xrange repr broken for large arguments

[mdickinson]

BPO	16030
Nosy	@mdickinson, @vstinner
Dependencies	bpo-16029: pickle.dumps(xrange(sys.maxsize)) produces xrange(0)

^{Note: these values reflect the state of the issue at the time it was migrated and might not reflect the current state.}

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GitHub fields:

assignee = 'https://github.com/mdickinson'
closed_at = <Date 2012-09-28.19:51:15.088>
created_at = <Date 2012-09-24.21:23:17.295>
labels = ['interpreter-core', 'type-bug']
title = 'xrange repr broken for large arguments'
updated_at = <Date 2012-09-28.19:51:15.087>
user = 'https://github.com/mdickinson'

bugs.python.org fields:

activity = <Date 2012-09-28.19:51:15.087>
actor = 'mark.dickinson'
assignee = 'mark.dickinson'
closed = True
closed_date = <Date 2012-09-28.19:51:15.088>
closer = 'mark.dickinson'
components = ['Interpreter Core']
creation = <Date 2012-09-24.21:23:17.295>
creator = 'mark.dickinson'
dependencies = ['16029']
files = []
hgrepos = []
issue_num = 16030
keywords = []
message_count = 3.0
messages = ['171193', '171266', '171534']
nosy_count = 3.0
nosy_names = ['mark.dickinson', 'vstinner', 'python-dev']
pr_nums = []
priority = 'normal'
resolution = 'fixed'
stage = 'needs patch'
status = 'closed'
superseder = None
type = 'behavior'
url = 'https://bugs.python.org/issue16030'
versions = ['Python 2.7']

[mdickinson]

Python 2.7.3+ (2.7:f51d11405f1d+, Sep 24 2012, 21:39:19) 
[GCC 4.2.1 (Apple Inc. build 5664)] on darwin
Type "help", "copyright", "credits" or "license" for more information.
>>> import sys
>>> xrange(0, sys.maxint, sys.maxint-1)
xrange(0, -4, 9223372036854775806)

See also issue bpo-16029. There should be a common solution to both these issues. Suggestion is to write a 'range_safe_stop' utility function that returns r->start + r->len * r->step clipped to the range [LONG_MIN, LONG_MAX], and use that for the stop value in both the repr and the pickle.

[mdickinson]

The patch for issue bpo-16029 fixes this issue, too.

[python-dev]

New changeset bff269ee7288 by Mark Dickinson in branch '2.7':
Issues bpo-16029, bpo-16030: Fix pickling and repr of large xranges.
http://hg.python.org/cpython/rev/bff269ee7288