issues: 499477368

MCVE Code Sample

Example 1

```python import xarray as xr import numpy as np

da = xr.DataArray(np.random.randn(10, 20), name="a") ds = da.to_dataset() xr.testing.assert_equal(da, da.chunk({"dim_0": 2})) # works xr.testing.assert_equal(da.chunk(), da.chunk({"dim_0": 2})) # works

xr.testing.assert_equal(ds, ds.chunk({"dim_0": 2})) # works xr.testing.assert_equal(ds.chunk(), ds.chunk({"dim_0": 2})) # does not work

``` I get

```

ValueError Traceback (most recent call last) <ipython-input-1-bc8216a67408> in <module> 8 9 xr.testing.assert_equal(ds, ds.chunk({"dim_0": 2})) # works ---> 10 xr.testing.assert_equal(ds.chunk(), ds.chunk({"dim_0": 2})) # does not work

~/work/python/xarray/xarray/testing.py in assert_equal(a, b) 56 assert a.equals(b), formatting.diff_array_repr(a, b, "equals") 57 elif isinstance(a, Dataset): ---> 58 assert a.equals(b), formatting.diff_dataset_repr(a, b, "equals") 59 else: 60 raise TypeError("{} not supported by assertion comparison".format(type(a)))

~/work/python/xarray/xarray/core/dataset.py in equals(self, other) 1322 """ 1323 try: -> 1324 return self._all_compat(other, "equals") 1325 except (TypeError, AttributeError): 1326 return False

~/work/python/xarray/xarray/core/dataset.py in _all_compat(self, other, compat_str) 1285 1286 return self._coord_names == other._coord_names and utils.dict_equiv( -> 1287 self._variables, other._variables, compat=compat 1288 ) 1289

~/work/python/xarray/xarray/core/utils.py in dict_equiv(first, second, compat) 335 """ 336 for k in first: --> 337 if k not in second or not compat(first[k], second[k]): 338 return False 339 for k in second:

~/work/python/xarray/xarray/core/dataset.py in compat(x, y) 1282 # require matching order for equality 1283 def compat(x: Variable, y: Variable) -> bool: -> 1284 return getattr(x, compat_str)(y) 1285 1286 return self._coord_names == other._coord_names and utils.dict_equiv(

~/work/python/xarray/xarray/core/variable.py in equals(self, other, equiv) 1558 try: 1559 return self.dims == other.dims and ( -> 1560 self._data is other._data or equiv(self.data, other.data) 1561 ) 1562 except (TypeError, AttributeError):

~/work/python/xarray/xarray/core/duck_array_ops.py in array_equiv(arr1, arr2) 201 warnings.filterwarnings("ignore", "In the future, 'NAT == x'") 202 flag_array = (arr1 == arr2) | (isnull(arr1) & isnull(arr2)) --> 203 return bool(flag_array.all()) 204 205

~/miniconda3/envs/dcpy/lib/python3.7/site-packages/dask/array/core.py in bool(self) 1380 ) 1381 else: -> 1382 return bool(self.compute()) 1383 1384 nonzero = bool # python 2

~/miniconda3/envs/dcpy/lib/python3.7/site-packages/dask/base.py in compute(self, kwargs) 173 dask.base.compute 174 """ --> 175 (result,) = compute(self, traverse=False, kwargs) 176 return result 177

~/miniconda3/envs/dcpy/lib/python3.7/site-packages/dask/base.py in compute(args, kwargs) 444 keys = [x.dask_keys() for x in collections] 445 postcomputes = [x.dask_postcompute() for x in collections] --> 446 results = schedule(dsk, keys, kwargs) 447 return repack([f(r, a) for r, (f, a) in zip(results, postcomputes)]) 448

~/miniconda3/envs/dcpy/lib/python3.7/site-packages/dask/threaded.py in get(dsk, result, cache, num_workers, pool, kwargs) 80 get_id=_thread_get_id, 81 pack_exception=pack_exception, ---> 82 kwargs 83 ) 84

~/miniconda3/envs/dcpy/lib/python3.7/site-packages/dask/local.py in get_async(apply_async, num_workers, dsk, result, cache, get_id, rerun_exceptions_locally, pack_exception, raise_exception, callbacks, dumps, loads, **kwargs) 489 _execute_task(task, data) # Re-execute locally 490 else: --> 491 raise_exception(exc, tb) 492 res, worker_id = loads(res_info) 493 state["cache"][key] = res

~/miniconda3/envs/dcpy/lib/python3.7/site-packages/dask/compatibility.py in reraise(exc, tb) 128 if exc.traceback is not tb: 129 raise exc.with_traceback(tb) --> 130 raise exc 131 132 import pickle as cPickle

~/miniconda3/envs/dcpy/lib/python3.7/site-packages/dask/local.py in execute_task(key, task_info, dumps, loads, get_id, pack_exception) 231 try: 232 task, data = loads(task_info) --> 233 result = _execute_task(task, data) 234 id = get_id() 235 result = dumps((result, id))

~/miniconda3/envs/dcpy/lib/python3.7/site-packages/dask/core.py in _execute_task(arg, cache, dsk) 117 func, args = arg[0], arg[1:] 118 args2 = [_execute_task(a, cache) for a in args] --> 119 return func(*args2) 120 elif not ishashable(arg): 121 return arg

~/miniconda3/envs/dcpy/lib/python3.7/site-packages/dask/optimization.py in call(self, *args) 1057 if not len(args) == len(self.inkeys): 1058 raise ValueError("Expected %d args, got %d" % (len(self.inkeys), len(args))) -> 1059 return core.get(self.dsk, self.outkey, dict(zip(self.inkeys, args))) 1060 1061 def reduce(self):

~/miniconda3/envs/dcpy/lib/python3.7/site-packages/dask/core.py in get(dsk, out, cache) 147 for key in toposort(dsk): 148 task = dsk[key] --> 149 result = _execute_task(task, cache) 150 cache[key] = result 151 result = _execute_task(out, cache)

~/miniconda3/envs/dcpy/lib/python3.7/site-packages/dask/core.py in _execute_task(arg, cache, dsk) 117 func, args = arg[0], arg[1:] 118 args2 = [_execute_task(a, cache) for a in args] --> 119 return func(*args2) 120 elif not ishashable(arg): 121 return arg

ValueError: operands could not be broadcast together with shapes (0,20) (2,20) ```

Example 2

The relevant xarray line in the previous traceback is flag_array = (arr1 == arr2) | (isnull(arr1) & isnull(arr2)), so I tried

python (ds.isnull() & ds.chunk({"dim_0": 1}).isnull()).compute() # works (ds.chunk().isnull() & ds.chunk({"dim_0": 1}).isnull()).compute() # does not work?!

```

ValueError Traceback (most recent call last) <ipython-input-4-abdfbeda355a> in <module> 1 (ds.isnull() & ds.chunk({"dim_0": 1}).isnull()).compute() # works ----> 2 (ds.chunk().isnull() & ds.chunk({"dim_0": 1}).isnull()).compute() # does not work?!

~/work/python/xarray/xarray/core/dataset.py in compute(self, kwargs) 791 """ 792 new = self.copy(deep=False) --> 793 return new.load(kwargs) 794 795 def _persist_inplace(self, **kwargs) -> "Dataset":

~/work/python/xarray/xarray/core/dataset.py in load(self, **kwargs) 645 646 for k, data in zip(lazy_data, evaluated_data): --> 647 self.variables[k].data = data 648 649 # load everything else sequentially

~/work/python/xarray/xarray/core/variable.py in data(self, data) 331 data = as_compatible_data(data) 332 if data.shape != self.shape: --> 333 raise ValueError("replacement data must match the Variable's shape") 334 self._data = data 335

ValueError: replacement data must match the Variable's shape ```

Problem Description

I don't know what's going on here. I expect assert_equal should return True for all these examples.

Our test for isnull with dask always calls load before comparing:

def test_isnull_with_dask(): da = construct_dataarray(2, np.float32, contains_nan=True, dask=True) assert isinstance(da.isnull().data, dask_array_type) assert_equal(da.isnull().load(), da.load().isnull())

Output of xr.show_versions()

xarray master & dask 2.3.0

# Paste the output here xr.show_versions() here INSTALLED VERSIONS ------------------ commit: 6ece6a1cf424c3080e216fad8fc8058d3b70aadc python: 3.7.3 | packaged by conda-forge | (default, Jul 1 2019, 21:52:21) [GCC 7.3.0] python-bits: 64 OS: Linux OS-release: 4.15.0-64-generic machine: x86_64 processor: x86_64 byteorder: little LC_ALL: None LANG: en_US.UTF-8 LOCALE: en_US.UTF-8 libhdf5: 1.10.4 libnetcdf: 4.6.2 xarray: 0.13.0+13.g6ece6a1c pandas: 0.25.1 numpy: 1.17.2 scipy: 1.3.1 netCDF4: 1.5.1.2 pydap: None h5netcdf: 0.7.4 h5py: 2.9.0 Nio: None zarr: None cftime: 1.0.3.4 nc_time_axis: None PseudoNetCDF: None rasterio: None cfgrib: 0.9.7.1 iris: None bottleneck: 1.2.1 *dask: 2.3.0* distributed: 2.3.2 matplotlib: 3.1.1 cartopy: 0.17.0 seaborn: 0.9.0 numbagg: None setuptools: 41.2.0 pip: 19.2.3 conda: 4.7.11 pytest: 5.1.2 IPython: 7.8.0 sphinx: 2.2.0