Comment 9 for bug 985049

This is because the GECOS field contains a string starting with a '+' (for example a phone number) and the string that is replaced in the regex to anonymize user name is not escaped.

The code below is an excerpt of that reproduces the issue:
import re
p='My User-Name,12.123,+123456789,+123456789,'
for s in p.split(','):
    s = s.strip()
    if len(s) > 2:
        replacements.append((re.compile('\\b%s\\b' % s), 'User Name'))

The GECOS field should be escaped as it contains general information and forbidden characters in regexp.