Pandas 1.0.0 breaks the result set. #1283
Description
When running the tests for the result set:
python -m unittest
with pandas 0.25.3 everything passes but with 1.0.0 we get errors:
File "/Users/vince/anaconda3/envs/axelrod/lib/python3.7/site-packages/dask/local.py", line 222, in execute_task
result = _execute_task(task, data)
File "/Users/vince/anaconda3/envs/axelrod/lib/python3.7/site-packages/dask/core.py", line 119, in _execute_task
return func(*args2)
File "/Users/vince/anaconda3/envs/axelrod/lib/python3.7/site-packages/dask/utils.py", line 29, in apply
return func(*args, **kwargs)
File "/Users/vince/anaconda3/envs/axelrod/lib/python3.7/site-packages/dask/dataframe/groupby.py", line 279, in _groupby_aggregate
return aggfunc(df.groupby(level=levels, sort=False, **dropna), **kwargs)
File "/Users/vince/anaconda3/envs/axelrod/lib/python3.7/site-packages/pandas/core/frame.py", line 5807, in groupby
observed=observed,
File "/Users/vince/anaconda3/envs/axelrod/lib/python3.7/site-packages/pandas/core/groupby/groupby.py", line 409, in __init__
mutated=self.mutated,
File "/Users/vince/anaconda3/envs/axelrod/lib/python3.7/site-packages/pandas/core/groupby/grouper.py", line 625, in get_grouper
if not isinstance(gpr, Grouping)
File "/Users/vince/anaconda3/envs/axelrod/lib/python3.7/site-packages/pandas/core/groupby/grouper.py", line 287, in __init__
) = index._get_grouper_for_level(self.grouper, level)
File "/Users/vince/anaconda3/envs/axelrod/lib/python3.7/site-packages/pandas/core/indexes/multi.py", line 1267, in _get_grouper_for_level
grouper = level_index.take(codes, fill_value=True)
File "/Users/vince/anaconda3/envs/axelrod/lib/python3.7/site-packages/pandas/core/indexes/base.py", line 761, in take
f"Unable to fill values because {cls_name} cannot contain NA"
ValueError: Unable to fill values because Int64Index cannot contain NA
This has happened on #1282.