re.VERBOSE doesn't respect whitespace in '( ?P<foo>...)'

[roysmith]

BPO	17184
Nosy	@ezio-melotti
Superseder	bpo-15606: re.VERBOSE whitespace behavior not completely documented

^{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 = None
closed_at = <Date 2013-02-15.21:08:18.721>
created_at = <Date 2013-02-11.19:39:08.799>
labels = ['expert-regex', 'type-bug', 'library']
title = "re.VERBOSE doesn't respect whitespace in '( ?P<foo>...)'"
updated_at = <Date 2013-02-15.21:08:18.719>
user = 'https://bugs.python.org/roysmith'

bugs.python.org fields:

activity = <Date 2013-02-15.21:08:18.719>
actor = 'ezio.melotti'
assignee = 'none'
closed = True
closed_date = <Date 2013-02-15.21:08:18.721>
closer = 'ezio.melotti'
components = ['Library (Lib)', 'Regular Expressions']
creation = <Date 2013-02-11.19:39:08.799>
creator = 'roysmith'
dependencies = []
files = []
hgrepos = []
issue_num = 17184
keywords = []
message_count = 2.0
messages = ['181927', '181931']
nosy_count = 3.0
nosy_names = ['roysmith', 'ezio.melotti', 'mrabarnett']
pr_nums = []
priority = 'normal'
resolution = 'duplicate'
stage = 'resolved'
status = 'closed'
superseder = '15606'
type = 'behavior'
url = 'https://bugs.python.org/issue17184'
versions = ['Python 2.7', 'Python 3.2', 'Python 3.3', 'Python 3.4']

[roysmith]

# Python 2.7.3
# Ubuntu 12.04

import re
pattern = r"( ?P<phrase>.*)"
regex = re.compile(pattern, re.VERBOSE)

The above raises an exception in re.compile():

Traceback (most recent call last):
  File "./try.py", line 6, in <module>
    regex = re.compile(pattern, re.VERBOSE)
  File "/home/roy/env/python/lib/python2.7/re.py", line 190, in compile
    return _compile(pattern, flags)
  File "/home/roy/env/python/lib/python2.7/re.py", line 242, in _compile
    raise error, v # invalid expression
sre_constants.error: nothing to repeat

The problem appears to be that re.VERBOSE isn't ignoring the space after the "(".

Maybe this is a duplicate of bpo-15606 ?

[mrabarnett]

It does look like a duplicate to me.