ParameterUninitializedException on accessing parameter that is not ye…

…t set crashes node

  ros2/rclpy#1030

Signed-off-by: Tomoya Fujita <[email protected]>

prover_rclpy/setup.py

@@ -60,6 +60,7 @@
             'rclpy_foo_940 = src.rclpy_foo_940:main',
             'rclpy_bar_940 = src.rclpy_bar_940:main',
             'ros2_1173 = src.ros2_1173:main',
+            'rclpy_1030 = src.rclpy_1030:main',
         ],
     },
 )

prover_rclpy/src/rclpy_1030.py

@@ -0,0 +1,28 @@
+import rclpy
+from rclpy.node import Node
+from rclpy.parameter import Parameter
+from rcl_interfaces.msg import SetParametersResult
+
+
+class MinimalParam(Node):
+    def __init__(self):
+        super().__init__('minimal_param_node')
+        self.log = self.get_logger()
+        self.declare_parameter('my_parameter', Parameter.Type.STRING)
+
+        self.add_on_set_parameters_callback(self.callback)
+
+    def callback(self, parameters):
+        for p in parameters:
+            if p.name == 'my_parameter':
+                self.log.info(f"Got my_parameter: {p.value}")
+        return SetParametersResult(successful=True)
+
+
+def main():
+    rclpy.init()
+    node = MinimalParam()
+    rclpy.spin(node)
+
+if __name__ == '__main__':
+    main()