:mod:`sklearn.calibration`

- |Enhancement| :func:`calibration.calibration_curve` accepts a parameter

`pos_label` to specify the positive class label.

:pr:`21032` by :user:`Guillaume Lemaitre <glemaitre>`.

:mod:`sklearn.ensemble`

- |Fix| Fixed a bug that could produce a segfault in rare cases for

:class:`ensemble.HistGradientBoostingClassifier` and

:class:`ensemble.HistGradientBoostingRegressor`.

:pr:`21130` :user:`Christian Lorentzen <lorentzenchr>`.

if right_counts[thread_idx] > 0:

# If we're splitting the rightmost node of the tree, i.e. the

# rightmost node in the partition array, and if n_threads >= 2, one

# might have right_counts[-1] = 0 and right_offset[-1] = len(sample_indices)

# leading to evaluating

#

# &sample_indices[right_offset[-1]] = &samples_indices[n_samples_at_node]

# = &partition[n_samples_in_tree]

#

# which is an out-of-bounds read access that can cause a segmentation fault.

# When boundscheck=True, removing this check produces this exception:

#

# IndexError: Out of bounds on buffer access

#

memcpy(

&sample_indices[right_offset[thread_idx]],

&right_indices_buffer[offset_in_buffers[thread_idx]],

sizeof(unsigned int) * right_counts[thread_idx]

)