fix trying to restart threads when connecting multiple times

[toebsen]

When trying to connect e.g. via UDP to a XCP slave which is not responding, the default error handler will try to reconnect infinite times. In some scenarios this is not sensible. Therefore, I've disabled the error handler.

This unfortunately leads to a RuntimeError: threads can only be started once from self._packet_listener.start() in the transport.connect()

I've fixed this for all the relevant transports, but only verified that it works with the ethernet transport. Possible repro script:

import threading
import time

import pyxcp

master = pyxcp.Master("eth",
                      config={
                          "HOST": "127.0.0.1",
                          "PROTOCOL": "UDP",
                          "DISABLE_ERROR_HANDLING": True,
                          "LOGLEVEL": "DEBUG"
                      })

for _ in range(5):
    try:
        master.connect()
    except pyxcp.types.XcpTimeoutError as exc:
        print(exc)

With the proposed changes it is possible to call the connect multiple times, when the error handler is disabled.

Types of changes

• [x] Bug fix (non-breaking change which fixes an issue)
• [ ] New feature (non-breaking change which adds functionality)
• [ ] Breaking change (fix or feature that would cause existing functionality to change)
• [x] I have read the CONTRIBUTING document.
• [x] My code follows the code style of this project.
• [ ] My change requires a change to the documentation.
• [ ] I have updated the documentation accordingly.
• [ ] I have added tests to cover my changes.
• [x] All new and existing tests passed.

[christoph2]

OK, looks good -- I think the other transports are not affected of this pesky problem.

[toebsen]

@christoph2 Thanks for merging. It seems that the deploy to pypi failed: https://github.com/christoph2/pyxcp/actions/runs/6509156789/job/17680708294. Can you please take a look?

[christoph2]

OK, now available as 0.21.6 on PyPI. The small problem is/was the lack of documentation -- If you submit a PR bumpversion patch is required, otherwise the upload_pypi action is faced with an already existing version on PyPI and fails. I'm currently working on a larger update, hopefully including documentation (definitely including high-level measurement functions)...