Fix: allow "bytes" as an alias for "variable_length_bytes" (#3532)

* add bytes alias for VariableLengthBytes

* make alias test stand-alone

* changelog

Author: d-v-b

changes/3532.misc.md

@@ -0,0 +1,2 @@
+Accept `"bytes"` as an alias for `"variable_length_bytes"` when parsing `JSON`-encoded Zarr V3
+data types.

src/zarr/core/dtype/npy/bytes.py

@@ -1046,7 +1046,7 @@ def _check_json_v3(cls, data: DTypeJSON) -> TypeGuard[Literal["variable_length_b
             True if the input is a valid representation of this class in Zarr V3, False otherwise.
         """
 
-        return data == cls._zarr_v3_name
+        return data in (cls._zarr_v3_name, "bytes")
 
     @classmethod
     def _from_json_v2(cls, data: DTypeJSON) -> Self:

tests/test_dtype/test_npy/test_bytes.py

@@ -140,6 +140,13 @@ class TestVariableLengthBytes(BaseTestZDType):
     item_size_params = (VariableLengthBytes(),)
 
 
+def test_vlen_bytes_alias() -> None:
+    """Test that "bytes" is an accepted alias for "variable_length_bytes" in JSON metadata"""
+    a = VariableLengthBytes.from_json("bytes", zarr_format=3)
+    b = VariableLengthBytes.from_json("variable_length_bytes", zarr_format=3)
+    assert a == b
+
+
 @pytest.mark.parametrize(
     "zdtype", [NullTerminatedBytes(length=10), RawBytes(length=10), VariableLengthBytes()]
 )