ros2 config_error ai_generated true

[WARN] [parameter_handler]: Parameter 'my_param' not found in node, override ignored

ID: ros2/parameter-override-not-applied

Also available as: JSON · Markdown · 中文
90%Fix Rate
86%Confidence
1Evidence
2024-02-14First Seen

Version Compatibility

VersionStatusIntroducedDeprecatedNotes
ROS2 Humble active — — —
ROS2 Iron active — — —
ROS2 Jazzy active — — —

Root Cause

A parameter override (via YAML file, command line, or launch file) specifies a parameter name that the node has not declared using declare_parameter(), so the override is silently dropped.

generic

中文

参数覆盖（通过YAML文件、命令行或启动文件）指定了一个节点未使用declare_parameter()声明的参数名，因此覆盖被静默丢弃。

Official Documentation

https://docs.ros.org/en/humble/Tutorials/Intermediate/Parameters/Understanding-ROS2-Parameters.html

Workarounds

  1. 95% success Add a declare_parameter() call in the node's constructor for the missing parameter: 'this->declare_parameter<std::string>('my_param', 'default_value');'. Then rebuild and rerun. 
    Add a declare_parameter() call in the node's constructor for the missing parameter: 'this->declare_parameter<std::string>('my_param', 'default_value');'. Then rebuild and rerun.
  2. 90% success Check the exact parameter name by running 'ros2 param list /node_name' after starting the node to see which parameters are declared, and adjust the override file accordingly. 
    Check the exact parameter name by running 'ros2 param list /node_name' after starting the node to see which parameters are declared, and adjust the override file accordingly.
  3. 85% success If using a launch file, ensure the parameter is passed with the correct namespace: e.g., for node 'my_node', use '/my_node/my_param' in the YAML file. 
    If using a launch file, ensure the parameter is passed with the correct namespace: e.g., for node 'my_node', use '/my_node/my_param' in the YAML file.

中文步骤

  1. 在节点的构造函数中添加declare_parameter()调用以声明缺失的参数：'this->declare_parameter<std::string>('my_param', 'default_value');'。然后重新构建并运行。
  2. 通过启动节点后运行'ros2 param list /node_name'检查确切的参数名，并相应调整覆盖文件。
  3. 如果使用启动文件，确保参数以正确的命名空间传递：例如，对于节点'my_node'，在YAML文件中使用'/my_node/my_param'。

Dead Ends

Common approaches that don't work:

  1. Adding the parameter to the YAML file with a different name hoping it will be automatically matched 90% fail

    The parameter name must exactly match the declared parameter; typos or case mismatches cause the override to be ignored.

  2. Removing all parameter declarations from the node code to avoid the warning 95% fail

    Without declarations, the node cannot use parameters at all; overrides will still be ignored because there is no declared parameter to accept them.