You're reading the documentation for a development version. For the latest released version, please have a look at Kilted.

Migration Guides: Kilted Kaiju to Lyrical Luth

This list summarizes important changes between Kilted Kaiju (previous) and Lyrical Luth (current) releases, where changes to user code might be necessary.

controller_interface

controller_manager

hardware_interface

The signature for the on_init method in all hardware_interface::*Interface classes has changed (#2323, #2589) from
```
CallbackReturn on_init(const hardware_interface::HardwareInfo& info)
```
to
```
CallbackReturn on_init(const HardwareComponentInterfaceParams& params)
```
The HardwareInfo object can be accessed from the HardwareComponentInterfaceParams object using params.hardware_info. See Writing a Hardware Component for advanced usage of the HardwareComponentInterfaceParams object.

The signature for the init() method in all hardware_interface::*Interface classes has changed (#2344, #2589) from

CallbackReturn init(const HardwareInfo & hardware_info, rclcpp::Logger logger, rclcpp::Clock::SharedPtr clock)

to

CallbackReturn init(const hardware_interface::HardwareComponentParams & params)

The initialize methods of all hardware components (such as Actuator, Sensor, etc.) have been changed from passing a const HardwareInfo & to passing a const HardwareComponentParams & (#2323, #2589).
The get_value of LoanedStateInterface and LoanedCommandInterface is now accessed using get_optional method. The value will be returned as an std::optional<T>. (#2061).

This change was made to better handle cases where the interface value may not be accessible due to a concurrent access from other threads in the system.
The double get_value() of standard StateInterface and CommandInterface is now accessed using get_optional or bool get_value(T & value, bool wait_for_lock) method. The value will be returned as an std::optional<T> when using get_optional (#2831).

Likewise, the set_value method has been updated to bool set_value(const T & value, bool wait_for_lock) and return value is to indicate success or failure of the operation (#2831).

You can use the return values of these methods to handle cases where the interface value may not be accessible due to a concurrent access from other threads in the system. You can set the wait_for_lock parameter to true to block until the lock is acquired, however, this is not real-time safe and should be used with caution in real-time contexts.