What happened: A call to zarr storage to mino instance fails with newest s3fs storage (s3fs > 0.5.0) while perfectly working with s3fs == 0.4.0. Might be due to s3fs' reliance on aiobotocore as Traceback. Traceback (most recent call last): Exception in callback <TaskStepMethWrapper object at 0x7fbe34300350>() handle: <Handle <TaskStepMethWrapper object at 0x7fbe34300350>()> Traceback (most recent call last): File "/usr/local/lib/python3.7/asyncio/events.py", line 88, in _run self._context.run(self._callback, *self._args) RuntimeError: Leaving task <Task finished coro=<sync.<locals>.f() done, defined at /usr/local/lib/python3.7/site-packages/fsspec/asyn.py:43> result=None> does not match the current task None. File "test_without.py", line 27, in <module> array.to_dataset().to_zarr(store=s3store, mode="w", consolidated=True, compute=True) File "/usr/local/lib/python3.7/site-packages/xarray/core/dataset.py", line 1662, in to_zarr append_dim=append_dim, File "/usr/local/lib/python3.7/site-packages/xarray/backends/api.py", line 1369, in to_zarr writes = writer.sync(compute=compute) File "/usr/local/lib/python3.7/site-packages/xarray/backends/common.py", line 161, in sync regions=self.regions, File "/usr/local/lib/python3.7/site-packages/dask/array/core.py", line 981, in store result.compute(**kwargs) File "/usr/local/lib/python3.7/site-packages/dask/base.py", line 167, in compute (result,) = compute(self, traverse=False, **kwargs) File "/usr/local/lib/python3.7/site-packages/dask/base.py", line 452, in compute results = schedule(dsk, keys, **kwargs) File "/usr/local/lib/python3.7/site-packages/dask/threaded.py", line 84, in get **kwargs File "/usr/local/lib/python3.7/site-packages/dask/local.py", line 486, in get_async raise_exception(exc, tb) File "/usr/local/lib/python3.7/site-packages/dask/local.py", line 316, in reraise raise exc File "/usr/local/lib/python3.7/site-packages/dask/local.py", line 222, in execute_task result = _execute_task(task, data) File "/usr/local/lib/python3.7/site-packages/dask/core.py", line 121, in _execute_task return func(*(_execute_task(a, cache) for a in args)) File "/usr/local/lib/python3.7/site-packages/dask/array/core.py", line 3722, in store_chunk return load_store_chunk(x, out, index, lock, return_stored, False) File "/usr/local/lib/python3.7/site-packages/dask/array/core.py", line 3711, in load_store_chunk out[index] = np.asanyarray(x) File "/usr/local/lib/python3.7/site-packages/zarr/core.py", line 1115, in __setitem__ self.set_basic_selection(selection, value, fields=fields) File "/usr/local/lib/python3.7/site-packages/zarr/core.py", line 1210, in set_basic_selection return self._set_basic_selection_nd(selection, value, fields=fields) File "/usr/local/lib/python3.7/site-packages/zarr/core.py", line 1501, in _set_basic_selection_nd self._set_selection(indexer, value, fields=fields) File "/usr/local/lib/python3.7/site-packages/zarr/core.py", line 1550, in _set_selection self._chunk_setitem(chunk_coords, chunk_selection, chunk_value, fields=fields) File "/usr/local/lib/python3.7/site-packages/zarr/core.py", line 1665, in _chunk_setitem fields=fields) File "/usr/local/lib/python3.7/site-packages/zarr/core.py", line 1729, in _chunk_setitem_nosync self.chunk_store[ckey] = cdata File "/usr/local/lib/python3.7/site-packages/fsspec/mapping.py", line 150, in __setitem__ self.fs.mkdirs(self.fs._parent(key), exist_ok=True) File "/usr/local/lib/python3.7/site-packages/fsspec/spec.py", line 1066, in mkdirs return self.makedirs(path, exist_ok=exist_ok) File "/usr/local/lib/python3.7/site-packages/s3fs/core.py", line 488, in makedirs self.mkdir(path, create_parents=True) File "/usr/local/lib/python3.7/site-packages/fsspec/asyn.py", line 118, in wrapper return maybe_sync(func, self, *args, **kwargs) File "/usr/local/lib/python3.7/site-packages/fsspec/asyn.py", line 97, in maybe_sync return sync(loop, func, *args, **kwargs) File "/usr/local/lib/python3.7/site-packages/fsspec/asyn.py", line 68, in sync raise exc.with_traceback(tb) File "/usr/local/lib/python3.7/site-packages/fsspec/asyn.py", line 52, in f result[0] = await future File "/usr/local/lib/python3.7/site-packages/s3fs/core.py", line 462, in _mkdir if not key or (create_parents and not self.exists(bucket)): File "/usr/local/lib/python3.7/site-packages/fsspec/asyn.py", line 118, in wrapper return maybe_sync(func, self, *args, **kwargs) File "/usr/local/lib/python3.7/site-packages/fsspec/asyn.py", line 90, in maybe_sync return _run_until_done(func(*args, **kwargs)) File "/usr/local/lib/python3.7/site-packages/fsspec/asyn.py", line 28, in _run_until_done loop._run_once() File "/usr/local/lib/python3.7/asyncio/base_events.py", line 1771, in _run_once handle = self._ready.popleft() IndexError: pop from an empty deque What you expected to happen:

Storage succeeding. No Exception.

Minimal Complete Verifiable Example:

```python

Put your MCVE code here

import dask.array as da import xarray import s3fs import xarray as xr

bucket = "zarr" name = "sample"

nana = xarray.DataArray(da.zeros((1023,1023,3)))

s3_path = f"{bucket}/{name}" s3 = s3fs.S3FileSystem(client_kwargs={"endpoint_url": "s3://minio:9000"}, username="weak_access_key", password="weak_secret_key") s3store = s3.get_mapper(s3_path)

print("Storing") nana.to_dataset().to_zarr(store=s3store, mode="w", consolidated=True, compute=True) print("Getting") ```

Anything else we need to know?:

Thanks and keep up the great work!

Environment:

dask==2.28.0 xarray==0.16.1 aiobotocore==1.1.1 fsspec==0.8.3 zarr==2.4.0 s3fs==0.5.1

Output of <tt>xr.show_versions()</tt>

INSTALLED VERSIONS ------------------ commit: None python: 3.7.8 (default, Jun 30 2020, 18:27:23) [GCC 8.3.0] python-bits: 64 OS: Linux OS-release: 4.19.104-microsoft-standard machine: x86_64 processor: byteorder: little LC_ALL: None LANG: C.UTF-8 LOCALE: en_US.UTF-8 libhdf5: None libnetcdf: None xarray: 0.16.1 pandas: 1.1.2 numpy: 1.19.2 scipy: 1.5.2 netCDF4: None pydap: None h5netcdf: None h5py: None Nio: None zarr: 2.4.0 cftime: None nc_time_axis: None PseudoNetCDF: None rasterio: None cfgrib: None iris: None bottleneck: None dask: 2.28.0 distributed: 2.28.0 matplotlib: 3.3.2 cartopy: None seaborn: 0.11.0 numbagg: None pint: None setuptools: 47.3.1 pip: 20.1.1 conda: None pytest: 6.1.0 IPython: 7.18.1 sphinx: None