Reject invalid executable boolean attributes

launch/launch/actions/execute_process.py

@@ -198,7 +198,8 @@ def __init__(
         :param: additional_env dictionary of environment variables to be added.
             If 'env' was None, they are added to the current environment.
             If not, 'env' is updated with additional_env.
-        :param: shell if True, a shell is used to execute the cmd
+        :param: shell if True, a shell is used to execute the cmd. This must be
+            a boolean value in XML launch files; substitutions are not supported.
         :param: sigterm_timeout time until shutdown should escalate to SIGTERM,
             as a string or a list of strings and Substitutions to be resolved
             at runtime, defaults to the LaunchConfiguration called
@@ -211,6 +212,8 @@ def __init__(
             be overridden with the LaunchConfiguration called 'emulate_tty',
             the value of which is evaluated as true or false according to
             :py:func:`evaluate_condition_expression`.
+            In XML launch files, this attribute must be a boolean value;
+            substitutions are not supported.
             Throws :py:exc:`InvalidConditionExpressionError` if the
             'emulate_tty' configuration does not represent a boolean.
         :param: prefix a set of commands/arguments to precede the cmd, used for
@@ -411,12 +414,13 @@ def parse(
                 kwargs['sigterm_timeout'] = str(sigterm_timeout)
 
         if 'shell' not in ignore:
-            shell = entity.get_attr('shell', data_type=bool, optional=True)
+            shell = entity.get_attr('shell', data_type=bool, optional=True, can_be_str=False)
             if shell is not None:
                 kwargs['shell'] = shell
 
         if 'emulate_tty' not in ignore:
-            emulate_tty = entity.get_attr('emulate_tty', data_type=bool, optional=True)
+            emulate_tty = entity.get_attr(
+                'emulate_tty', data_type=bool, optional=True, can_be_str=False)
             if emulate_tty is not None:
                 kwargs['emulate_tty'] = emulate_tty
 

launch_xml/test/launch_xml/test_executable.py

@@ -69,6 +69,35 @@ def test_executable_wrong_subtag():
     assert 'whats_this' in str(excinfo.value)
 
 
+@pytest.mark.parametrize(
+    'value', ['true', 'false', 'True', 'False', 'yes', 'no', 'on', 'off', '1', '0'])
+@pytest.mark.parametrize('attribute', ['shell', 'emulate_tty'])
+def test_executable_accepts_boolean_values(attribute, value):
+    """Accept the boolean spellings supported by the XML type converter."""
+    xml_file = textwrap.dedent(f"""
+        <launch>
+            <executable cmd="echo test" {attribute}="{value}" />
+        </launch>
+    """)
+    root_entity, parser = load_no_extensions(io.StringIO(xml_file))
+    executable = parser.parse_description(root_entity).entities[0]
+    assert getattr(executable, attribute) is (value.lower() in ('true', 'yes', 'on', '1'))
+
+
+@pytest.mark.parametrize('attribute', ['shell', 'emulate_tty'])
+def test_executable_rejects_arbitrary_boolean_strings(attribute):
+    """Reject arbitrary strings for boolean executable attributes."""
+    for value in ('', ' ', 'not-a-boolean', '$(var flag)'):
+        xml_file = textwrap.dedent(f"""
+            <launch>
+                <executable cmd="echo test" {attribute}="{value}" />
+            </launch>
+        """)
+        root_entity, parser = load_no_extensions(io.StringIO(xml_file))
+        with pytest.raises(TypeError, match=attribute):
+            parser.parse_description(root_entity)
+
+
 def test_executable_on_exit():
     xml_file = \
         """\