[New-bugs-announce] [issue32998] regular expression regression in python 3.7

[mike bayer]

New submission from mike bayer <mike_mp at zzzcomputing.com>:

demo:

import re

inner = 'VARCHAR(30) COLLATE "en_US"'

result = re.sub(
    r'((?: COLLATE.*)?)$',
    r'FOO\1',
    inner
)

print(inner)
print(result)


in all Python versions prior to 3.7:

    VARCHAR(30) COLLATE "en_US"
    VARCHAR(30)FOO COLLATE "en_US"

in Python 3.7.0b2:

    VARCHAR(30) COLLATE "en_US"
    VARCHAR(30)FOO COLLATE "en_US"FOO

platform: Fedora 27 
python build:
Python 3.7.0b2 (default, Mar  5 2018, 09:37:32) 
[GCC 7.2.1 20170915 (Red Hat 7.2.1-2)] on linux

----------
components: Library (Lib)
messages: 313251
nosy: zzzeek
priority: normal
severity: normal
status: open
title: regular expression regression in python 3.7
type: behavior
versions: Python 3.7

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Python tracker <report at bugs.python.org>
<https://bugs.python.org/issue32998>
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