py/objslice: Ensure slice is not hashable.

As per https://bugs.python.org/issue408326, the slice object should not be
hashable.  Since MicroPython has an implicit fallback when the unary_op
slot is empty, we need to fill this slot.

Signed-off-by: David Lechner <david@pybricks.com>
This commit is contained in:
David Lechner 2023-01-12 19:51:45 -06:00 committed by Damien George
parent eaccaa3677
commit 8491eb190f
2 changed files with 22 additions and 0 deletions

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@ -46,6 +46,12 @@ STATIC void slice_print(const mp_print_t *print, mp_obj_t o_in, mp_print_kind_t
mp_print_str(print, ")");
}
STATIC mp_obj_t slice_unary_op(mp_unary_op_t op, mp_obj_t o_in) {
// Needed to explicitly opt out of default __hash__.
// REVISIT: CPython implements comparison operators for slice.
return MP_OBJ_NULL;
}
#if MICROPY_PY_BUILTINS_SLICE_INDICES
STATIC mp_obj_t slice_indices(mp_obj_t self_in, mp_obj_t length_obj) {
mp_int_t length = mp_obj_int_get_checked(length_obj);
@ -104,6 +110,7 @@ MP_DEFINE_CONST_OBJ_TYPE(
mp_type_slice,
MP_QSTR_slice,
MP_TYPE_FLAG_NONE,
unary_op, slice_unary_op,
SLICE_TYPE_ATTR_OR_LOCALS_DICT
print, slice_print
);

15
tests/basics/slice_op.py Normal file
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@ -0,0 +1,15 @@
try:
t = [][:]
except:
print("SKIP")
raise SystemExit
# REVISIT: slice comparison operators are not implemented in MicroPython
# test that slice is not hashable, i.e. it can't be used to copy a dict
try:
{}[:] = {}
except TypeError:
print('TypeError')