Function _slice_range

ormar/queryset/utils.py:235–264

Handles ``Model.objects[A:B]`` with both bounds set. Mixed-sign bounds (e.g. ``[3:-2]``) need a ``COUNT(*)`` to resolve so they are rejected; otherwise the sign of the bounds picks the forward or reverse variant. Examples:: [2:8] → _forward_range(2, 8) [-5:-2] →

(start: int, stop: int)

def _slice_range(start: int, stop: int) -> SliceBounds:
    """
    Handles ``Model.objects[A:B]`` with both bounds set. Mixed-sign bounds
    (e.g. ``[3:-2]``) need a ``COUNT(*)`` to resolve so they are rejected;
    otherwise the sign of the bounds picks the forward or reverse variant.

    Examples::

        [2:8]   → _forward_range(2, 8)
        [-5:-2] → _reverse_range(-5, -2)
        [3:-2]  → raises QueryDefinitionError (mixed sign)

    :param start: lower bound from the slice
    :type start: int
    :param stop: upper bound from the slice
    :type stop: int
    :return: normalized slice parameters
    :rtype: SliceBounds
    """
    start_neg = start < 0
    stop_neg = stop < 0
    if start_neg != stop_neg:
        raise QueryDefinitionError(
            "Mixed positive and negative slice bounds are not supported "
            "without an explicit count; use .count() with "
            ".offset()/.limit() instead."
        )
    if start_neg:
        return _reverse_range(start, stop)
    return _forward_range(start, stop)


def _forward_range(start: int, stop: int) -> SliceBounds: