.

src/debugpy/launcher/debuggee.py

@@ -58,6 +58,10 @@ def spawn(process_name, cmdline, env, redirect_output):
             # all their subprocesses, so that the OS will kill the entire object tree
             # automatically when launcher exits.
             _setup_win32_job()
+        else:
+            # Start the debuggee in a new process group, so that the launcher can kill
+            # the entire group later.
+            kwargs.update(preexec_fn=os.setpgrp)
 
         try:
             global process
@@ -69,10 +73,8 @@ def spawn(process_name, cmdline, env, redirect_output):
 
         log.info("Spawned {0}.", describe())
 
+        # On Windows, the job object takes care of process tree cleanup. 
         if sys.platform != "win32":
-            # Assign the debuggee to a new process group, so that we can easily kill
-            # the entire group including subprocesses later.
-            os.setpgid(process.pid, 0)
             atexit.register(kill)
 
         launcher.channel.send_event(
@@ -109,17 +111,23 @@ def spawn(process_name, cmdline, env, redirect_output):
 def kill():
     if process is None:
         return
+
     try:
         if process.poll() is None:
             log.info("Killing {0}", describe())
             process.kill()
-            if sys.platform != "win32":
-                # On POSIX, we also kill the process group that we created for the
-                # debuggee, to kill all its subprocesses.
-                os.kill(-process.pid, signal.SIGKILL)
     except Exception:
         log.swallow_exception("Failed to kill {0}", describe())
 
+    if sys.platform != "win32":
+        # On POSIX, we also kill debuggee's process group, which kills the whole
+        # process tree (excepting subprocesses that joined another process group).
+        try:
+            log.info("Killing {0} process group", describe())
+            os.kill(-process.pid, signal.SIGKILL)
+        except Exception:
+            log.swallow_exception("Failed to kill {0} process group", describe())
+
 
 def wait_for_exit():
     try:

src/debugpy/launcher/handlers.py

@@ -64,6 +64,7 @@ def property_or_debug_option(prop_name, flag_name):
         adapter_access_token = request("adapterAccessToken", unicode, optional=True)
         if adapter_access_token != ():
             cmdline += ["--adapter-access-token", compat.filename(adapter_access_token)]
+
         debugpy_args = request("debugpyArgs", json.array(unicode))
         cmdline += debugpy_args