py: boolean-mask keys raise NotImplementedError, not TypeError

h5py supports boolean masks for reads and writes; clawhdf5 supports
neither, so a mask is an unsupported operation (NotImplementedError, as
for every other edit the bindings cannot do), not an invalid key.

Tests: test_unsupported_edits_are_clear_errors (1-D, N-D and per-axis
mask writes, file unchanged) and test_boolean_masks_are_refused (reads).

Co-Authored-By: Claude Opus 5.5 (1M context) <[email protected]>

crates/clawhdf5-py/README.md

@@ -43,8 +43,9 @@ with clawhdf5.File("data.h5", "r") as f:
   Other types raise `TypeError`.
 - Keys are h5py's: integers, slices with a positive step, `...`, one
   increasing list of integers, compound field names. Each maps onto a
-  hyperslab selection. `None`, negative steps and boolean masks are refused
-  with h5py's errors.
+  hyperslab selection. `None` and negative steps are refused
+  with h5py's errors; boolean masks (which h5py supports) raise
+  `NotImplementedError`, for reads and writes.
 - What is read from the file: a selection whose bounding box covers at
   most half the dataset decodes only the chunks (or contiguous rows) the box
   overlaps. The library decodes the whole dataset for a larger box

crates/clawhdf5-py/src/select.rs

@@ -7,11 +7,12 @@
 //! (negative from the end) drop their axis, slices must have a positive
 //! step, one `Ellipsis` fills the unmentioned axes, a single increasing list
 //! of integers may index one axis, and strings name compound fields.
-//! Everything else (`None`/`np.newaxis`, boolean masks, several index lists)
-//! is refused with the error h5py gives.
+//! Everything else (`None`/`np.newaxis`, several index lists) is refused
+//! with the error h5py gives; boolean masks, which h5py supports, raise
+//! `NotImplementedError`.
 
 use clawhdf5_format::selection::Selection;
-use pyo3::exceptions::{PyIndexError, PyTypeError, PyValueError};
+use pyo3::exceptions::{PyIndexError, PyNotImplementedError, PyTypeError, PyValueError};
 use pyo3::prelude::*;
 use pyo3::types::{PyEllipsis, PySlice, PyString, PyTuple};
 
@@ -379,8 +380,10 @@ fn parse_axis(py: Python<'_>, a: &Bound<'_, PyAny>, n: u64) -> PyResult<Axis> {
         let arr = np.call_method1("asarray", (a,))?;
         let kind: String = arr.getattr("dtype")?.getattr("kind")?.extract()?;
         if kind == "b" {
-            return Err(PyTypeError::new_err(
-                "Boolean mask indexing is not supported by clawhdf5",
+            // h5py supports masks; clawhdf5 does not (yet), for reads or
+            // writes: an unsupported operation, not a wrong key.
+            return Err(PyNotImplementedError::new_err(
+                "boolean mask indexing is not supported by clawhdf5",
             ));
         }
         let ndim: usize = arr.getattr("ndim")?.extract()?;

crates/clawhdf5-py/tests/test_edit.py

@@ -643,6 +643,13 @@ def test_unsupported_edits_are_clear_errors(h5py, tmp_path):
             f["chunk_ext"].resize(3, axis=2)
         with pytest.raises(TypeError):
             f["i4"][0] = np.array(["a"] * 10)
+        # h5py writes through boolean masks; clawhdf5 does not.
+        with pytest.raises(NotImplementedError, match="mask"):
+            f["u1"][np.arange(16) % 2 == 0] = 5
+        with pytest.raises(NotImplementedError, match="mask"):
+            f["i4"][f["i4"][()] > 30] = 0
+        with pytest.raises(NotImplementedError, match="mask"):
+            f["i4"][np.ones(6, dtype=bool), 2] = 0
     assert snapshot(h5py, path) == before
     h5dump_reads(path)
 

crates/clawhdf5-py/tests/test_read_vs_h5py.py

@@ -440,7 +440,7 @@ def test_unsupported_types_are_errors_not_data(pair):
 
 def test_boolean_masks_are_refused(pair):
     ours, _, _ = pair
-    with pytest.raises(TypeError):
+    with pytest.raises(NotImplementedError, match="mask"):
         ours["num/le_i4_1d"][np.ones(37, dtype=bool)]