From fc7dec59349acc3e2c8ad7f51795b344ac4e6608 Mon Sep 17 00:00:00 2001
From: Old-Ding <35417409+Old-Ding@users.noreply.github.com>
Date: Sat, 11 Jul 2026 16:19:14 +0800
Subject: [PATCH 1/2] Preserve iterable executable arguments

Materialize extra arguments once so command construction does not exhaust
the iterable exposed by the public arguments property.

Signed-off-by: Old-Ding <35417409+Old-Ding@users.noreply.github.com>
---
 launch/launch/descriptions/executable.py | 6 +++---
 launch/test/launch/test_executable.py    | 8 ++++++++
 2 files changed, 11 insertions(+), 3 deletions(-)

diff --git a/launch/launch/descriptions/executable.py b/launch/launch/descriptions/executable.py
index 73aaeeefc..5b4f666ef 100644
--- a/launch/launch/descriptions/executable.py
+++ b/launch/launch/descriptions/executable.py
@@ -74,9 +74,10 @@ def __init__(
             additional_env.
         :param arguments: list of extra arguments for the executable
         """
+        self.__arguments = None if arguments is None else list(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 +100,6 @@ 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
diff --git a/launch/test/launch/test_executable.py b/launch/test/launch/test_executable.py
index a62d33baf..8747cd9b2 100644
--- a/launch/test/launch/test_executable.py
+++ b/launch/test/launch/test_executable.py
@@ -45,6 +45,14 @@ 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_passthrough_properties():
     name = 'name'
     cwd = 'cwd'

From a9d660c68d5d5d54af48a455495119e16703d80d Mon Sep 17 00:00:00 2001
From: Old-Ding <35417409+Old-Ding@users.noreply.github.com>
Date: Mon, 13 Jul 2026 04:27:38 +0800
Subject: [PATCH 2/2] Preserve nested iterable executable arguments

Materialize each nested argument iterable before command construction so
the public arguments property retains the values consumed by normalization.

Signed-off-by: Old-Ding <35417409+Old-Ding@users.noreply.github.com>
---
 launch/launch/descriptions/executable.py | 6 +++++-
 launch/test/launch/test_executable.py    | 8 ++++++++
 2 files changed, 13 insertions(+), 1 deletion(-)

diff --git a/launch/launch/descriptions/executable.py b/launch/launch/descriptions/executable.py
index 5b4f666ef..eb766f2e0 100644
--- a/launch/launch/descriptions/executable.py
+++ b/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
@@ -74,7 +75,10 @@ def __init__(
             additional_env.
         :param arguments: list of extra arguments for the executable
         """
-        self.__arguments = None if arguments is None else list(arguments)
+        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 self.__arguments is None
                        else [normalize_to_list_of_substitutions(x) for x in self.__arguments])
diff --git a/launch/test/launch/test_executable.py b/launch/test/launch/test_executable.py
index 8747cd9b2..0a9465f8a 100644
--- a/launch/test/launch/test_executable.py
+++ b/launch/test/launch/test_executable.py
@@ -53,6 +53,14 @@ def test_arguments_generator_is_preserved():
     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'