future_complete on an EventsCBGExecutor passed in a function as an rclcpp::Executor means that the cbg executor's own spin_until_future_complete is not exercised. Executor::spin_until_future_complete_impl calls spin_once_impl, which the EventsExecutor actually overrides (it leans on more common executor code) but the EventsCBGExecutor does not, resulting in the base class version being called instead (erroneously using the waitsets).

I can get the test to pass by changing the hanging send_goal_request to use a templated arg for the executor so the proper spin_until_future_complete is called, but that feels like a workaround. Perhaps before merging this PR we ought to look into some of the code cleanup / more use of common executor code paths we've been talking about in some of the other PRs, or just have that test continue to use the EventsExecutor and change it in a future PR once we have a proper fix

[ahcorde]

• Linux-aarch64

[skyegalaxy]

https://github.com/Mergifyio backport lyrical

[mergify]

backport lyrical

✅ Backports have been created

Details

• #3206 Deprecate the experimental EventsExecutor (backport #3192) has been created for branch lyrical but encountered conflicts

Cherry-pick of 5272750 has failed:

On branch mergify/bp/lyrical/pr-3192
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Changes to be committed:
	modified:   rclcpp/include/rclcpp/experimental/executors/events_executor/events_executor.hpp
	modified:   rclcpp/src/rclcpp/experimental/executors/events_executor/events_executor.cpp
	modified:   rclcpp/test/rclcpp/executors/executor_types.hpp
	modified:   rclcpp/test/rclcpp/executors/test_executors_warmup.cpp
	modified:   rclcpp_action/test/test_server.cpp
	modified:   rclcpp_components/src/component_container_event.cpp

Unmerged paths:
  (use "git add <file>..." to mark resolution)
	both modified:   rclcpp/test/rclcpp/executors/test_events_executor.cpp

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