Fix ros2#894

Signed-off-by: Markus Hofstaetter <markus.hofstaetter@ait.ac.at>

rclpy/rclpy/node.py

@@ -453,6 +453,11 @@ def declare_parameters(
             # Get the values from the tuple, checking its types.
             # Use defaults if the tuple doesn't contain value and / or descriptor.
             name = parameter_tuple[0]
+            if namespace:
+                name = f'{namespace}.{name}'
+
+            # Note(jubeira): declare_parameters verifies the name, but set_parameters doesn't.
+            validate_parameter_name(name)
             second_arg = parameter_tuple[1] if 1 < len(parameter_tuple) else None
             descriptor = parameter_tuple[2] if 2 < len(parameter_tuple) else ParameterDescriptor()
 
@@ -503,12 +508,6 @@ def declare_parameters(
             if not ignore_override and name in self._parameter_overrides:
                 value = self._parameter_overrides[name].value
 
-            if namespace:
-                name = f'{namespace}.{name}'
-
-            # Note(jubeira): declare_parameters verifies the name, but set_parameters doesn't.
-            validate_parameter_name(name)
-
             parameter_list.append(Parameter(name, value=value))
             descriptors.update({name: descriptor})