Multiple methods fail on a DataArray with scalar dimension

[suyashbire1]

Code Sample, a copy-pastable example if possible

import numpy as np
import xarray as xr
a = np.arange(20).reshape(1,2,2,5)
coords = dict(t=0, z=np.arange(2), y=np.arange(2), x=np.arange(5))
b = xr.DataArray(a,dims=['t', 'z', 'y', 'x'],coords=coords)
b.squeeze() # Throws ValueError: dimension 't' already exists as a scalar variable

coords = dict(t=[0], z=np.arange(2), y=np.arange(2), x=np.arange(5))
c = xr.DataArray(a,dims=['t', 'z', 'y', 'x'],coords=coords)
c.squeeze()  # This works!

Problem description

Besides squeeze, a number of other methods like drop fail on DataArray b. Since, scalar dimensions are not dropped, it is almost impossible to do anything useful like plot, concat, etc with b. All these methods fail with ValueError: dimension 't' already exists as a scalar variable.

Expected Output

In my opinion, b and c should behave in the same way. It would just involve converting the scalar dimensions into lists. Is this behavior a bug or by design?

Output of xr.show_versions()

0.9.6

[shoyer]

Thanks for the report.

This should actually raise an error at construction time for the DataArray. Variables with names matching dimensions are special in xarray: they are required to be 1D arrays with length matching the dimension size.

[suyashbire1]

Glad I could help.