id,node_id,number,title,user,state,locked,assignee,milestone,comments,created_at,updated_at,closed_at,author_association,active_lock_reason,draft,pull_request,body,reactions,performed_via_github_app,state_reason,repo,type
811321550,MDU6SXNzdWU4MTEzMjE1NTA=,4922,Bottleneck and dask objects ignore `min_periods` on `rolling`,8881170,open,0,,,5,2021-02-18T17:43:50Z,2021-12-19T15:18:45Z,,CONTRIBUTOR,,,,"**What happened**:

When `bottleneck` is installed in an environment, it seems to ignore the `min_periods` kwarg on `ds.rolling(...)`.

**What you expected to happen**:

When using `ds.rolling(..., min_periods=1)`, it should be able to handle an array of length 1. Without `bottleneck` installed, it returns the original value of a length 1 array. With `bottleneck` installed, the error is:

```python-traceback
ValueError: Moving window (=2) must between 1 and 1, inclusive
```

**Minimal Complete Verifiable Example**:

With `bottleneck` installed to environment:

```python
import xarray as xr
ds = xr.DataArray([1], dims='time')
ds.rolling(time=2, center=True, min_periods=1).mean()
```

```python-traceback
ValueError: Moving window (=2) must between 1 and 1, inclusive
```

Without `bottleneck` installed to environment:

```python
import xarray as xr
ds = xr.DataArray([1], dims='time')
ds.rolling(time=2, center=True, min_periods=1).mean()

>>> <xarray.DataArray (time: 1)>
>>> array([1.])
>>> Dimensions without coordinates: time
```

**Anything else we need to know?**:

In an applied case, this came up while working on `.groupby('time.dayofyear').map(_rolling)`, where we map a rolling mean function over a defined N days with `min_periods=1`. Some climatological days (like leap years) will not have the N day requirement, so the `min_period` catch handles that, but with `bottleneck` installed it breaks due to the above issue.

**Environment**:

<details><summary>Output of <tt>xr.show_versions()</tt></summary>
INSTALLED VERSIONS
------------------
commit: None
python: 3.8.6 | packaged by conda-forge | (default, Jan 25 2021, 23:22:12) 
[Clang 11.0.1 ]
python-bits: 64
OS: Darwin
OS-release: 19.6.0
machine: x86_64
processor: i386
byteorder: little
LC_ALL: en_US.UTF-8
LANG: en_US.UTF-8
LOCALE: en_US.UTF-8
libhdf5: 1.10.6
libnetcdf: 4.7.4

xarray: 0.16.2
pandas: 1.2.1
numpy: 1.19.5
scipy: 1.6.0
netCDF4: 1.5.5.1
pydap: None
h5netcdf: 0.8.1
h5py: 3.1.0
Nio: None
zarr: 2.6.1
cftime: 1.3.1
nc_time_axis: 1.2.0
PseudoNetCDF: None
rasterio: 1.1.8
cfgrib: None
iris: None
bottleneck: 1.3.2
dask: 2021.01.1
distributed: 2021.01.1
matplotlib: 3.3.3
cartopy: 0.18.0
seaborn: 0.11.1
numbagg: None
pint: 0.16.1
setuptools: 49.6.0.post20210108
pip: 21.0
conda: None
pytest: 6.2.2
IPython: 7.18.1
sphinx: 3.4.3
</details>
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