Deprecated subscription callback signatures are still compiling

[mini-1235]

Generated by Generative AI

No

Operating System:

Linux mini1235-XPS-15-9520 6.8.0-86-generic #87-Ubuntu SMP PREEMPT_DYNAMIC Mon Sep 22 18:03:36 UTC 2025 x86_64 x86_64 x86_64 GNU/Linux

ROS version or commit hash:

Rolling

RMW implementation (if applicable):

No response

RMW Configuration (if applicable):

No response

Client library (if applicable):

No response

'ros2 doctor --report' output

ros2 doctor --report

<COPY OUTPUT HERE>

Steps to reproduce issue

1. Create subscription with deprecated syntax

sub_ = this->create_subscription<std_msgs::msg::Int32>(
      input,
      10,
      [](std::shared_ptr<std_msgs::msg::Int32> msg)

Expected behavior

Reports error or warning when compile

Actual behavior

Nothing happen

Additional information

https://docs.ros.org/en/rolling/Releases/Release-Jazzy-Jalisco.html#deprecated-subscription-callback-signatures-were-removed

states that

Back in Humble, subscription signatures of the form void callback(std::shared_ptr<MessageT>) and void callback(std::shared_ptr<MessageT>, const rclcpp::MessageInfo &) were deprecated.

In Jazzy, these subscription signatures have been removed.
Users should switch to using void callback(std::shared_ptr<const MessageT>) or void callback(std::shared_ptr<const MessageT>, const rclcpp MessageInfo &).

Related PRs in this repo are:

• refactor AnySubscriptionCallback and add/deprecate callback signatures #1598
• Deprecate the void shared_ptr<MessageT> subscription callback signatures #1713 - deprecates the syntax
• Remove the set_deprecated signatures in any_subscription_callback. #2431 - removes the deprecation warnings

In the latest version, I am still able to use the syntax std::shared_ptr<MessageT> in the callback, is this intended?
If no, why don't we remove the deprecated signature as well?

rclcpp/rclcpp/include/rclcpp/any_subscription_callback.hpp

Lines 140 to 154 in 4d14414

	// Deprecated signatures:
	using SharedPtrCallback =
	std::function<void (std::shared_ptr<SubscribedType>)>;
	using SharedPtrROSMessageCallback =
	std::function<void (std::shared_ptr<ROSMessageType>)>;
	using SharedPtrWithInfoCallback =
	std::function<void (std::shared_ptr<SubscribedType>, const rclcpp::MessageInfo &)>;
	using SharedPtrWithInfoROSMessageCallback =
	std::function<void (
	std::shared_ptr<ROSMessageType>,
	const rclcpp::MessageInfo &)>;
	using SharedPtrSerializedMessageCallback =
	std::function<void (std::shared_ptr<rclcpp::SerializedMessage>)>;
	using SharedPtrSerializedMessageWithInfoCallback =
	std::function<void (std::shared_ptr<rclcpp::SerializedMessage>, const rclcpp::MessageInfo &)>;

This is something I noticed in ros2/ros2_documentation#2333 (comment), where the ros2/demos#532 changes from const sensor_msgs::msg::Image::SharedPtr to sensor_msgs::msg::Image::ConstSharedPtr and breaks the tutorial

[christophebedard]

🧇 it indeed seems like the deprecations were removed, but that the support for std::shared_ptr<MessageT> (+ info) was mistakenly not removed. We don't see any reason why. A PR to remove them would be appreciated!

[mini-1235]

@christophebedard Thanks for the reply! The deprecation warning was removed in early 2024, and since std::shared_ptr<MessageT> has continued compiling without any warnings for quite a while, many users may not even be aware that it was ever deprecated. Before opening a PR, I would like to double check if it's ok to remove this support now, given that it may impact existing user code. And, the expected behavior after removing this support would be a compile-time error, yes?

[mjcarroll]

At the very least, lets open a PR to remove it and see how CI fares through the core. We can then consider if this is worth landing in rolling (and therefore lyrical), or if we need to re-add a deprecation warning for another cycle.