Introduce a base store Class

Unconditionally close store in tests.

All the tested stores should now have a `close()` method we can call and
will be no-op if the stores do not need closing.

Turn UserWarnings into errors

And turn then back into only warnings into relevant tests.
This ensure that we are not using deprecated functionalities, except
when testing for it.

initially based on 318eddcd, and later 1249f35

docs/tutorial.rst

@@ -176,7 +176,7 @@ print some diagnostics, e.g.::
     Read-only          : False
     Compressor         : Blosc(cname='zstd', clevel=3, shuffle=BITSHUFFLE,
                        : blocksize=0)
-    Store type         : builtins.dict
+    Store type         : zarr.storage.KVStore
     No. bytes          : 400000000 (381.5M)
     No. bytes stored   : 3379344 (3.2M)
     Storage ratio      : 118.4
@@ -268,7 +268,7 @@ Here is an example using a delta filter with the Blosc compressor::
     Read-only          : False
     Filter [0]         : Delta(dtype='<i4')
     Compressor         : Blosc(cname='zstd', clevel=1, shuffle=SHUFFLE, blocksize=0)
-    Store type         : builtins.dict
+    Store type         : zarr.storage.KVStore
     No. bytes          : 400000000 (381.5M)
     No. bytes stored   : 1290562 (1.2M)
     Storage ratio      : 309.9
@@ -795,8 +795,10 @@ Here is an example using S3Map to read an array created previously::
     Order              : C
     Read-only          : False
     Compressor         : Blosc(cname='lz4', clevel=5, shuffle=SHUFFLE, blocksize=0)
-    Store type         : fsspec.mapping.FSMap
+    Store type         : zarr.storage.KVStore
     No. bytes          : 21
+    No. bytes stored   : 382
+    Storage ratio      : 0.1
     Chunks initialized : 3/3
     >>> z[:]
     array([b'H', b'e', b'l', b'l', b'o', b' ', b'f', b'r', b'o', b'm', b' ',
@@ -1262,7 +1264,7 @@ ratios, depending on the correlation structure within the data. E.g.::
     Order              : C
     Read-only          : False
     Compressor         : Blosc(cname='lz4', clevel=5, shuffle=SHUFFLE, blocksize=0)
-    Store type         : builtins.dict
+    Store type         : zarr.storage.KVStore
     No. bytes          : 400000000 (381.5M)
     No. bytes stored   : 6696010 (6.4M)
     Storage ratio      : 59.7
@@ -1276,7 +1278,7 @@ ratios, depending on the correlation structure within the data. E.g.::
     Order              : F
     Read-only          : False
     Compressor         : Blosc(cname='lz4', clevel=5, shuffle=SHUFFLE, blocksize=0)
-    Store type         : builtins.dict
+    Store type         : zarr.storage.KVStore
     No. bytes          : 400000000 (381.5M)
     No. bytes stored   : 4684636 (4.5M)
     Storage ratio      : 85.4

mypy.ini

@@ -1,4 +1,4 @@
 [mypy]
-python_version = 3.6
+python_version = 3.8
 ignore_missing_imports = True
 follow_imports = silent

pytest.ini

@@ -3,4 +3,6 @@ doctest_optionflags = NORMALIZE_WHITESPACE ELLIPSIS IGNORE_EXCEPTION_DETAIL
 addopts = --durations=10
 filterwarnings =
     error::DeprecationWarning:zarr.*
+    error::UserWarning:zarr.*
     ignore:PY_SSIZE_T_CLEAN will be required.*:DeprecationWarning
+    ignore:The loop argument is deprecated since Python 3.8.*:DeprecationWarning

zarr/convenience.py

@@ -12,7 +12,7 @@
 from zarr.hierarchy import group as _create_group
 from zarr.hierarchy import open_group
 from zarr.meta import json_dumps, json_loads
-from zarr.storage import contains_array, contains_group
+from zarr.storage import contains_array, contains_group, Store
 from zarr.util import TreeViewer, buffer_size, normalize_storage_path
 
 
@@ -73,7 +73,7 @@ def open(store=None, mode='a', **kwargs):
     path = kwargs.get('path', None)
     # handle polymorphic store arg
     clobber = mode == 'w'
-    store = normalize_store_arg(store, clobber=clobber)
+    store: Store = normalize_store_arg(store, clobber=clobber)
     path = normalize_storage_path(path)
 
     if mode in {'w', 'w-', 'x'}:
@@ -97,7 +97,7 @@ def open(store=None, mode='a', **kwargs):
             raise PathNotFoundError(path)
 
 
-def save_array(store, arr, **kwargs):
+def save_array(store: Store, arr, **kwargs):
     """Convenience function to save a NumPy array to the local file system, following a
     similar API to the NumPy save() function.
 
@@ -138,7 +138,7 @@ def save_array(store, arr, **kwargs):
             store.close()
 
 
-def save_group(store, *args, **kwargs):
+def save_group(store: Store, *args, **kwargs):
     """Convenience function to save several NumPy arrays to the local file system, following a
     similar API to the NumPy savez()/savez_compressed() functions.
 
@@ -214,7 +214,7 @@ def save_group(store, *args, **kwargs):
             store.close()
 
 
-def save(store, *args, **kwargs):
+def save(store: Store, *args, **kwargs):
     """Convenience function to save an array or group of arrays to the local file system.
 
     Parameters
@@ -324,7 +324,7 @@ def __repr__(self):
         return r
 
 
-def load(store):
+def load(store: Store):
     """Load data from an array or group into memory.
 
     Parameters
@@ -1069,7 +1069,7 @@ def copy_all(source, dest, shallow=False, without_attrs=False, log=None,
     return n_copied, n_skipped, n_bytes_copied
 
 
-def consolidate_metadata(store, metadata_key='.zmetadata'):
+def consolidate_metadata(store: Store, metadata_key=".zmetadata"):
     """
     Consolidate all metadata for groups and arrays within the given store
     into a single resource and put it under the given key.
@@ -1120,7 +1120,7 @@ def is_zarr_key(key):
     return open_consolidated(store, metadata_key=metadata_key)
 
 
-def open_consolidated(store, metadata_key='.zmetadata', mode='r+', **kwargs):
+def open_consolidated(store: Store, metadata_key=".zmetadata", mode="r+", **kwargs):
     """Open group using metadata previously consolidated into a single key.
 
     This is an optimised method for opening a Zarr group, where instead of

zarr/core.py

@@ -9,20 +9,39 @@
 import numpy as np
 from numcodecs.compat import ensure_bytes, ensure_ndarray
 
+from collections.abc import MutableMapping
+
 from zarr.attrs import Attributes
 from zarr.codecs import AsType, get_codec
 from zarr.errors import ArrayNotFoundError, ReadOnlyError
-from zarr.indexing import (BasicIndexer, CoordinateIndexer, MaskIndexer,
-                           OIndex, OrthogonalIndexer, VIndex, check_fields,
-                           check_no_multi_fields, ensure_tuple,
-                           err_too_many_indices, is_contiguous_selection,
-                           is_scalar, pop_fields)
+from zarr.indexing import (
+    BasicIndexer,
+    CoordinateIndexer,
+    MaskIndexer,
+    OIndex,
+    OrthogonalIndexer,
+    VIndex,
+    check_fields,
+    check_no_multi_fields,
+    ensure_tuple,
+    err_too_many_indices,
+    is_contiguous_selection,
+    is_scalar,
+    pop_fields,
+)
 from zarr.meta import decode_array_metadata, encode_array_metadata
-from zarr.storage import array_meta_key, attrs_key, getsize, listdir
-from zarr.util import (InfoReporter, check_array_shape, human_readable_size,
-                       is_total_slice, nolock, normalize_chunks,
-                       normalize_resize_args, normalize_shape,
-                       normalize_storage_path)
+from zarr.storage import array_meta_key, attrs_key, getsize, listdir, Store
+from zarr.util import (
+    InfoReporter,
+    check_array_shape,
+    human_readable_size,
+    is_total_slice,
+    nolock,
+    normalize_chunks,
+    normalize_resize_args,
+    normalize_shape,
+    normalize_storage_path,
+)
 
 
 # noinspection PyUnresolvedReferences
@@ -107,6 +126,9 @@ def __init__(self, store, path=None, read_only=False, chunk_store=None,
         # N.B., expect at this point store is fully initialized with all
         # configuration metadata fully specified and normalized
 
+        store = Store._ensure_store(store)
+        chunk_store = Store._ensure_store(chunk_store)
+
         self._store = store
         self._chunk_store = chunk_store
         self._path = normalize_storage_path(path)
@@ -1851,7 +1873,7 @@ def _encode_chunk(self, chunk):
             cdata = chunk
 
         # ensure in-memory data is immutable and easy to compare
-        if isinstance(self.chunk_store, dict):
+        if isinstance(self.chunk_store, MutableMapping):
             cdata = ensure_bytes(cdata)
 
         return cdata
@@ -1884,10 +1906,10 @@ def info(self):
         Order              : C
         Read-only          : False
         Compressor         : Blosc(cname='lz4', clevel=5, shuffle=SHUFFLE, blocksize=0)
-        Store type         : builtins.dict
+        Store type         : zarr.storage.KVStore
         No. bytes          : 4000000 (3.8M)
-        No. bytes stored   : ...
-        Storage ratio      : ...
+        No. bytes stored   : 320
+        Storage ratio      : 12500.0
         Chunks initialized : 0/10
 
         """

zarr/creation.py

@@ -2,6 +2,7 @@
 
 import numpy as np
 from numcodecs.registry import codec_registry
+from collections.abc import MutableMapping
 
 from zarr.core import Array
 from zarr.errors import (
@@ -10,9 +11,18 @@
     ContainsGroupError,
 )
 from zarr.n5 import N5Store
-from zarr.storage import (DirectoryStore, ZipStore, contains_array,
-                          contains_group, default_compressor, init_array,
-                          normalize_storage_path, FSStore)
+from zarr.storage import (
+    DirectoryStore,
+    ZipStore,
+    KVStore,
+    contains_array,
+    contains_group,
+    default_compressor,
+    init_array,
+    normalize_storage_path,
+    FSStore,
+    Store,
+)
 
 
 def create(shape, chunks=True, dtype=None, compressor='default',
@@ -129,9 +139,11 @@ def create(shape, chunks=True, dtype=None, compressor='default',
     return z
 
 
-def normalize_store_arg(store, clobber=False, default=dict, storage_options=None):
+def normalize_store_arg(
+    store, clobber=False, default=dict, storage_options=None
+) -> Store:
     if store is None:
-        return default()
+        return Store._ensure_store(default())
     elif isinstance(store, str):
         mode = 'w' if clobber else 'r'
         if "://" in store or "::" in store:
@@ -145,6 +157,8 @@ def normalize_store_arg(store, clobber=False, default=dict, storage_options=None
         else:
             return DirectoryStore(store)
     else:
+        if not isinstance(store, Store) and isinstance(store, MutableMapping):
+            store = KVStore(store)
         return store
 
 

zarr/hierarchy.py

@@ -15,11 +15,26 @@
     ReadOnlyError,
 )
 from zarr.meta import decode_group_metadata
-from zarr.storage import (MemoryStore, attrs_key, contains_array,
-                          contains_group, group_meta_key, init_group, listdir,
-                          rename, rmdir)
-from zarr.util import (InfoReporter, TreeViewer, is_valid_python_name, nolock,
-                       normalize_shape, normalize_storage_path)
+from zarr.storage import (
+    MemoryStore,
+    attrs_key,
+    contains_array,
+    contains_group,
+    group_meta_key,
+    init_group,
+    listdir,
+    rename,
+    rmdir,
+    Store,
+)
+from zarr.util import (
+    InfoReporter,
+    TreeViewer,
+    is_valid_python_name,
+    nolock,
+    normalize_shape,
+    normalize_storage_path,
+)
 
 
 class Group(MutableMapping):
@@ -96,6 +111,8 @@ class Group(MutableMapping):
 
     def __init__(self, store, path=None, read_only=False, chunk_store=None,
                  cache_attrs=True, synchronizer=None):
+        store = Store._ensure_store(store)
+        chunk_store = Store._ensure_store(chunk_store)
         self._store = store
         self._chunk_store = chunk_store
         self._path = normalize_storage_path(path)
@@ -237,11 +254,8 @@ def __enter__(self):
         return self
 
     def __exit__(self, exc_type, exc_val, exc_tb):
-        """If the underlying Store has a ``close`` method, call it."""
-        try:
-            self.store.close()
-        except AttributeError:
-            pass
+        """If the underlying Store should always heave a ``close`` method, call it."""
+        self.store.close()
 
     def info_items(self):
 
@@ -1036,7 +1050,7 @@ def move(self, source, dest):
 
 
 def _normalize_store_arg(store, clobber=False, storage_options=None):
-    return normalize_store_arg(store, clobber=clobber, default=MemoryStore,
+    return normalize_store_arg(store, clobber=clobber, default=MemoryStore,	    return normalize_store_arg(
                                storage_options=storage_options)