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
1672146474,I_kwDOAMm_X85jqu4q,7763,xr.concat error behaviour differs based on input DataArray ordering,5311739,open,0,,,1,2023-04-18T00:13:27Z,2023-04-24T16:04:37Z,,NONE,,,,"### What happened?

When using `xr.concat` without specifying the coords argument and with input DataArrays of differing dimensions, where one is missing a dimension that is present in the others, the behaviour of the function will depend on the order and number of the arrays in the input list. The expected behaviour is that a ValueError prompting the use of coords='minimal' will be raised, however this error is not raised when either:
* There are only two DataArrays in the provided list; or
* The DataArray with the missing dimension is first in the list.

In these instances, the `xr.concat` function acts as if coords='minimal' has been specified and broadcasts the smaller DataArray without erroring.

### What did you expect to happen?

The raising of errors when using `xr.concat` should be consistent and not depend on the ordering or number of inputs.

### Minimal Complete Verifiable Example

```Python
a = xr.DataArray([[1,2,3],[4,5,6]], coords=[('first', [10, 20]), ('second', ['a', 'b', 'c'])])
b = xr.DataArray([[10,20,30],[40,50,60]], coords=[('first', [30, 40]), ('second', ['a', 'b', 'c'])])
c = xr.DataArray([100, 200], coords=[('first', [10, 20])])

xr.concat([a, b, c], dim='first')  # Errors as expected
xr.concat([b, a, c], dim='first')  # Errors as expected
xr.concat([c, a, b], dim='first')  # Does not error
xr.concat([a, c], dim='first')     # Does not error
xr.concat([c, a], dim='first')     # Does not error
```


### MVCE confirmation

- [X] Minimal example — the example is as focused as reasonably possible to demonstrate the underlying issue in xarray.
- [X] Complete example — the example is self-contained, including all data and the text of any traceback.
- [X] Verifiable example — the example copy & pastes into an IPython prompt or [Binder notebook](https://mybinder.org/v2/gh/pydata/xarray/main?urlpath=lab/tree/doc/examples/blank_template.ipynb), returning the result.
- [X] 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

<details>

INSTALLED VERSIONS
------------------
commit: None
python: 3.10.11 (main, Apr  5 2023, 14:15:10) [GCC 9.4.0]
python-bits: 64
OS: Linux
OS-release: 5.15.90.1-microsoft-standard-WSL2
machine: x86_64
processor: x86_64
byteorder: little
LC_ALL: None
LANG: C.UTF-8
LOCALE: ('en_US', 'UTF-8')
libhdf5: None
libnetcdf: None

xarray: 2023.4.0
pandas: 2.0.0
numpy: 1.24.2
scipy: None
netCDF4: None
pydap: None
h5netcdf: None
h5py: None
Nio: None
zarr: None
cftime: None
nc_time_axis: None
PseudoNetCDF: None
iris: None
bottleneck: None
dask: None
distributed: None
matplotlib: None
cartopy: None
seaborn: None
numbagg: None
fsspec: None
cupy: None
pint: None
sparse: None
flox: None
numpy_groupies: None
setuptools: 65.3.0
pip: 22.2.2
conda: None
pytest: None
mypy: None
IPython: 8.12.0
sphinx: None

</details>
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