issues: 365526259

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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
365526259 MDU6SXNzdWUzNjU1MjYyNTk= 2451 Shift changes non-float arrays to object, even for shift=0 5635139 closed 0     2 2018-10-01T15:50:38Z 2019-03-04T16:31:57Z 2019-03-04T16:31:57Z MEMBER      

```python In [15]: xr.DataArray(np.random.randint(2,size=(100,100)).astype(bool)).shift(dim_0=0) Out[15]: <xarray.DataArray (dim_0: 100, dim_1: 100)> array([[False, True, True, ..., True, True, False], [False, True, False, ..., False, True, True], [False, True, False, ..., False, True, False], ..., [False, True, False, ..., False, True, True], [True, False, True, ..., False, False, False], [False, True, True, ..., True, True, False]], dtype=object) # <-- could be bool Dimensions without coordinates: dim_0, dim_1

```

Problem description

This causes memory bloat

Expected Output

As above with dtype=bool

Output of xr.show_versions()

In [16]: xr.show_versions() INSTALLED VERSIONS ------------------ commit: f9c4169150286fa1aac020ab965380ed21fe1148 python: 2.7.15.final.0 python-bits: 64 OS: Darwin OS-release: 18.0.0 machine: x86_64 processor: i386 byteorder: little LC_ALL: None LANG: en_US.UTF-8 LOCALE: None.None xarray: 0.10.9+12.gf9c41691 pandas: 0.22.0 numpy: 1.14.2 scipy: 1.0.0 netCDF4: None h5netcdf: None h5py: None Nio: None zarr: None cftime: None PseudonetCDF: None rasterio: None iris: None bottleneck: 1.2.1 cyordereddict: None dask: None distributed: None matplotlib: 2.1.2 cartopy: None seaborn: 0.8.1 setuptools: 39.2.0 pip: 18.0 conda: None pytest: 3.6.3 IPython: 5.8.0 sphinx: None

The shift=0 is mainly theoretical. To avoid casting to object in practical scenarios, we could add a fill_value argument (e.g. fill_value=False) and fill with that rather than NaN

CC @Ivocrnkovic

 
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   completed 13221727 issue

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