xpra control does not output error messages

[stdedos]

From #2338: Running:

$ xpra control 0 clipboard-direction help
$ 

Gives no output, but, in logs:

  72   │ 2019-06-19 12:22:45,821 error processing control command 'clipboard-direction'
  73   │ Traceback (most recent call last):
  74   │   File "/usr/lib/python2.7/dist-packages/xpra/server/server_core.py", line 672, in process_control_command
  75   │     v = command.run(*args[1:])
  76   │   File "/usr/lib/python2.7/dist-packages/xpra/server/control_command.py", line 69, in run
  77   │     return super(ArgsControlCommand, self).run(*args)
  78   │   File "/usr/lib/python2.7/dist-packages/xpra/server/control_command.py", line 31, in run
  79   │     return self.do_run(*args)
  80   │   File "/usr/lib/python2.7/dist-packages/xpra/server/mixins/server_base_controlcommands.py", line 452, in control_command_clipboard_direction
  81   │     assert direction in DIRECTIONS, "invalid direction '%s', must be one of %s" % (direction, csv(DIRECTIONS))
  82   │ AssertionError: invalid direction 'help', must be one of to-server, to-client, both, disabled

[stdedos]

I also got this from the client:

2019-06-19 12:24:05,877 unknown server setting changed: clipboard_direction="b'both'"

(I don't know if it helps with anything)

[Antoine Martin]

I see:

$ xpra control :2 clipboard-direction help
server returned error code 127
 error processing control command: invalid direction 'help', must be one of to-server, to-client, both, disabled

Which is fine.
I originally changed it in r22995, but r22996 reverts it to ensure that we return a non-zero exit code when things fail.

Please provide more details so I can reproduce: commands used, exact version, exit code, etc..

[stdedos]

Server version is v3.0-r22963. So, I guess you can close as already fixed?

[migration script]

this ticket has been moved to: ​https://github.com/Xpra-org/xpra/issues/2339