Fix combine from zarr with parquet

kerchunk/combine.py

@@ -459,7 +459,10 @@ def second_pass(self):
                     # a coordinate is any array appearing in its own or other array's _ARRAY_DIMENSIONS
                     skip.add(v)
                     for k in fs.ls(v, detail=False):
-                        self.out[k] = fs.references[k]
+                        if k.rsplit("/", 1)[-1].startswith(".z"):
+                            self.out[k] = fs.cat(k)
+                        else:
+                            self.out[k] = fs.references[k]
                     continue
 
                 dont_skip.add(v)  # don't check for coord or identical again

kerchunk/tests/test_zarr.py

@@ -3,7 +3,9 @@
 import pandas as pd
 import pytest
 import xarray as xr
+import fsspec.implementations.reference as reffs
 
+import kerchunk.combine
 import kerchunk.zarr
 import kerchunk.utils
 
@@ -68,3 +70,17 @@ def test_zarr_in_zip(zarr_in_zip, ds):
         "reference", fo=out, remote_protocol="zip", remote_options={"fo": zarr_in_zip}
     )
     assert isinstance(fs.references["temp/.zarray"], (str, bytes))
+
+
+def test_zarr_combine(tmpdir, ds):
+    fn1 = f"{tmpdir}/test1.zarr"
+    ds.to_zarr(fn1)
+
+    one = kerchunk.zarr.ZarrToZarr(fn1, inline_threshold=0).translate()
+    fn = f"{tmpdir}/out.parq"
+    out = reffs.LazyReferenceMapper.create(fn)
+    mzz = kerchunk.combine.MultiZarrToZarr([one], concat_dims=["time"], out=out)
+    mzz.translate()
+
+    ds2 = xr.open_dataset(fn, engine="kerchunk")
+    assert ds.equals(ds2)