Cleanup PCodec soft dependency

docs/release.rst

@@ -27,6 +27,8 @@ Fixes
 ~~~~~
 * Fixes issue with ``Delta`` Zarr 3 codec not working with ``astype``.
   By :user:`Norman Rzepka <normanrz>`, :issue:`664`
+* Cleanup ``PCodec`` soft dependency.
+  By :user:`John Kirkham <jakirkham>`, :issue:`647`
 
 
 Improvements

numcodecs/pcodec.py

@@ -1,14 +1,10 @@
 from typing import Literal, Optional
 
+from pcodec import ChunkConfig, DeltaSpec, ModeSpec, PagingSpec, standalone
+
 from numcodecs.abc import Codec
 from numcodecs.compat import ensure_contiguous_ndarray
 
-try:
-    from pcodec import ChunkConfig, DeltaSpec, ModeSpec, PagingSpec, standalone
-except ImportError:  # pragma: no cover
-    standalone = None
-
-
 DEFAULT_MAX_PAGE_N = 262144
 
 
@@ -58,9 +54,6 @@ def __init__(
         delta_encoding_order: Optional[int] = None,
         equal_pages_up_to: int = DEFAULT_MAX_PAGE_N,
     ):
-        if standalone is None:  # pragma: no cover
-            raise ImportError("pcodec must be installed to use the PCodec codec.")
-
         # note that we use `level` instead of `compression_level` to
         # match other codecs
         self.level = level

numcodecs/tests/test_pcodec.py

@@ -1,11 +1,8 @@
 import numpy as np
 import pytest
 
-from numcodecs.pcodec import PCodec
-
 try:
-    # initializing codec triggers ImportError
-    PCodec()
+    from numcodecs.pcodec import PCodec
 except ImportError:  # pragma: no cover
     pytest.skip("pcodec not available", allow_module_level=True)