set_parameters callback returns None

[belalhmedan90]

The callback returns None, and I get an error:

AttributeError: 'NoneType' object has no attribute 'successful'

in this line 832

[fujitatomoya]

can you provide more description about this?

• what is the expected behavior?
• what is the actual behavior?
• self-contained, complete reproducible procedure or sample code.

[bhomaidan1990]

• what is the expected behavior?

To set parameters from a list without Errors.

*what is the actual behavior?

I get the error mentioned above when processing the second parameter

sample code.

from rclpy.node import Node

class Test(Node):
    def __init__(self):
        super.__init__(node_name="test")
        params_list = [
            ("param1", "val1"),
            ("param2", "val2"),
            ("param3", "val3")
        ]
        self.declare_parameters(namespace="package_name", parameters=params_list)

Same Issue happens on Jazzy as well, however different line number:

Full Error msg:

Traceback (most recent call last):
  File "/opt/ros/jazzy/lib/my_pkg/action_server.py", line 441, in <module>
    main()
  File "/opt/ros/jazzy/lib/my_pkg/action_server.py", line 430, in main
    test = Test()
                      ^^^^^^^^^^^^^^^^^^^^^^^
  File "/opt/ros/jazzy/lib/my_pkg/action_server.py", line 79, in __init__
    self.declare_params()
  File "/opt/ros/jazzy/lib/my_pkg/action_server.py", line 166, in declare_params
    self.declare_parameters(namespace="my_pkg", parameters=params_list)
  File "/opt/ros/jazzy/lib/python3.12/site-packages/rclpy/node.py", line 528, in declare_parameters
    self._declare_parameter_common(
  File "/opt/ros/jazzy/lib/python3.12/site-packages/rclpy/node.py", line 577, in _declare_parameter_common
    result = self._set_parameters_atomically_common(
             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/opt/ros/jazzy/lib/python3.12/site-packages/rclpy/node.py", line 910, in _set_parameters_atomically_common
    if not result.successful:
           ^^^^^^^^^^^^^^^^^
AttributeError: 'NoneType' object has no attribute 'successful'
[ros2run]: Process exited with failure 1

[belalhmedan90]

@fujitatomoya if the result of this callback is None, there should be an exception handling, or something like that imo.