Raise ValueError for unmatching chunks length in DataArray.chunk() (

#9689)

* add `ValueError`

* add test

xarray/core/dataarray.py

@@ -1444,6 +1444,11 @@ def chunk(
                 "It will raise an error in the future. Instead use a dict with dimension names as keys.",
                 category=DeprecationWarning,
             )
+            if len(chunks) != len(self.dims):
+                raise ValueError(
+                    f"chunks must have the same number of elements as dimensions. "
+                    f"Expected {len(self.dims)} elements, got {len(chunks)}."
+                )
             chunk_mapping = dict(zip(self.dims, chunks, strict=True))
         else:
             chunk_mapping = either_dict_or_kwargs(chunks, chunks_kwargs, "chunk")

xarray/tests/test_dataarray.py

@@ -897,6 +897,9 @@ def test_chunk(self) -> None:
             assert blocked.chunks == ((3,), (3, 1))
             assert blocked.data.name != first_dask_name
 
+            with pytest.raises(ValueError):
+                blocked.chunk(chunks=(3, 3, 3))
+
         # name doesn't change when rechunking by same amount
         # this fails if ReprObject doesn't have __dask_tokenize__ defined
         assert unblocked.chunk(2).data.name == unblocked.chunk(2).data.name