change how commands are executed

tools/roslaunch/src/roslaunch/loader.py

@@ -38,6 +38,7 @@
 
 import errno
 import os
+import sys
 from copy import deepcopy
 
 import yaml
@@ -491,7 +492,41 @@ def param_value(self, verbose, name, ptype, value, textfile, binfile, command):
                 print("... executing command param [%s]" % command)
             import subprocess, shlex #shlex rocks
             try:
-                p = subprocess.Popen(shlex.split(command), stdout=subprocess.PIPE)
+                if os.name != 'nt':
+                    command = shlex.split(command)
+                else:
+                    # Python scripts in ROS tend to omit .py extension since they could become executable with shebang line
+                    # special handle the use of Python scripts in Windows environment:
+                    # 1. search for a wrapper executable (of the same name) under the same directory with stat.S_IXUSR flag
+                    # 2. if no wrapper is present, prepend command with 'python' executable
+
+                    cl = shlex.split(command, posix=False)  # use non-posix method on Windows
+                    if os.path.isabs(cl[0]):
+                        # trying to launch an executable from a specific location(package), e.g. xacro
+                        import stat
+                        rx_flag = stat.S_IRUSR | stat.S_IXUSR
+                        if not os.path.exists(cl[0]) or os.stat(cl[0]).st_mode & rx_flag != rx_flag:
+                            d = os.path.dirname(cl[0])
+                            files_of_same_name = [
+                                os.path.join(d, f) for f in os.listdir(d)
+                                if os.path.splitext(f)[0].lower() == os.path.splitext(os.path.basename(cl[0]))[0].lower()
+                            ] if os.path.exists(d) else []
+                            executable_command = None
+                            for f in files_of_same_name:
+                                if os.stat(f).st_mode & rx_flag == rx_flag:
+                                    # found an executable wrapper of the desired Python script
+                                    executable_command = f
+
+                            if not executable_command:
+                                for f in files_of_same_name:
+                                    mode = os.stat(f).st_mode
+                                    if (mode & stat.S_IRUSR == stat.S_IRUSR) and (mode & stat.S_IXUSR != stat.S_IXUSR):
+                                        # when there is read permission but not execute permission, this is typically a Python script (in ROS)
+                                        if os.path.splitext(f)[1].lower() in ['.py', '']:
+                                            executable_command = ' '.join([sys.executable, f])
+                            if executable_command:
+                                command = command.replace(cl[0], executable_command, 1)
+                p = subprocess.Popen(command, stdout=subprocess.PIPE)
                 c_value = p.communicate()[0]
                 if not isinstance(c_value, str):
                     c_value = c_value.decode('utf-8')