Add default constructor to NodeInterfaces (#2094)

* Add default constructor to NodeInterfaces

Signed-off-by: Shane Loretz <[email protected]>

* Remove unnecessary NOLINT

Signed-off-by: Shane Loretz <[email protected]>

---------

Signed-off-by: Shane Loretz <[email protected]>
Signed-off-by: Shane Loretz <[email protected]>

Author: sloretz

rclcpp/include/rclcpp/node_interfaces/detail/node_interfaces_helpers.hpp

@@ -44,6 +44,10 @@ struct NodeInterfacesStorage
   : interfaces_(init_tuple<decltype(node), InterfaceTs ...>(node))
   {}
 
+  NodeInterfacesStorage()
+  : interfaces_()
+  {}
+
   explicit NodeInterfacesStorage(std::shared_ptr<InterfaceTs>... args)
   : interfaces_(args ...)
   {}

rclcpp/include/rclcpp/node_interfaces/node_interfaces.hpp

@@ -147,6 +147,11 @@ class NodeInterfaces
   : NodeInterfacesSupportsT(node)
   {}
 
+  // Create a NodeInterfaces object with no bound interfaces
+  NodeInterfaces()
+  : NodeInterfacesSupportsT()
+  {}
+
   explicit NodeInterfaces(std::shared_ptr<InterfaceTs>... args)
   : NodeInterfacesSupportsT(args ...)
   {}

rclcpp/test/rclcpp/node_interfaces/test_node_interfaces.cpp

@@ -33,6 +33,15 @@ class TestNodeInterfaces : public ::testing::Test
   }
 };
 
+TEST_F(TestNodeInterfaces, default_constructor) {
+  auto node = std::make_shared<rclcpp::Node>("my_node");
+  using rclcpp::node_interfaces::NodeInterfaces;
+  using rclcpp::node_interfaces::NodeBaseInterface;
+  using rclcpp::node_interfaces::NodeGraphInterface;
+  NodeInterfaces<NodeBaseInterface, NodeGraphInterface> interfaces;
+  interfaces = NodeInterfaces<NodeBaseInterface, NodeGraphInterface>(*node);
+}
+
 /*
    Testing NodeInterfaces construction from nodes.
  */