html_url,issue_url,id,node_id,user,created_at,updated_at,author_association,body,reactions,performed_via_github_app,issue
https://github.com/pydata/xarray/issues/508#issuecomment-553993804,https://api.github.com/repos/pydata/xarray/issues/508,553993804,MDEyOklzc3VlQ29tbWVudDU1Mzk5MzgwNA==,775186,2019-11-14T17:30:09Z,2019-11-14T17:30:09Z,CONTRIBUTOR,"Ok got it, I'll take a look and spin up a PR.  
Thanks","{""total_count"": 0, ""+1"": 0, ""-1"": 0, ""laugh"": 0, ""hooray"": 0, ""confused"": 0, ""heart"": 0, ""rocket"": 0, ""eyes"": 0}",,98587746
https://github.com/pydata/xarray/issues/508#issuecomment-553709888,https://api.github.com/repos/pydata/xarray/issues/508,553709888,MDEyOklzc3VlQ29tbWVudDU1MzcwOTg4OA==,775186,2019-11-14T03:37:59Z,2019-11-14T04:09:02Z,CONTRIBUTOR,"I just ran in to this issue. While the previous fix seems to handle one case it doesn't handle all the cases.  Before I clean this up and open a new PR does this look like its on the right track (it worked for my issue where I was concating multiple datasets which always had the same dims and coordinates but sometimes were missing variables)?

starts at line 353 on concat.py
 ```
 for k in datasets[0].variables:
        if k in concat_over:
            try:
                #new code
                for ds in datasets:
                    if k not in ds.variables:
                        #make a new array with the same dimensions and coordinates
                        #by default this will be initialized to np.nan which is what we want
                        from .dataarray import DataArray
                        new_array = DataArray(coords=ds.coords, dims=ds.dims)
                        ds[k] = new_array
                #end new code
                vars = ensure_common_dims([ds.variables[k] for ds in datasets])
            except KeyError: 
               #this can likely be removed then
                raise ValueError(""%r is not present in all datasets."" % k)
            combined = concat_vars(vars, dim, positions)
            assert isinstance(combined, Variable)
            result_vars[k] = combined
```","{""total_count"": 0, ""+1"": 0, ""-1"": 0, ""laugh"": 0, ""hooray"": 0, ""confused"": 0, ""heart"": 0, ""rocket"": 0, ""eyes"": 0}",,98587746