Click dependency problem with latest version (8.0.0)

What happened: Error when calling dask-scheduler or dask-worker

What you expected to happen: Not an error

Minimal Complete Verifiable Example:

# Start from a blank python 3.8 environment
$ pip install distributed
# installs click 8.0.0 as a dependency

$ dask-scheduler --help
Traceback (most recent call last):
  File "/Users/nmerket/opt/anaconda3/envs/tempdask/bin/dask-scheduler", line 5, in <module>
    from distributed.cli.dask_scheduler import go
  File "/Users/nmerket/opt/anaconda3/envs/tempdask/lib/python3.8/site-packages/distributed/cli/dask_scheduler.py", line 120, in <module>
    def main(
  File "/Users/nmerket/opt/anaconda3/envs/tempdask/lib/python3.8/site-packages/click/decorators.py", line 247, in decorator
    _param_memo(f, OptionClass(param_decls, **option_attrs))
  File "/Users/nmerket/opt/anaconda3/envs/tempdask/lib/python3.8/site-packages/click/core.py", line 2467, in __init__
    super().__init__(param_decls, type=type, multiple=multiple, **attrs)
  File "/Users/nmerket/opt/anaconda3/envs/tempdask/lib/python3.8/site-packages/click/core.py", line 2106, in __init__
    raise ValueError(
ValueError: 'default' must be a list when 'multiple' is true.

$ dask-worker --help
Traceback (most recent call last):
  File "/Users/nmerket/opt/anaconda3/envs/tempdask/bin/dask-worker", line 8, in <module>
    sys.exit(go())
  File "/Users/nmerket/opt/anaconda3/envs/tempdask/lib/python3.8/site-packages/distributed/cli/dask_worker.py", line 461, in go
    check_python_3()
  File "/Users/nmerket/opt/anaconda3/envs/tempdask/lib/python3.8/site-packages/distributed/cli/utils.py", line 32, in check_python_3
    _unicodefun._verify_python3_env()
AttributeError: module 'click._unicodefun' has no attribute '_verify_python3_env'

Anything else we need to know?:

If I downgrade click to 7.1.2, it works as expected.

Environment:

• Dask version: 2021.4.1
• Python version: 3.7, 3.8
• Operating System: Mac, CentOS
• Install method (conda, pip, source): pip or conda (conda-forge)

certifi==2020.12.5
click==8.0.0
cloudpickle==1.6.0
dask==2021.4.1
distributed==2021.4.1
fsspec==2021.4.0
HeapDict==1.0.1
locket==0.2.1
msgpack==1.0.2
partd==1.2.0
psutil==5.8.0
PyYAML==5.4.1
sortedcontainers==2.3.0
tblib==1.7.0
toolz==0.11.1
tornado==6.1
zict==2.0.0

[jrbourbeau]

Thanks for reporting this issue @nmerket! There’s a new release of distributed coming out tomorrow which includes updates to support click >= 8.0.0 (xref https://github.com/dask/distributed/pull/4810).

Additionally, we’ve recently patched all existing distributed releases on conda-forge to pin click < 8. If you’re using pip to install distributed from PyPI, could you please manually pin click < 8 until the distributed release tomorrow. Thanks!

[fredms]

It works now. I tried a different machine.