handle invalid conversion of non-arithmetic types via custom exception

Author: christianrauch

src/CameraNode.cpp

@@ -459,8 +459,16 @@ CameraNode::declareParameters()
       throw std::runtime_error("minimum and maximum parameter array sizes do not match");
 
     // clamp default ControlValue to min/max range and cast ParameterValue
-    const rclcpp::ParameterValue value =
-      cv_to_pv(clamp(info.def(), info.min(), info.max()));
+    rclcpp::ParameterValue value;
+    try {
+      value = cv_to_pv(clamp(info.def(), info.min(), info.max()));
+    }
+    catch (const invalid_conversion &e) {
+      RCLCPP_ERROR_STREAM(get_logger(), "unsupported control '" << id->name() << "' (type: "
+                                                                << std::to_string(info.def().type())
+                                                                << "): " << e.what());
+      continue;
+    }
 
     // get smallest bounds for minimum and maximum set
     rcl_interfaces::msg::IntegerRange range_int;

src/cv_to_pv.cpp

@@ -48,7 +48,7 @@ template<typename T,
 rclcpp::ParameterValue
 cv_to_pv_array(const std::vector<T> & /*values*/)
 {
-  throw std::runtime_error("ParameterValue only supported for arithmetic types");
+  throw invalid_conversion("ParameterValue only supported for arithmetic types");
 }
 
 template<typename T,

src/cv_to_pv.hpp

@@ -4,6 +4,13 @@
 #include <rclcpp/parameter_value.hpp>
 
 
+class invalid_conversion : public std::runtime_error
+{
+public:
+  explicit invalid_conversion(const std::string &msg) : std::runtime_error(msg) {};
+};
+
+
 rclcpp::ParameterValue
 cv_to_pv(const libcamera::ControlValue &value);