better error string

Author: LDeakin

src/chunk_item.rs

@@ -109,7 +109,7 @@ impl WithSubset {
         // This permits broadcasting of a constant input.
         if subset.num_elements() != chunk_subset.num_elements() && subset.num_elements() > 1 {
             return Err(PyErr::new::<PyIndexError, _>(format!(
-                "subset {subset} and chunk subset {chunk_subset} differ in size",
+                "the size of the chunk subset {chunk_subset} and input/output subset {subset} are incompatible",
             )));
         }
         Ok(Self {

tests/test_pipeline.py

@@ -218,7 +218,7 @@ def test_ellipsis_indexing_invalid(arr: zarr.Array):
     stored_value = np.array([1, 2, 3])
     expected_errors = (
         "references array indices.*out-of-bounds of array shape",
-        "subset.*and chunk subset.*differ in size",
+        "the size of the chunk subset.*and input/output subset.* are incompatible",
     )
     with pytest.raises(IndexError, match="|".join(expected_errors)):
         arr[2, ...] = stored_value