moves zarr3 to private module, adds test for zarr-python2 installs

Author: normanrz

.github/workflows/ci.yaml

@@ -15,6 +15,7 @@ jobs:
         python-version: ["3.10", "3.11", "3.12"]
         # macos-12 is an intel runner, macos-14 is a arm64 runner
         platform: [ubuntu-latest, windows-latest, macos-12, macos-14]
+        zarr-version: [">=2,<3", "==3.0.0b0"]
 
     steps:
       - name: Checkout source
@@ -68,7 +69,7 @@ jobs:
         shell: "bash -l {0}"
         run: |
           conda activate env
-          python -m pip install zarr==3.0.0b0
+          python -m pip install zarr${{ matrix.zarr-version }}
 
       # This is used to test with zfpy, which does not yet support numpy 2.0
       - name: Install older numpy and zfpy

numcodecs/zarr3.py renamed to numcodecs/_zarr3.py

@@ -13,7 +13,8 @@
 try:
     import zarr
 
-    assert zarr.__version__ >= "3.0.0"
+    if zarr.__version__ < "3.0.0":
+        raise ImportError("zarr 3.0.0 or later is required to use the numcodecs zarr integration.")
 except ImportError:
     raise ImportError("zarr 3.0.0 or later is required to use the numcodecs zarr integration.")
 

numcodecs/tests/test_zarr3_import.py

@@ -0,0 +1,13 @@
+from __future__ import annotations
+import pytest
+
+
+def test_zarr3_import():
+    try:
+        import zarr
+    except ImportError:
+        pass
+
+    if zarr is None or zarr.__version__ < "3.0.0":
+        with pytest.raises(ImportError):
+            import numcodecs._zarr3  # noqa: F401

pyproject.toml

@@ -72,26 +72,26 @@ pcodec = [
 ]
 
 [project.entry-points."zarr.codecs"]
-"numcodecs.blosc" = "numcodecs.zarr3:BloscCodec"
-"numcodecs.lz4" = "numcodecs.zarr3:Lz4Codec"
-"numcodecs.zstd" = "numcodecs.zarr3:ZstdCodec"
-"numcodecs.zlib" = "numcodecs.zarr3:ZlibCodec"
-"numcodecs.gzip" = "numcodecs.zarr3:GzipCodec"
-"numcodecs.bz2" = "numcodecs.zarr3:Bz2Codec"
-"numcodecs.lzma" = "numcodecs.zarr3:LzmaCodec"
-"numcodecs.shuffle" = "numcodecs.zarr3:ShuffleCodec"
-"numcodecs.delta" = "numcodecs.zarr3:DeltaCodec"
-"numcodecs.bitround" = "numcodecs.zarr3:BitroundCodec"
-"numcodecs.fixedscaleoffset" = "numcodecs.zarr3:FixedScaleOffsetCodec"
-"numcodecs.quantize" = "numcodecs.zarr3:QuantizeCodec"
-"numcodecs.packbits" = "numcodecs.zarr3:PackbitsCodec"
-"numcodecs.astype" = "numcodecs.zarr3:AsTypeCodec"
-"numcodecs.crc32" = "numcodecs.zarr3:Crc32Codec"
-"numcodecs.adler32" = "numcodecs.zarr3:Adler32Codec"
-"numcodecs.fletcher32" = "numcodecs.zarr3:Fletcher32Codec"
-"numcodecs.jenkins_lookup3" = "numcodecs.zarr3:JenkinsLookup3Codec"
-"numcodecs.pcodec" = "numcodecs.zarr3:PCodecCodec"
-"numcodecs.zfpy" = "numcodecs.zarr3:ZFPYCodec"
+"numcodecs.blosc" = "numcodecs._zarr3:BloscCodec"
+"numcodecs.lz4" = "numcodecs._zarr3:Lz4Codec"
+"numcodecs.zstd" = "numcodecs._zarr3:ZstdCodec"
+"numcodecs.zlib" = "numcodecs._zarr3:ZlibCodec"
+"numcodecs.gzip" = "numcodecs._zarr3:GzipCodec"
+"numcodecs.bz2" = "numcodecs._zarr3:Bz2Codec"
+"numcodecs.lzma" = "numcodecs._zarr3:LzmaCodec"
+"numcodecs.shuffle" = "numcodecs._zarr3:ShuffleCodec"
+"numcodecs.delta" = "numcodecs._zarr3:DeltaCodec"
+"numcodecs.bitround" = "numcodecs._zarr3:BitroundCodec"
+"numcodecs.fixedscaleoffset" = "numcodecs._zarr3:FixedScaleOffsetCodec"
+"numcodecs.quantize" = "numcodecs._zarr3:QuantizeCodec"
+"numcodecs.packbits" = "numcodecs._zarr3:PackbitsCodec"
+"numcodecs.astype" = "numcodecs._zarr3:AsTypeCodec"
+"numcodecs.crc32" = "numcodecs._zarr3:Crc32Codec"
+"numcodecs.adler32" = "numcodecs._zarr3:Adler32Codec"
+"numcodecs.fletcher32" = "numcodecs._zarr3:Fletcher32Codec"
+"numcodecs.jenkins_lookup3" = "numcodecs._zarr3:JenkinsLookup3Codec"
+"numcodecs.pcodec" = "numcodecs._zarr3:PCodecCodec"
+"numcodecs.zfpy" = "numcodecs._zarr3:ZFPYCodec"
 
 [tool.setuptools]
 license-files = ["LICENSE.txt"]