Edited slice to recompress with original data cparams

Author: Luke Shaw

src/blosc2/ndarray.py

@@ -1839,8 +1839,13 @@ def slice(self, key: int | slice | Sequence[slice], **kwargs: Any) -> NDArray:
         """
         original_codec = self.cparams.codec
         original_clevel = self.cparams.clevel
+        original_filters = self.cparams.filters
         if "cparams" not in kwargs:
-            kwargs["cparams"] = {"codec": original_codec, "clevel": original_clevel}
+            kwargs["cparams"] = {
+                "codec": original_codec,
+                "clevel": original_clevel,
+                "filters": original_filters,
+            }
         kwargs = _check_ndarray_kwargs(**kwargs)  # sets cparams to defaults
         key, mask = process_key(key, self.shape)
         start, stop, step = get_ndarray_start_stop(self.ndim, key, self.shape)

tests/ndarray/test_slice.py

@@ -35,12 +35,16 @@ def test_slice_codec_and_clevel(shape, chunks, blocks, slices, dtype):
     size = int(np.prod(shape))
     nparray = np.arange(size, dtype=dtype).reshape(shape)
     a = blosc2.asarray(
-        nparray, chunks=chunks, blocks=blocks, cparams={"codec": blosc2.Codec.LZ4, "clevel": 6}
+        nparray,
+        chunks=chunks,
+        blocks=blocks,
+        cparams={"codec": blosc2.Codec.LZ4, "clevel": 6, "filters": [blosc2.Filter.BITSHUFFLE]},
     )
 
     b = a.slice(slices)
     assert b.cparams.codec == a.cparams.codec
     assert b.cparams.clevel == a.cparams.clevel
+    assert b.cparams.filters == a.cparams.filters
 
 
 argnames = "shape, chunks, blocks, slices, dtype, chunks2, blocks2"