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
501108453,MDU6SXNzdWU1MDExMDg0NTM=,3363,user-friendly additions for dask usage,2448579,closed,0,,,3,2019-10-01T19:48:27Z,2021-04-19T03:34:18Z,2021-04-19T03:34:18Z,MEMBER,,,,"Any thoughts on adding

1. `.chunksize` or `.nbytes_chunk`
2. `.ntasks` : this would be `len(obj.__dask_graph__())`","{""url"": ""https://api.github.com/repos/pydata/xarray/issues/3363/reactions"", ""total_count"": 0, ""+1"": 0, ""-1"": 0, ""laugh"": 0, ""hooray"": 0, ""confused"": 0, ""heart"": 0, ""rocket"": 0, ""eyes"": 0}",,completed,13221727,issue
501150299,MDExOlB1bGxSZXF1ZXN0MzIzNDgwMDky,3364,Make concat more forgiving with variables that are being merged.,2448579,closed,0,,,3,2019-10-01T21:15:54Z,2019-10-17T01:30:32Z,2019-10-14T18:06:54Z,MEMBER,,0,pydata/xarray/pulls/3364,"<!-- Feel free to remove check-list items aren't relevant to your change -->

 - [x] Closes #508
 - [x] Tests added
 - [x] Passes `black . && mypy . && flake8`
 - [x] Fully documented, including `whats-new.rst` for all changes and `api.rst` for new API

Downstream issue: https://github.com/marbl-ecosys/cesm2-marbl/issues/1

Basically, we are currently raising an error when attempting to merge variables that are present in some datasets but not others that are provided to concat. This seems unnecessarily strict and it turns out we had an issue for it! (#508)
","{""url"": ""https://api.github.com/repos/pydata/xarray/issues/3364/reactions"", ""total_count"": 2, ""+1"": 2, ""-1"": 0, ""laugh"": 0, ""hooray"": 0, ""confused"": 0, ""heart"": 0, ""rocket"": 0, ""eyes"": 0}",,,13221727,pull
501059947,MDExOlB1bGxSZXF1ZXN0MzIzNDA1OTEz,3362,Fix concat bug when concatenating unlabeled dimensions.,2448579,closed,0,,,3,2019-10-01T18:10:22Z,2019-10-08T22:30:38Z,2019-10-08T22:13:48Z,MEMBER,,0,pydata/xarray/pulls/3362,"<!-- Feel free to remove check-list items aren't relevant to your change -->

This fixes the following behaviour. (downstream issue https://github.com/xgcm/xgcm/issues/154)

```
def test_concat(self, data):
        split_data = [
            data.isel(dim1=slice(3)),
            data.isel(dim1=3), # this wouldn't work on master
            data.isel(dim1=slice(4, None)),
        ]
        assert_identical(data, concat(split_data, ""dim1""))
```","{""url"": ""https://api.github.com/repos/pydata/xarray/issues/3362/reactions"", ""total_count"": 0, ""+1"": 0, ""-1"": 0, ""laugh"": 0, ""hooray"": 0, ""confused"": 0, ""heart"": 0, ""rocket"": 0, ""eyes"": 0}",,,13221727,pull