refactor: bring in types from zarr-metadata

.pre-commit-config.yaml

@@ -42,6 +42,7 @@ repos:
           - typing_extensions
           - universal-pathlib
           - obstore>=0.5.1
+          - zarr-metadata>=0.1.1
           # Tests
           - pytest
           - hypothesis

pyproject.toml

@@ -38,6 +38,7 @@ dependencies = [
     'google-crc32c>=1.5',
     'typing_extensions>=4.13',
     'donfig>=0.8',
+    'zarr-metadata>=0.1.1',
 ]
 
 dynamic = [

src/zarr/codecs/blosc.py

@@ -9,10 +9,22 @@
 import numcodecs
 from numcodecs.blosc import Blosc
 from packaging.version import Version
+from zarr_metadata.v3.codec.blosc import (
+    BloscCName as _BloscCName,
+)
+from zarr_metadata.v3.codec.blosc import (
+    BloscCodecConfiguration as _BloscCodecConfiguration,
+)
+from zarr_metadata.v3.codec.blosc import (
+    BloscCodecObject as _BloscCodecObject,
+)
+from zarr_metadata.v3.codec.blosc import (
+    BloscShuffle as _BloscShuffle,
+)
 
 from zarr.abc.codec import BytesBytesCodec
 from zarr.core.buffer.cpu import as_numpy_array_wrapper
-from zarr.core.common import JSON, NamedRequiredConfig, parse_enum, parse_named_configuration
+from zarr.core.common import JSON, parse_enum, parse_named_configuration
 from zarr.core.dtype.common import HasItemSize
 
 if TYPE_CHECKING:
@@ -21,14 +33,14 @@
     from zarr.core.array_spec import ArraySpec
     from zarr.core.buffer import Buffer
 
-Shuffle = Literal["noshuffle", "shuffle", "bitshuffle"]
-"""The shuffle values permitted for the blosc codec"""
+# Re-export under zarr-python's historical names.
+Shuffle = _BloscShuffle
+CName = _BloscCName
+BloscConfigV3 = _BloscCodecConfiguration
+BloscJSON_V3 = _BloscCodecObject
 
 SHUFFLE: Final = ("noshuffle", "shuffle", "bitshuffle")
 
-CName = Literal["lz4", "lz4hc", "blosclz", "snappy", "zlib", "zstd"]
-"""The codec identifiers used in the blosc codec """
-
 
 class BloscConfigV2(TypedDict):
     """Configuration for the V2 Blosc codec"""
@@ -40,22 +52,6 @@ class BloscConfigV2(TypedDict):
     typesize: NotRequired[int]
 
 
-class BloscConfigV3(TypedDict):
-    """Configuration for the V3 Blosc codec"""
-
-    cname: CName
-    clevel: int
-    shuffle: Shuffle
-    blocksize: int
-    typesize: int
-
-
-class BloscJSON_V3(NamedRequiredConfig[Literal["blosc"], BloscConfigV3]):
-    """
-    The JSON form of the Blosc codec in Zarr V3.
-    """
-
-
 class BloscShuffle(Enum):
     """
     Enum for shuffle filter used by blosc.

src/zarr/codecs/cast_value.py

@@ -12,7 +12,7 @@
 
 from collections.abc import Mapping
 from dataclasses import dataclass, replace
-from typing import TYPE_CHECKING, Final, Literal, TypedDict, cast
+from typing import TYPE_CHECKING, Final, TypedDict, cast
 
 import numpy as np
 
@@ -23,6 +23,8 @@
 if TYPE_CHECKING:
     from typing import NotRequired, Self
 
+    from zarr_metadata.v3.codec.cast_value import OutOfRangeMode, RoundingMode
+
     from zarr.core.array_spec import ArraySpec
     from zarr.core.buffer import NDBuffer
     from zarr.core.dtype.wrapper import TBaseDType, TBaseScalar, ZDType
@@ -33,17 +35,6 @@ class ScalarMapJSON(TypedDict):
         decode: NotRequired[list[tuple[object, object]]]
 
 
-RoundingMode = Literal[
-    "nearest-even",
-    "towards-zero",
-    "towards-positive",
-    "towards-negative",
-    "nearest-away",
-]
-
-OutOfRangeMode = Literal["clamp", "wrap"]
-
-
 class ScalarMap(TypedDict, total=False):
     """
     The normalized, in-memory form of a scalar map.

src/zarr/core/metadata/v2.py

@@ -3,7 +3,7 @@
 import warnings
 from collections.abc import Iterable, Sequence
 from functools import cached_property
-from typing import TYPE_CHECKING, Any, TypedDict, cast
+from typing import TYPE_CHECKING, Any, cast
 
 from zarr.abc.metadata import Metadata
 from zarr.abc.numcodec import Numcodec, _is_numcodec
@@ -29,8 +29,11 @@
 from dataclasses import dataclass, field, fields, replace
 
 import numpy as np
+from zarr_metadata.v2.array import ArrayMetadataV2 as _ArrayMetadataV2
 
 from zarr.core.array_spec import ArrayConfig, ArraySpec
+
+# Re-export the v2 array metadata JSON shape under zarr-python's historical name.
 from zarr.core.chunk_key_encodings import parse_separator
 from zarr.core.common import (
     JSON,
@@ -42,18 +45,9 @@
 from zarr.core.config import config, parse_indexing_order
 from zarr.core.metadata.common import parse_attributes
 
-
-class ArrayV2MetadataDict(TypedDict):
-    """
-    A typed dictionary model for Zarr format 2 metadata.
-    """
-
-    zarr_format: Literal[2]
-    attributes: dict[str, JSON]
-
-
 # Union of acceptable types for v2 compressors
 type CompressorLikev2 = dict[str, JSON] | Numcodec | None
+ArrayV2MetadataDict = _ArrayMetadataV2
 
 
 @dataclass(frozen=True, kw_only=True)

src/zarr/core/metadata/v3.py

@@ -3,9 +3,10 @@
 import json
 from collections.abc import Iterable, Mapping, Sequence
 from dataclasses import dataclass, field, replace
-from typing import TYPE_CHECKING, Any, Final, Literal, NotRequired, TypeGuard, cast
+from typing import TYPE_CHECKING, Any, Final, Literal, TypeGuard, cast
 
 from typing_extensions import TypedDict
+from zarr_metadata.v3.array import ArrayMetadataV3, ExtensionFieldV3
 
 from zarr.abc.codec import ArrayArrayCodec, ArrayBytesCodec, BytesBytesCodec, Codec
 from zarr.abc.metadata import Metadata
@@ -139,14 +140,12 @@ def parse_storage_transformers(data: object) -> tuple[dict[str, JSON], ...]:
     )
 
 
-class AllowedExtraField(TypedDict, extra_items=JSON):  # type: ignore[call-arg]
-    """
-    This class models allowed extra fields in array metadata.
-    They must have ``must_understand`` set to ``False``, and may contain
-    arbitrary additional JSON data.
-    """
+AllowedExtraField = ExtensionFieldV3
+"""Alias for `zarr_metadata.v3.array.ExtensionFieldV3`.
 
-    must_understand: Literal[False]
+`must_understand` is typed as `bool` to match the spec (extension authors that
+*understand* a field may produce `True`); the runtime guard
+`check_allowed_extra_field` enforces that zarr-python only accepts `False`."""
 
 
 def check_allowed_extra_field(data: object) -> TypeGuard[AllowedExtraField]:
@@ -421,25 +420,12 @@ def parse_chunk_grid(
     raise ValueError(f"Unknown chunk grid name: {name!r}")
 
 
-class ArrayMetadataJSON_V3(TypedDict, extra_items=AllowedExtraField):  # type: ignore[call-arg]
-    """
-    A typed dictionary model for zarr v3 array metadata.
-
-    Extra keys are permitted if they conform to ``AllowedExtraField``
-    (i.e. they are mappings with ``must_understand: false``).
-    """
+ArrayMetadataJSON_V3 = ArrayMetadataV3
+"""Alias for `zarr_metadata.v3.array.ArrayMetadataV3`.
 
-    zarr_format: Literal[3]
-    node_type: Literal["array"]
-    data_type: str | NamedConfig[str, Mapping[str, JSON]]
-    shape: tuple[int, ...]
-    chunk_grid: str | NamedConfig[str, Mapping[str, JSON]]
-    chunk_key_encoding: str | NamedConfig[str, Mapping[str, JSON]]
-    fill_value: JSON
-    codecs: tuple[str | NamedConfig[str, Mapping[str, JSON]], ...]
-    attributes: NotRequired[Mapping[str, JSON]]
-    storage_transformers: NotRequired[tuple[str | NamedConfig[str, Mapping[str, JSON]], ...]]
-    dimension_names: NotRequired[tuple[str | None, ...]]
+The TypedDict from the metadata package is the canonical model of the v3
+array metadata document; this alias preserves the historical zarr-python
+name. Extra keys are permitted if they conform to `ExtensionFieldV3`."""
 
 
 """
@@ -671,6 +657,12 @@ def from_dict(cls, data: dict[str, JSON]) -> Self:
         )
 
     def to_dict(self) -> dict[str, JSON]:
+        """Serialize as a JSON-shaped dict matching `ArrayMetadataV3`.
+
+        Return type is `dict[str, JSON]` rather than `ArrayMetadataV3` so the
+        result composes with other zarr-python metadata serialisation paths
+        that traffic in `dict[str, JSON]` (notably consolidated metadata).
+        """
         out_dict = super().to_dict()
         extra_fields = out_dict.pop("extra_fields")
         out_dict = out_dict | extra_fields  # type: ignore[operator]