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da.to_zarr 2026.1.2 not backwards compatible with dask<2025.12.0 with zarr_format keyword arg and component #12265

@joshua-gould

Description

@joshua-gould
import dask.array as da

# Group.create_array() got an unexpected keyword argument 'zarr_format'
# works with dask<2025.12.0
# fails with 2026.1.2
da.to_zarr(
    arr=da.random.random((2, 2)),
    url="test1.zarr",
    zarr_format=2,
    component="0",
)

# works with dask<2025.12.0 and 2026.1.2
da.to_zarr(
    arr=da.random.random((2, 2)),
    url="test2.zarr",
    zarr_format=2,
)

Environment:

  • Dask version: 2026.1.2
  • Install method: pip

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