Adding a slot_type message field to python msg classes

rosidl_generator_py/resource/_msg.py.em

@@ -114,9 +114,31 @@ class @(spec.base_type.type)(metaclass=Metaclass):
         '_@(field.name)',
 @[end for]@
     ]
+
+    _slot_types = [
+@[for field in spec.fields]@
+@[  if field.type.is_primitive_type() ]@
+        '@(field.type)',
+@[  else ]@
+@[    if field.type.is_array ]@
+@[      if field.type.array_size ]@
+@[        if field.type.is_upper_bound ]@
+        '@(field.type.pkg_name)/@(field.type.type)[<=@(field.type.array_size)]',
+@[        else ]@
+        '@(field.type.pkg_name)/@(field.type.type)[@(field.type.array_size)]',
+@[        end if ]@
+@[      else ]@
+        '@(field.type.pkg_name)/@(field.type.type)[]',
+@[      end if ]@
+@[    else ]@
+        '@(field.type.pkg_name)/@(field.type.type)',
+@[    end if ]@
+@[  end if ]@
+@[end for]@
+    ]
+
 @
 @[if len(spec.fields) > 0]@
-
     def __init__(self, **kwargs):
         assert all('_' + key in self.__slots__ for key in kwargs.keys()), \
             'Invalid arguments passed to constructor: %s' % \

rosidl_generator_py/test/test_interfaces.py

@@ -257,3 +257,45 @@ def test_out_of_range():
         setattr(b, 'unbounded_uint64_values', [2**64])
     with pytest.raises(AssertionError):
         setattr(b, 'unbounded_uint64_values', [-1])
+
+
+def test_slot_attributes():
+    a = Nested()
+    assert hasattr(a, '_slot_types')
+    assert hasattr(a, '__slots__')
+    nested_slot_types = getattr(a, '_slot_types')
+    nested_slots = getattr(a, '__slots__')
+    assert len(nested_slot_types) == len(nested_slots)
+    expected_nested_slot_types = [
+        'rosidl_generator_py/Primitives',
+        'rosidl_generator_py/Primitives[2]',
+        'rosidl_generator_py/Primitives[<=3]',
+        'rosidl_generator_py/Primitives[]',
+    ]
+    assert len(nested_slot_types) == len(expected_nested_slot_types)
+
+    for i, expected_nested_slot_type in enumerate(expected_nested_slot_types):
+        assert nested_slot_types[i] == expected_nested_slot_type
+
+    b = StringArrays()
+    assert hasattr(b, '_slot_types')
+    assert hasattr(b, '__slots__')
+    string_slot_types = getattr(b, '_slot_types')
+    string_slots = getattr(b, '__slots__')
+    assert len(string_slot_types) == len(string_slots)
+    expected_string_slot_types = [
+        'string<=5[3]',
+        'string<=5[<=10]',
+        'string<=5[]',
+        'string[]',
+        'string[3]',
+        'string[<=10]',
+        'string[]',
+        'string[3]',
+        'string[<=10]',
+        'string[]',
+        'string[]',
+    ]
+    assert len(string_slot_types) == len(expected_string_slot_types)
+    for i, slot_type in enumerate(expected_string_slot_types):
+        assert string_slot_types[i] == slot_type