[issue18723] shorten function of textwrap module is susceptible to non-normalized whitespaces

[Vajrasky Kok]

New submission from Vajrasky Kok:

In shorten function of textwrap module, the placeholder becomes a hole where we can inject non-normalized whitespaces to the text.

>>> text = "Hello there, how are you this fine day? I'm glad to hear it!"
>>> from textwrap import shorten
>>> shorten(text, 40, placeholder="              ")
'Hello there, how are you'

We normalize the only-whitespaces placeholder.

But....

>>> shorten(text, 17, placeholder="  \n\t(...)  \n\t[...]  \n\t")
'(...)  \n\t[...]'
>>> shorten(text, 40, placeholder="  \n\t(...)  \n\t[...]  \n\t")
'Hello there, how  \n\t(...)  \n\t[...]'

Attached the patch to normalize the non-normalized whitespaces in placeholder.

----------
components: Library (Lib)
files: fix_for_non_normalized_whitespaces_in_placeholder.patch
keywords: patch
messages: 195045
nosy: pitrou, vajrasky
priority: normal
severity: normal
status: open
title: shorten function of textwrap module is susceptible to non-normalized whitespaces
type: behavior
versions: Python 3.4
Added file: http://bugs.python.org/file31271/fix_for_non_normalized_whitespaces_in_placeholder.patch

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Python tracker <report at bugs.python.org>
<http://bugs.python.org/issue18723>
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