Try to converge on internal types consistency.

docs/release.rst

@@ -5,6 +5,11 @@ Release notes
 Next release
 ------------
 
+* For consistency across stores, the `ConsolidatedMetadataStore` will return
+  bytes instead of objects for metadata. Internally zarr tries to be more type
+  stable and attempt to always pass bytes-likes object when storing objects on
+  stores.
+
 * Fix minor bug in `N5Store`. 
   By :user:`gsakkis`, :issue:`550`.
 

zarr/core.py

@@ -1489,7 +1489,7 @@ def _set_basic_selection_zd(self, selection, value, fields=None):
             chunk[selection] = value
 
         # encode and store
-        cdata = self._encode_chunk(chunk)
+        cdata = ensure_bytes(self._encode_chunk(chunk))
         self.chunk_store[ckey] = cdata
 
     def _set_basic_selection_nd(self, selection, value, fields=None):

zarr/storage.py

@@ -44,7 +44,7 @@
 from zarr.meta import encode_array_metadata, encode_group_metadata
 from zarr.util import (buffer_size, json_loads, nolock, normalize_chunks,
                        normalize_dtype, normalize_fill_value, normalize_order,
-                       normalize_shape, normalize_storage_path)
+                       normalize_shape, normalize_storage_path, json_dumps)
 
 __doctest_requires__ = {
     ('RedisStore', 'RedisStore.*'): ['redis'],
@@ -2479,6 +2479,10 @@ class ConsolidatedMetadataStore(MutableMapping):
 
     .. versionadded:: 2.3
 
+    .. versionchanged:: 2.5
+
+        __getitem__ will now return bytes for metadata for consistency across stores.
+
     .. note:: This is an experimental feature.
 
     Parameters
@@ -2507,7 +2511,9 @@ def __init__(self, store, metadata_key='.zmetadata'):
                                 consolidated_format)
 
         # decode metadata
-        self.meta_store = meta['metadata']
+        self.meta_store = {}
+        for k, v in meta["metadata"].items():
+            self.meta_store[k] = json_dumps(v)
 
     def __getitem__(self, key):
         return self.meta_store[key]

zarr/tests/test_convenience.py

@@ -697,12 +697,6 @@ def test_logging(self):
             copy(source['foo'], dest, dry_run=True, log=True)
 
 
-try:
-    import h5py
-except ImportError:  # pragma: no cover
-    h5py = None
-
-
 def temp_h5f():
     h5py = pytest.importorskip("h5py")
     fn = tempfile.mktemp()

zarr/tests/test_meta.py

@@ -424,15 +424,15 @@ def test_encode_decode_dtype():
 def test_decode_group():
 
     # typical
-    b = '''{
+    b = b'''{
         "zarr_format": %s
-    }''' % ZARR_FORMAT
+    }''' % str(ZARR_FORMAT).encode()
     meta = decode_group_metadata(b)
     assert ZARR_FORMAT == meta['zarr_format']
 
     # unsupported format
-    b = '''{
+    b = b'''{
         "zarr_format": %s
-    }''' % (ZARR_FORMAT - 1)
+    }''' % str(ZARR_FORMAT - 1).encode()
     with pytest.raises(MetadataError):
         decode_group_metadata(b)

zarr/tests/test_storage.py

@@ -30,6 +30,7 @@
                           attrs_key, default_compressor, getsize,
                           group_meta_key, init_array, init_group, migrate_1to2)
 from zarr.tests.util import CountingDict, skip_test_env_var
+from zarr.util import json_dumps
 
 
 @contextmanager
@@ -1627,11 +1628,26 @@ def test_read_write(self):
         # setup store with consolidated metdata
         store = dict()
         consolidated = {
-            'zarr_consolidated_format': 1,
-            'metadata': {
-                'foo': 'bar',
-                'baz': 42,
-            }
+            "zarr_consolidated_format": 1,
+            "metadata": {
+                ".zgroup": {"zarr_format": 2},
+                "g2/arr/.zarray": {
+                    "chunks": [5, 5],
+                    "compressor": {
+                        "blocksize": 0,
+                        "clevel": 5,
+                        "cname": "lz4",
+                        "id": "blosc",
+                        "shuffle": 1,
+                    },
+                    "dtype": "<f8",
+                    "fill_value": 0.0,
+                    "filters": None,
+                    "order": "C",
+                    "shape": [20, 20],
+                    "zarr_format": 2,
+                },
+            },
         }
         store['.zmetadata'] = json.dumps(consolidated).encode()
 
@@ -1641,7 +1657,7 @@ def test_read_write(self):
         # test __contains__, __getitem__
         for key, value in consolidated['metadata'].items():
             assert key in cs
-            assert value == cs[key]
+            assert json_dumps(value) == cs[key]
 
         # test __delitem__, __setitem__
         with pytest.raises(PermissionError):