issue_comments: 498072960

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https://github.com/pydata/xarray/pull/2706#issuecomment-498072960 https://api.github.com/repos/pydata/xarray/issues/2706 498072960 MDEyOklzc3VlQ29tbWVudDQ5ODA3Mjk2MA== 8643775 2019-06-02T23:07:41Z 2019-06-02T23:07:41Z NONE

Hi all, not sure if I could be doing something wrong myself, but the below might be a bug in this PR.

I checked out the jendrik_joe:append_zarr branch. When calling to_zarr on a Dataset with the compute=False argument, the data array should not be populated in the target zarr store right? But it seems to be doing just that(I though only metadata should be initialised). ```python

import zarr import xarray ds = xarray.Dataset( ... {'arr1': (['dim1', 'dim2'], [[10,11],[12,13]])}, ... coords={'dim1': [1, 2], 'dim2': [1,2]} ... ) store = dict() ds = ds.chunk(dict(dim1=1, dim2=1)) ds <xarray.Dataset> Dimensions: (dim1: 2, dim2: 2) Coordinates: * dim1 (dim1) int64 1 2 * dim2 (dim2) int64 1 2 Data variables: arr1 (dim1, dim2) int64 dask.array<shape=(2, 2), chunksize=(1, 1)> store = dict() ds.to_zarr(store, mode='w', compute=False) Delayed('_finalize_store-72c3ec95-6ef1-473a-a0de-e81c98eb9576') xarray.open_zarr(store)['arr1'].values array([[10, 11], [12, 13]]) ```

Instead this does not happen in the xarray master branch: ```python

import zarr import xarray ds = xarray.Dataset( ... {'arr1': (['dim1', 'dim2'], [[10,11],[12,13]])}, ... coords={'dim1': [1, 2], 'dim2': [1,2]} ... ) ds = ds.chunk(dict(dim1=1, dim2=1)) ds <xarray.Dataset> Dimensions: (dim1: 2, dim2: 2) Coordinates: * dim1 (dim1) int64 1 2 * dim2 (dim2) int64 1 2 Data variables: arr1 (dim1, dim2) int64 dask.array<shape=(2, 2), chunksize=(1, 1)> store = dict() ds.to_zarr(store, mode='w', compute=False) Delayed('_finalize_store-965b0a89-bff6-4adc-8bab-e47a77e762f3') xarray.open_zarr(store)['arr1'].values array([[4611686018427387904, 4611686018427387904], [4611686018427387904, 4611686018427387904]]) Python: 3.6.7python xarray.version '0.12.1+45.g519b3986' zarr.version '2.2.1.dev185'

OS: Distributor ID: Ubuntu Description: Ubuntu 18.04.2 LTS Release: 18.04 Codename: bionic ```

I am also trying to figure out why this is happening(assuming this is a bug) and will post updates soon.

@davidbrochart 

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