Add a deserialize method to Subscription

[StefanFabian]

This enables users to use a SerializedMessage callback and deserialize later.

Not ABI breaking, so can be backported.

My use case is bandwidth monitoring, so I know the size of the message that was transmitted and can add monitoring to qml6_ros2_plugin and rqml.

[Copilot]

Pull request overview

Adds an API on BabelFishSubscription to deserialize an rclcpp::SerializedMessage into a CompoundMessage, enabling deferred decoding of serialized subscription data.

Changes:

• Introduce BabelFishSubscription::deserialize(const rclcpp::SerializedMessage&, CompoundMessage&).
• Implement deserialization using rclcpp::SerializationBase and the subscription’s type support.
• Add a gtest validating round-trip behavior for serialized subscription callbacks.

Reviewed changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated 2 comments.

File	Description
ros_babel_fish/test/message_decoding.cpp	Adds a new test that receives a SerializedMessage and verifies subscription->deserialize(...) produces the expected CompoundMessage.
ros_babel_fish/src/detail/babel_fish_subscription.cpp	Implements deserialize(...) using ROS 2 serialization utilities.
ros_babel_fish/include/ros_babel_fish/detail/babel_fish_subscription.hpp	Declares the new deserialize(...) method on BabelFishSubscription.

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[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
1 Accepted issue

Measures
0 Security Hotspots
No data about Coverage
0.0% Duplication on New Code

See analysis details on SonarQube Cloud

[StefanFabian]

Backport failed for humble, because it was unable to cherry-pick the commit(s).

Please cherry-pick the changes locally and resolve any conflicts.

git fetch origin humble
git worktree add -d .worktree/backport-19-to-humble origin/humble
cd .worktree/backport-19-to-humble
git switch --create backport-19-to-humble
git cherry-pick -x 8fbbefc47ea389c7a5c7fbd0b2f7759d19bd65bf

[StefanFabian]

Successfully created backport PR for jazzy:

• [Backport jazzy] Add a deserialize method to Subscription #20

[StefanFabian]

Successfully created backport PR for kilted:

• [Backport kilted] Add a deserialize method to Subscription #21