Preserve iterable executable arguments

launch/launch/descriptions/executable.py

@@ -18,6 +18,7 @@
 """Module for a description of an Executable."""
 
 import os
+import pathlib
 import re
 import shlex
 import threading
@@ -74,9 +75,13 @@ def __init__(
             additional_env.
         :param arguments: list of extra arguments for the executable
         """
+        self.__arguments = None if arguments is None else [
+            argument if isinstance(argument, (str, pathlib.Path, Substitution)) else list(argument)
+            for argument in arguments
+        ]
         self.__cmd = [normalize_to_list_of_substitutions(x) for x in cmd]
-        self.__cmd += ([] if arguments is None
-                       else [normalize_to_list_of_substitutions(x) for x in arguments])
+        self.__cmd += ([] if self.__arguments is None
+                       else [normalize_to_list_of_substitutions(x) for x in self.__arguments])
         self.__prefix = normalize_to_list_of_substitutions(
             LaunchConfiguration('launch-prefix', default='') if prefix is None else prefix
         )
@@ -99,7 +104,6 @@ def __init__(
                 self.__additional_env.append((
                     normalize_to_list_of_substitutions(key),
                     normalize_to_list_of_substitutions(value)))
-        self.__arguments = arguments
         self.__final_cmd: Optional[List[str]] = None
         self.__final_cwd: Optional[str] = None
         self.__final_env: Optional[Dict[str, str]] = None

launch/test/launch/test_executable.py

@@ -45,6 +45,22 @@ def test_cmd_multiple_arguments_in_string():
     assert all(a == b for a, b in zip(exe.final_cmd, ['ls', '-opt1', '-opt2', '-opt3']))
 
 
+def test_arguments_generator_is_preserved():
+    arguments = (value for value in ['--flag', 'value'])
+    exe = Executable(cmd=['test'], arguments=arguments)
+    exe.prepare(LaunchContext(), None)
+    assert exe.final_cmd == ['test', '--flag', 'value']
+    assert list(exe.arguments) == ['--flag', 'value']
+
+
+def test_nested_argument_generator_is_preserved():
+    argument = (value for value in ['--', 'flag'])
+    exe = Executable(cmd=['test'], arguments=[argument])
+    exe.prepare(LaunchContext(), None)
+    assert exe.final_cmd == ['test', '--flag']
+    assert exe.arguments == [['--', 'flag']]
+
+
 def test_passthrough_properties():
     name = 'name'
     cwd = 'cwd'