[issue26202] The range() object is deepcopied as atomic

[Serhiy Storchaka]

New submission from Serhiy Storchaka:

The range() object is immutable, but is not atomic, and copy.deepcopy() shouldn't return it unchanged.

>>> class I(int): pass  # mutable index
... 
>>> import copy
>>> r = range(I(10))
>>> r2 = copy.deepcopy(r)
>>> r.stop.attr = 'spam'
>>> r2.stop.attr
'spam'

This is Python 3 only issue because in 2.7 the xrange() object doesn't exposes start/stop/step attributes.

Proposed patch fixes the copy module.

----------
components: Library (Lib)
files: deepcopy_range.patch
keywords: patch
messages: 258921
nosy: alexandre.vassalotti, fdrake, haypo, serhiy.storchaka
priority: normal
severity: normal
stage: patch review
status: open
title: The range() object is deepcopied as atomic
type: behavior
versions: Python 3.5, Python 3.6
Added file: http://bugs.python.org/file41714/deepcopy_range.patch

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Python tracker <report at bugs.python.org>
<http://bugs.python.org/issue26202>
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