zarr-developers · Carreau · Sep 19, 2020 · Feb 27, 2021 · Feb 27, 2021 · Feb 27, 2021
diff --git a/docs/tutorial.rst b/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

diff --git a/mypy.ini b/mypy.ini
@@ -1,4 +1,4 @@
 [mypy]
-python_version = 3.6
+python_version = 3.8
 ignore_missing_imports = True
 follow_imports = silent
diff --git a/pytest.ini b/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
diff --git a/zarr/convenience.py b/zarr/convenience.py
@@ -12,17 +12,21 @@
 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
 
+from typing import Union
+
+StoreLike = Union[Store, str, None]
+
 
 # noinspection PyShadowingBuiltins
-def open(store=None, mode='a', **kwargs):
+def open(store: StoreLike = None, mode: str = "a", **kwargs):
     """Convenience function to open a group or array using file-mode-like semantics.
 
     Parameters
     ----------
-    store : MutableMapping or string, optional
+    store : Store or string, optional
         Store or path to directory in file system or name of zip file.
     mode : {'r', 'r+', 'a', 'w', 'w-'}, optional
         Persistence mode: 'r' means read only (must exist); 'r+' means
@@ -75,32 +79,33 @@ def open(store=None, mode='a', **kwargs):
     clobber = mode == 'w'
     # we pass storage options explicitly, since normalize_store_arg might construct
     # a store if the input is a fsspec-compatible URL
-    store = normalize_store_arg(store, clobber=clobber,
-                                storage_options=kwargs.pop("storage_options", {}))
+    _store: Store = normalize_store_arg(
+        store, clobber=clobber, storage_options=kwargs.pop("storage_options", {})
+    )
     path = normalize_storage_path(path)
 
     if mode in {'w', 'w-', 'x'}:
         if 'shape' in kwargs:
-            return open_array(store, mode=mode, **kwargs)
+            return open_array(_store, mode=mode, **kwargs)
         else:
-            return open_group(store, mode=mode, **kwargs)
+            return open_group(_store, mode=mode, **kwargs)
 
     elif mode == "a":
-        if "shape" in kwargs or contains_array(store, path):
-            return open_array(store, mode=mode, **kwargs)
+        if "shape" in kwargs or contains_array(_store, path):
+            return open_array(_store, mode=mode, **kwargs)
         else:
-            return open_group(store, mode=mode, **kwargs)
+            return open_group(_store, mode=mode, **kwargs)
 
     else:
-        if contains_array(store, path):
-            return open_array(store, mode=mode, **kwargs)
-        elif contains_group(store, path):
-            return open_group(store, mode=mode, **kwargs)
+        if contains_array(_store, path):
+            return open_array(_store, mode=mode, **kwargs)
+        elif contains_group(_store, path):
+            return open_group(_store, mode=mode, **kwargs)
         else:
             raise PathNotFoundError(path)
 
 
-def save_array(store, arr, **kwargs):
+def save_array(store: StoreLike, arr, **kwargs):
     """Convenience function to save a NumPy array to the local file system, following a
     similar API to the NumPy save() function.
 
@@ -132,16 +137,16 @@ def save_array(store, arr, **kwargs):
 
     """
     may_need_closing = isinstance(store, str)
-    store = normalize_store_arg(store, clobber=True)
+    _store: Store = normalize_store_arg(store, clobber=True)
     try:
-        _create_array(arr, store=store, overwrite=True, **kwargs)
+        _create_array(arr, store=_store, overwrite=True, **kwargs)
     finally:
-        if may_need_closing and hasattr(store, 'close'):
+        if may_need_closing:
             # needed to ensure zip file records are written
-            store.close()
+            _store.close()
 
 
-def save_group(store, *args, **kwargs):
+def save_group(store: StoreLike, *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.
 
@@ -203,21 +208,21 @@ def save_group(store, *args, **kwargs):
         raise ValueError('at least one array must be provided')
     # handle polymorphic store arg
     may_need_closing = isinstance(store, str)
-    store = normalize_store_arg(store, clobber=True)
+    _store: Store = normalize_store_arg(store, clobber=True)
     try:
-        grp = _create_group(store, overwrite=True)
+        grp = _create_group(_store, overwrite=True)
         for i, arr in enumerate(args):
             k = 'arr_{}'.format(i)
             grp.create_dataset(k, data=arr, overwrite=True)
         for k, arr in kwargs.items():
             grp.create_dataset(k, data=arr, overwrite=True)
     finally:
-        if may_need_closing and hasattr(store, 'close'):
+        if may_need_closing:
             # needed to ensure zip file records are written
-            store.close()
+            _store.close()
 
 
-def save(store, *args, **kwargs):
+def save(store: StoreLike, *args, **kwargs):
    """Convenience function to save an array or group of arrays to the local file system.
 
     Parameters
@@ -327,7 +332,7 @@ def __repr__(self):
         return r
 
 
-def load(store):
+def load(store: StoreLike):
     """Load data from an array or group into memory.
 
     Parameters
@@ -353,11 +358,11 @@ def load(store):
 
     """
     # handle polymorphic store arg
-    store = normalize_store_arg(store)
-    if contains_array(store, path=None):
-        return Array(store=store, path=None)[...]
-    elif contains_group(store, path=None):
-        grp = Group(store=store, path=None)
+    _store = normalize_store_arg(store)
+    if contains_array(_store, path=None):
+        return Array(store=_store, path=None)[...]
+    elif contains_group(_store, path=None):
+        grp = Group(store=_store, path=None)
         return LazyLoader(grp)
 
 
@@ -1073,7 +1078,7 @@ 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.
@@ -1124,7 +1129,7 @@ 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

diff --git a/zarr/core.py b/zarr/core.py
@@ -9,6 +9,8 @@
 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, ArrayIndexError
@@ -29,7 +31,7 @@
     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.storage import array_meta_key, attrs_key, getsize, listdir, Store
 from zarr.util import (
     InfoReporter,
     check_array_shape,
@@ -129,7 +131,7 @@ class Array:
 
     def __init__(
         self,
-        store,
+        store: Store,
         path=None,
         read_only=False,
         chunk_store=None,
@@ -141,6 +143,9 @@ def __init__(
         # 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)
@@ -2009,7 +2014,7 @@ 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
@@ -2042,10 +2047,10 @@ 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
 
         """

diff --git a/zarr/creation.py b/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 +139,9 @@ def create(shape, chunks=True, dtype=None, compressor='default',
     return z
 
 
-def normalize_store_arg(store, clobber=False, storage_options=None, mode='w'):
+def normalize_store_arg(store, clobber=False, storage_options=None, mode="w") -> Store:
     if store is None:
-        return dict()
+        return Store._ensure_store(dict())
     elif isinstance(store, str):
         mode = mode if clobber else "r"
         if "://" in store or "::" in store:
@@ -145,6 +155,8 @@ def normalize_store_arg(store, clobber=False, storage_options=None, mode='w'):
         else:
             return DirectoryStore(store)
     else:
+        if not isinstance(store, Store) and isinstance(store, MutableMapping):
+            store = KVStore(store)
         return store