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
495869721,MDU6SXNzdWU0OTU4Njk3MjE=,3323,arithmetic resulting in inconsistent chunks,2448579,closed,0,,,2,2019-09-19T15:21:30Z,2019-10-10T23:44:19Z,2019-10-10T23:44:19Z,MEMBER,,,,"``` python

import xarray as xr
import numpy as np

def make_da():
    return xr.DataArray(
        np.ones((10, 20)),
        dims=[""x"", ""y""],
        coords={""x"": np.arange(10), ""y"": np.arange(100, 120),},
        name=""a"",
    ).chunk({""x"": 4, ""y"": 5})

map_da = make_da()
map_ds = xr.Dataset()
map_ds[""a""] = make_da()
map_ds[""c""] = map_ds.x + 20
map_ds = map_ds.chunk({""x"": 4, ""y"": 5})
```


```
<xarray.Dataset>
Dimensions:  (x: 10, y: 20)
Coordinates:
  * x        (x) int64 0 1 2 3 4 5 6 7 8 9
  * y        (y) int64 100 101 102 103 104 105 106 ... 114 115 116 117 118 119
Data variables:
    a        (x, y) float64 dask.array<chunksize=(4, 5), meta=np.ndarray>
    c        (x) int64 dask.array<chunksize=(4,), meta=np.ndarray>
```

`(map_ds + map_ds.y)` gives `y` chunksize of 20 for `c` and 5 for `a`

```
(map_ds + map_ds.y)
<xarray.Dataset>
Dimensions:  (x: 10, y: 20)
Coordinates:
  * x        (x) int64 0 1 2 3 4 5 6 7 8 9
  * y        (y) int64 100 101 102 103 104 105 106 ... 114 115 116 117 118 119
Data variables:
    a        (x, y) float64 dask.array<chunksize=(4, 5), meta=np.ndarray>
    c        (x, y) int64 dask.array<chunksize=(4, 20), meta=np.ndarray>
```

This seems reasonable except `(map_ds + map_ds.y).chunks)` raises an ""Inconsistent chunks"" error.

I ran into this writing tests for map_blocks.","{""url"": ""https://api.github.com/repos/pydata/xarray/issues/3323/reactions"", ""total_count"": 0, ""+1"": 0, ""-1"": 0, ""laugh"": 0, ""hooray"": 0, ""confused"": 0, ""heart"": 0, ""rocket"": 0, ""eyes"": 0}",,completed,13221727,issue