From 28d7910faa9ee192d2c3744638fd76b63d9f2355 Mon Sep 17 00:00:00 2001
From: Jesus Armando Anaya <armando@robomous.ai>
Date: Thu, 9 Apr 2026 11:08:13 -0700
Subject: [PATCH] fix(BuildTools): forward --ros2 and --dds-middleware to UE4
 editor command line

Fixes #9511
---
 Util/BuildTools/BuildCarlaUE4.bat |  5 +++++
 Util/BuildTools/BuildCarlaUE4.sh  | 16 +++++++++++++++-
 2 files changed, 20 insertions(+), 1 deletion(-)

diff --git a/Util/BuildTools/BuildCarlaUE4.bat b/Util/BuildTools/BuildCarlaUE4.bat
index 2c6e70149b7..075e64798c7 100644
--- a/Util/BuildTools/BuildCarlaUE4.bat
+++ b/Util/BuildTools/BuildCarlaUE4.bat
@@ -75,6 +75,11 @@ if not "%1"=="" (
 rem remove quotes from arguments
 set EDITOR_FLAGS=%EDITOR_FLAGS:"=%
 
+rem Forward ROS2 runtime flags to the UE4 editor command line
+if %USE_ROS2% == true (
+    set EDITOR_FLAGS=%EDITOR_FLAGS% --ros2
+)
+
 if %REMOVE_INTERMEDIATE% == false (
     if %LAUNCH_UE4_EDITOR% == false (
         if %BUILD_UE4_EDITOR% == false (
diff --git a/Util/BuildTools/BuildCarlaUE4.sh b/Util/BuildTools/BuildCarlaUE4.sh
index b67dd56292c..55dc0e48a0f 100755
--- a/Util/BuildTools/BuildCarlaUE4.sh
+++ b/Util/BuildTools/BuildCarlaUE4.sh
@@ -19,13 +19,14 @@ USE_PYTORCH=false
 USE_UNITY=true
 USE_ROS2=false
 CHRONO_PATH=""
+DDS_MIDDLEWARE=""
 
 EDITOR_FLAGS=""
 
 GDB=
 RHI="-vulkan"
 
-OPTS=`getopt -o h --long help,build,rebuild,launch,clean,hard-clean,gdb,opengl,carsim,pytorch,chrono,chrono-path:,ros2,no-simready,no-unity,editor-flags: -n 'parse-options' -- "$@"`
+OPTS=`getopt -o h --long help,build,rebuild,launch,clean,hard-clean,gdb,opengl,carsim,pytorch,chrono,chrono-path:,ros2,dds-middleware:,no-simready,no-unity,editor-flags: -n 'parse-options' -- "$@"`
 
 eval set -- "$OPTS"
 
@@ -73,6 +74,9 @@ while [[ $# -gt 0 ]]; do
     --ros2 )
       USE_ROS2=true;
       shift ;;
+    --dds-middleware )
+      DDS_MIDDLEWARE=$2;
+      shift 2 ;;
     --no-simready )
       USE_SIMREADY=false
       shift ;;
@@ -89,6 +93,16 @@ while [[ $# -gt 0 ]]; do
   esac
 done
 
+# Forward ROS2 runtime flags to the UE4 editor command line.
+# --ros2 is consumed above for build-time config (OptionalModules.ini);
+# the editor also needs it as a runtime flag for CarlaSettings.
+if ${USE_ROS2} ; then
+  EDITOR_FLAGS="${EDITOR_FLAGS} --ros2"
+fi
+if [ -n "${DDS_MIDDLEWARE}" ] ; then
+  EDITOR_FLAGS="${EDITOR_FLAGS} --dds-middleware=${DDS_MIDDLEWARE}"
+fi
+
 # ==============================================================================
 # -- Set up environment --------------------------------------------------------
 # ==============================================================================