Updates for Zarr 3 Dtypes

.github/workflows/upstream-dev-ci.yaml

@@ -23,8 +23,7 @@ jobs:
     name: detect upstream-dev ci trigger
     runs-on: ubuntu-latest
     if: |
-      github.repository == 'pydata/xarray'
-      && (github.event_name == 'push' || github.event_name == 'pull_request')
+      github.event_name == 'push' || github.event_name == 'pull_request'
     outputs:
       triggered: ${{ steps.detect-trigger.outputs.trigger-found }}
     steps:

xarray/backends/zarr.py

@@ -816,11 +816,29 @@ def open_store_variable(self, name):
             if zarr_array.fill_value is not None:
                 attributes["_FillValue"] = zarr_array.fill_value
         elif "_FillValue" in attributes:
-            attributes["_FillValue"] = FillValueCoder.decode(
-                attributes["_FillValue"], zarr_array.dtype
-            )
+            # TODO update version check for the released version with dtypes
+            #  probably be 3.1
+
+            # if Version(zarr.__version__) > Version("3.0.10"):
+            if hasattr(zarr_array.metadata.data_type, "to_native_dtype"):
+                native_dtype = zarr_array.metadata.data_type.to_native_dtype()
+                attributes["_FillValue"] = (
+                    # Use the new dtype infrastructure instead of doing xarray
+                    # specific fill value decoding
+                    FillValueCoder.decode(
+                        attributes["_FillValue"],
+                        native_dtype,
+                    )
+                )
+            else:
+                dtype_value = zarr_array.metadata.data_type.value
+                attributes["_FillValue"] = FillValueCoder.decode(
+                    attributes["_FillValue"], dtype_value
+                )
+
+        variable = Variable(dimensions, data, attributes, encoding)
 
-        return Variable(dimensions, data, attributes, encoding)
+        return variable
 
     def get_variables(self):
         return FrozenDict((k, self.open_store_variable(k)) for k in self.array_keys())

xarray/tests/__init__.py

@@ -130,6 +130,20 @@ def _importorskip(
 has_rasterio, requires_rasterio = _importorskip("rasterio")
 has_zarr, requires_zarr = _importorskip("zarr")
 has_zarr_v3, requires_zarr_v3 = _importorskip("zarr", "3.0.0")
+has_zarr_v3_dtypes, requires_zarr_v3_dtypes = _importorskip("zarr", "3.0.10")
+if has_zarr_v3:
+    import zarr
+
+    # manual update by checking attrs for now
+    # TODO: use version specifier
+    # installing from git main is giving me a lower version than the
+    # most recently released zarr
+    has_zarr_v3_dtypes = hasattr(zarr.core, "dtype")
+
+    requires_zarr_v3_dtypes = pytest.mark.skipif(
+        not has_zarr_v3_dtypes, reason="requires zarr>3.0.10 (including dev versions)"
+    )
+
 has_fsspec, requires_fsspec = _importorskip("fsspec")
 has_iris, requires_iris = _importorskip("iris")
 has_numbagg, requires_numbagg = _importorskip("numbagg")

xarray/tests/test_backends.py

@@ -72,6 +72,7 @@
     has_scipy,
     has_zarr,
     has_zarr_v3,
+    has_zarr_v3_dtypes,
     mock,
     network,
     requires_cftime,
@@ -2416,7 +2417,7 @@ def test_read_non_consolidated_warning(self) -> None:
     def test_non_existent_store(self) -> None:
         with pytest.raises(
             FileNotFoundError,
-            match="(No such file or directory|Unable to find group|No group found)",
+            match="(No such file or directory|Unable to find group|No group found in store)",
         ):
             xr.open_zarr(f"{uuid.uuid4()}")
 
@@ -2498,6 +2499,7 @@ def test_manual_chunk(self) -> None:
                 assert_identical(actual.load(), auto.load())
 
     @requires_dask
+    @pytest.mark.filterwarnings("ignore:.*does not have a Zarr V3 specification.*")
     def test_warning_on_bad_chunks(self) -> None:
         original = create_test_data().chunk({"dim1": 4, "dim2": 3, "dim3": 3})
 
@@ -2906,7 +2908,9 @@ def test_append_with_existing_encoding_raises(self) -> None:
 
     @pytest.mark.parametrize("dtype", ["U", "S"])
     def test_append_string_length_mismatch_raises(self, dtype) -> None:
-        skip_if_zarr_format_3("This actually works fine with Zarr format 3")
+        if has_zarr_v3 and not has_zarr_v3_dtypes:
+            skip_if_zarr_format_3("This actually works fine with Zarr format 3")
+
         ds, ds_to_append = create_append_string_length_mismatch_test_data(dtype)
         with self.create_zarr_target() as store_target:
             ds.to_zarr(store_target, mode="w", **self.version_kwargs)
@@ -2919,8 +2923,12 @@ def test_append_string_length_mismatch_raises(self, dtype) -> None:
     def test_append_string_length_mismatch_works(self, dtype) -> None:
         skip_if_zarr_format_2("This doesn't work with Zarr format 2")
         # ...but it probably would if we used object dtype
+        if has_zarr_v3_dtypes:
+            pytest.skip("This works on pre ZDtype Zarr-Python, but fails after.")
+
         ds, ds_to_append = create_append_string_length_mismatch_test_data(dtype)
         expected = xr.concat([ds, ds_to_append], dim="time")
+
         with self.create_zarr_target() as store_target:
             ds.to_zarr(store_target, mode="w", **self.version_kwargs)
             ds_to_append.to_zarr(store_target, append_dim="time", **self.version_kwargs)