[issue29816] Get rid of C limitation for shift count in right shift

[Serhiy Storchaka]

New submission from Serhiy Storchaka:

Currently the value of right operand of the right shift operator is limited by C Py_ssize_t type.

>>> 1 >> 10**100
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
OverflowError: Python int too large to convert to C ssize_t
>>> (-1) >> 10**100
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
OverflowError: Python int too large to convert to C ssize_t
>>> 1 >> -10**100
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
OverflowError: Python int too large to convert to C ssize_t
>>> (-1) >> -10**100
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
OverflowError: Python int too large to convert to C ssize_t

But this is artificial limitation. Right shift can be extended to support arbitrary integers. `x >> very_large_value` should be 0 for non-negative x and -1 for negative x. `x >> negative_value` should raise ValueError.

>>> 1 >> 10
0
>>> (-1) >> 10
-1
>>> 1 >> -10
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
ValueError: negative shift count
>>> (-1) >> -10
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
ValueError: negative shift count

----------
components: Interpreter Core
messages: 289650
nosy: Oren Milman, mark.dickinson, serhiy.storchaka
priority: normal
severity: normal
stage: needs patch
status: open
title: Get rid of C limitation for shift count in right shift
type: enhancement
versions: Python 3.7

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Python tracker <report at bugs.python.org>
<http://bugs.python.org/issue29816>
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