remote/client: suppress gRPC error message on shutdown

This is a workround for the gRPC issue
grpc/grpc#38679.

Since Python 3.12, an empty exception message is printed from gRPC during
shutdown, although nothing seems to go wrong. As this is confusing for
users, suppress the message by closing stderr. When in debug mode, we
keep it open.

Signed-off-by: Jan Luebbe <[email protected]>

Author: jluebbe

labgrid/remote/client.py

@@ -2169,6 +2169,13 @@ def main():
         except Exception:  # pylint: disable=broad-except
             traceback.print_exc(file=sys.stderr)
             exitcode = 2
+        if not args.debug:
+            # This is a workround for the gRPC issue
+            # https://github.com/grpc/grpc/issues/38679.
+            # Since Python 3.12, an empty exception message is printed from gRPC
+            # during shutdown, although nothing seems to go wrong. As this is
+            # confusing for users, suppress the message by closing stderr.
+            os.close(sys.stderr.fileno())
         exit(exitcode)
     else:
         parser.print_help(file=sys.stderr)