deprecate zarr.storage.default_compressor

Author: brokkoli71

src/zarr/core/config.py

@@ -31,10 +31,10 @@ def reset(self) -> None:
 # The config module is responsible for managing the configuration of zarr and  is based on the Donfig python library.
 # For selecting custom implementations of codecs, pipelines, buffers and ndbuffers, first register the implementations
 # in the registry and then select them in the config.
-# e.g. an implementation of the bytes codec in a class "NewBytesCodec", requires the value of codecs.bytes.name to be
-# "NewBytesCodec".
+# e.g. an implementation of the bytes codec in a class "your.module.NewBytesCodec", requires the value of codecs.bytes
+# to be "your.module.NewBytesCodec".
 # Donfig can be configured programmatically, by environment variables, or from YAML files in standard locations
-# e.g. export ZARR_CODECS__BYTES__NAME="NewBytesCodec"
+# e.g. export ZARR_CODECS__BYTES="your.module.NewBytesCodec"
 # (for more information see github.com/pytroll/donfig)
 # Default values below point to the standard implementations of zarr-python
 config = Config(
@@ -71,7 +71,6 @@ def reset(self) -> None:
             },
             "buffer": "zarr.core.buffer.cpu.Buffer",
             "ndbuffer": "zarr.core.buffer.cpu.NDBuffer",
-
         }
     ],
 )

src/zarr/storage/__init__.py

@@ -1,3 +1,8 @@
+import sys
+import warnings
+from types import ModuleType
+from typing import Any
+
 from zarr.storage.common import StoreLike, StorePath, make_store_path
 from zarr.storage.local import LocalStore
 from zarr.storage.logging import LoggingStore
@@ -17,3 +22,20 @@
     "ZipStore",
     "make_store_path",
 ]
+
+
+class VerboseModule(ModuleType):
+    def __setattr__(self, attr: str, value: Any) -> None:
+        if attr == "default_compressor":
+            warnings.warn(
+                "setting zarr.storage.default_compressor is deprecated, use "
+                "zarr.config to configure array.v2_default_compressor "
+                "e.g. config.set({'codecs.zstd':'your.module.Zstd', 'array.v2_default_compressor.numeric': 'zstd'})",
+                DeprecationWarning,
+                stacklevel=1,
+            )
+        else:
+            super().__setattr__(attr, value)
+
+
+sys.modules[__name__].__class__ = VerboseModule

tests/test_v2.py

@@ -82,11 +82,7 @@ def test_codec_pipeline() -> None:
 
 @pytest.mark.parametrize("dtype", ["|S", "|V"])
 async def test_v2_encode_decode(dtype):
-    with config.set(
-        {
-            "array.v2_default_compressor.bytes": "vlen-bytes",
-        }
-    ):
+    with config.set({"array.v2_default_compressor.bytes": "vlen-bytes"}):
         store = zarr.storage.MemoryStore()
         g = zarr.group(store=store, zarr_format=2)
         g.create_array(
@@ -206,6 +202,11 @@ def test_v2_non_contiguous(array_order: Literal["C", "F"], data_order: Literal["
     np.testing.assert_array_equal(arr[slice(6, 9, None), slice(3, 6, None)], a)
 
 
+def test_default_compressor_deprecation_warning():
+    with pytest.warns(DeprecationWarning):
+        zarr.storage.default_compressor = "zarr.codecs.zstd.ZstdCodec()"
+
+
 @pytest.mark.parametrize(
     "dtype_expected",
     [["b", "zstd"], ["i", "zstd"], ["f", "zstd"], ["|S1", "vlen-bytes"], ["|U1", "vlen-utf8"]],