Coordinates not deep copy

What happened?

The coordinates are not copied if you perform deepcopy for xarray.
This issue was fixed before. I don't see it, for example, in xarray 2022.12.0, but in the latest version the issue is there again.

import xarray as xr

xarr1 = xr.DataArray(
    np.zeros([2]), 
    coords=dict(x=[0.0, 1.0]), # important to use 'float' here! with 'int' it is working fine
    dims=("x")
)
print(xarr1.x.data[0]) # 0.0

xarr2 = xarr1.copy(deep=True)
xarr2.x.data[0] = 45
print(xarr1.x.data[0]) # gives 45

Interesting, that if your coordinates are int, then the issue is gone

What did you expect to happen?

import xarray as xr

xarr1 = xr.DataArray(
    np.zeros([2]), 
    coords=dict(x=[0.0, 1.0]), # important to use 'float' here! with 'int' it is working fine
    dims=("x")
)
print(xarr1.x.data[0]) # 0.0

xarr2 = xarr1.copy(deep=True)
xarr2.x.data[0] = 45
print(xarr1.x.data[0]) # I expect it to be 0.0

Minimal Complete Verifiable Example

import xarray as xr

xarr1 = xr.DataArray(
    np.zeros([2]), 
    coords=dict(x=[0.0, 1.0]), # important to use 'float' here! with 'int' it is working fine
    dims=("x")
)
print(xarr1.x.data[0]) # 0.0

xarr2 = xarr1.copy(deep=True)
xarr2.x.data[0] = 45
print(xarr1.x.data[0]) # gives 45

MVCE confirmation

• Minimal example — the example is as focused as reasonably possible to demonstrate the underlying issue in xarray.
• Complete example — the example is self-contained, including all data and the text of any traceback.
• Verifiable example — the example copy & pastes into an IPython prompt or Binder notebook, returning the result.
• New issue — a search of GitHub Issues suggests this is not a duplicate.

Relevant log output

No response

Anything else we need to know?

No response

Environment

Start by running the reported DataArray deep-copy example against the current xarray version and compare the float-coordinate behavior with integer coordinates. Trace the copy path involved in coordinate data and add a regression test showing that changing xarr2.x.data does not change xarr1.x.data; done when the original remains 0.0.