keyerror in dask.config.rename when working with distributed

[bolliger32]

calling dask-worker using dask==1.2.2, distributed==1.28.1, I get the following error:

Traceback (most recent call last): File "/opt/conda/envs/worker/bin/dask-worker", line 7, in <module> from distributed.cli.dask_worker import go File "/opt/conda/envs/worker/lib/python3.6/site-packages/distributed/__init__.py", line 3, in <module> from . import config File "/opt/conda/envs/worker/lib/python3.6/site-packages/distributed/config.py", line 55, in <module> dask.config.rename(aliases) File "/opt/conda/envs/worker/lib/python3.6/site-packages/dask/config.py", line 451, in rename del config[k] # TODO: support nested keys KeyError: 'tick-maximum-delay'

It looks like this was introduced by #4742 when dask.config.rename was not properly adjusted, so that it can run into these KeyErrors. Current state of the function:

    """ Rename old keys to new keys
    This helps migrate older configuration versions over time
    """
    old = []
    new = {}
    for o, n in aliases.items():
        value = get(o, None, config=config)
        if value is not None:
            old.append(o)
            new[n] = value

    for k in old:
        del config[k]  # TODO: support nested keys

    set(new, config=config)

Suggest changing the 3rd to last line to del config[canonical_name(k, config)]. Will file an appropriate PR.