Allow passing logger by const ref (#820)

Signed-off-by: Karsten Knese <karsten@openrobotics.org>

rclcpp/resource/logging.hpp.em

@@ -95,7 +95,7 @@ def is_supported_feature_combination(feature_combination):
 #define RCLCPP_@(severity)@(suffix)(logger, @(''.join([p + ', ' for p in get_macro_parameters(feature_combination).keys()]))...) \
   do { \
     static_assert( \
-      ::std::is_same<typename std::remove_reference<typename std::remove_cv<decltype(logger)>::type>::type, \
+      ::std::is_same<typename std::remove_cv<typename std::remove_reference<decltype(logger)>::type>::type, \
       typename ::rclcpp::Logger>::value, \
       "First argument to logging macros must be an rclcpp::Logger"); \
     RCUTILS_LOG_@(severity)@(suffix)_NAMED( \

rclcpp/test/test_logging.cpp

@@ -162,3 +162,28 @@ TEST_F(TestLoggingMacros, test_logging_skipfirst) {
     EXPECT_EQ(i - 1, g_log_calls);
   }
 }
+
+bool log_function(rclcpp::Logger logger)
+{
+  RCLCPP_INFO(logger, "successful log");
+  return true;
+}
+
+bool log_function_const(const rclcpp::Logger logger)
+{
+  RCLCPP_INFO(logger, "successful log");
+  return true;
+}
+
+bool log_function_const_ref(const rclcpp::Logger & logger)
+{
+  RCLCPP_INFO(logger, "successful log");
+  return true;
+}
+
+TEST_F(TestLoggingMacros, test_log_from_node) {
+  auto logger = rclcpp::get_logger("test_logging_logger");
+  EXPECT_TRUE(log_function(logger));
+  EXPECT_TRUE(log_function_const(logger));
+  EXPECT_TRUE(log_function_const_ref(logger));
+}