Description of problem:

Attempting to create a new account with an alternate username when the account
already exists may result in a traceback.

Steps to Reproduce:
1. Create an account
2. Log out
3. Attempt to create another account with a different username, but keep all
other information the same

This was uncovered by Scott Glaser when he forgot about his existing account and
attempted to create a new one.

This should result in a friendly error message that tells the user what is
happening.

His traceback from http://rafb.net/paste/results/lnSAhS74.html :
INSERT INTO person (username, human_name, email, gpg_keyid, ssh_key, password,
comments, postal_address, affiliation, telephone, facsimile, approval_status)
VALUES ('sglaser', 'Scott Glaser', 'sonar_guy', '599000BD', 'ssh-dss
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
sglaser.com', '726902', '', '1001 Birch Lake Crescent APT #
202', '', '757-428-0817', '', 'approved')
 
Traceback (most recent call last):
  File "/var/www/html/admin/accounts/userbox.cgi", line 180, in do_action
    field_values)
  File "/var/www/html/admin/accounts/pgdb.py", line 184, in execute
    self.executemany(operation, (params,))
  File "/var/www/html/admin/accounts/pgdb.py", line 199, in executemany
    rows = self.__source.execute(sql)
_pg.error: ERROR:  duplicate key violates unique constraint "person_email_key"
 
 
SELECT * FROM person WHERE username = 'sglaser' --> -->
Your full name: 	
 
 
 
_pg.error	Python 2.2.3: /usr/bin/python2
Tue Jan 3 22:54:39 2006
 
A problem occurred in a Python script. Here is the sequence of function calls
leading up to the error, in the order they occurred.
 
 /var/www/html/admin/accounts/userbox.cgi
  298     if action_error:
  299         print action_error
  300     do_form(form, fields, action, got_submit)
  301     if username and action=='edit':
  302         website.handle_group_mods(dbh, form, 'userbox.cgi', username,
do_form = <function do_form>, form = FieldStorage(None, None,
[FieldStorage('human_na... ''), FieldStorage('_createme', None, 'Submit')]),
fields = ({'can_edit': 0, 'check': <function check_notempty>, 'desc': 'Your full
name', 'maxlen': 50, 'name': 'human_name'}, {'can_edit': 0, 'check': <function
check_username>, 'desc': 'Username', 'maxlen': 8, 'name': 'username'}, {'check':
<function check_email>, 'desc': 'E-mail address', 'maxlen': 80, 'name': 'email',
'notes': 'Your E-mail address must be the one you use for your GPG key and
bugzilla account'}, {'check': <function check_notempty>, 'desc': 'Postal
Address', 'maxlen': 1024, 'name': 'postal_address'}, {'check': <function
check_notempty>, 'desc': 'Telephone', 'maxlen': 128, 'name': 'telephone'},
{'desc': 'Facsimile', 'maxlen': 128, 'name': 'facsimile'}, {'desc':
'Affiliation', 'maxlen': 64, 'name': 'affiliation'}, {'check': <function
check_gpg_keyid>, 'desc': '<a
href="http://fedoraproject.org/wiki/DocsProject/UsingGpg/CreatingKeys">GPG
KeyID</a>', 'maxlen': 16, 'name': 'gpg_keyid'}, {'check': <function
check_sshkey>, 'desc': 'SSHv2 Public Key (attach your ~/.ssh/id_dsa.pub file
here)', 'maxlen': 2048, 'name': 'ssh_key', 'strip': 1, 'type': 'file'},
{'check': <function check_notempty_onnew>, 'desc': 'Password', 'edit_reuse': 0,
'maxlen': 20, 'name': 'password', 'type': 'password'}, {'check': <function
check_double_password>, 'db_field': 0, 'desc': 'Password (again)', 'edit_reuse':
0, 'maxlen': 20, 'name': 'password_check', 'type': 'password'}, {'desc': 'IRC
nickname', 'maxlen': 32, 'name': 'ircnick'}, {'desc': 'Comments', 'maxlen':
1024, 'name': 'comments', 'skip_empty': 0}), action = 'create', got_submit = 1
 
 /var/www/html/admin/accounts/userbox.cgi in do_form(form=FieldStorage(None,
None, [FieldStorage('human_na... ''), FieldStorage('_createme', None,
'Submit')]), fields=({'can_edit': 0, 'check': <function check_notempty>, 'desc':
'Your full name', 'maxlen': 50, 'name': 'human_name'}, {'can_edit': 0, 'check':
<function check_username>, 'desc': 'Username', 'maxlen': 8, 'name': 'username'},
{'check': <function check_email>, 'desc': 'E-mail address', 'maxlen': 80,
'name': 'email', 'notes': 'Your E-mail address must be the one you use for your
GPG key and bugzilla account'}, {'check': <function check_notempty>, 'desc':
'Postal Address', 'maxlen': 1024, 'name': 'postal_address'}, {'check': <function
check_notempty>, 'desc': 'Telephone', 'maxlen': 128, 'name': 'telephone'},
{'desc': 'Facsimile', 'maxlen': 128, 'name': 'facsimile'}, {'desc':
'Affiliation', 'maxlen': 64, 'name': 'affiliation'}, {'check': <function
check_gpg_keyid>, 'desc': '<a
href="http://fedoraproject.org/wiki/DocsProject/UsingGpg/CreatingKeys">GPG
KeyID</a>', 'maxlen': 16, 'name': 'gpg_keyid'}, {'check': <function
check_sshkey>, 'desc': 'SSHv2 Public Key (attach your ~/.ssh/id_dsa.pub file
here)', 'maxlen': 2048, 'name': 'ssh_key', 'strip': 1, 'type': 'file'},
{'check': <function check_notempty_onnew>, 'desc': 'Password', 'edit_reuse': 0,
'maxlen': 20, 'name': 'password', 'type': 'password'}, {'check': <function
check_double_password>, 'db_field': 0, 'desc': 'Password (again)', 'edit_reuse':
0, 'maxlen': 20, 'name': 'password_check', 'type': 'password'}, {'desc': 'IRC
nickname', 'maxlen': 32, 'name': 'ircnick'}, {'desc': 'Comments', 'maxlen':
1024, 'name': 'comments', 'skip_empty': 0}), action='create', got_submit=1)
  129             cfunc = I.get('check')
  130             if cfunc:
  131                 objection = cfunc(form, I, curval, action)
  132         print "<tr><td align=left valign=top>"
  133         the_desc = I['desc']
objection = None, cfunc = <function check_username>, form = FieldStorage(None,
None, [FieldStorage('human_na... ''), FieldStorage('_createme', None,
'Submit')]), I = {'can_edit': 0, 'check': <function check_username>, 'desc':
'Username', 'maxlen': 8, 'name': 'username'}, curval = 'sglaser', action = 'create'
 
 /var/www/html/admin/accounts/userbox.cgi in
check_username(form=FieldStorage(None, None, [FieldStorage('human_na... ''),
FieldStorage('_createme', None, 'Submit')]), field_info={'can_edit': 0, 'check':
<function check_username>, 'desc': 'Username', 'maxlen': 8, 'name': 'username'},
value='sglaser', action='create')
   66         return "Invalid value"
   67     dbc = dbh.cursor()
   68     dbc.execute("SELECT * FROM person WHERE username = %s", (value,))
   69     rc = dbc.rowcount
   70     dbh.rollback()
dbc = <website.PostgresDBCursor instance>, dbc.execute = <bound method
pgdbCursor.execute of <pgdb.pgdbCursor instance>>, value = 'sglaser'
 
 /var/www/html/admin/accounts/pgdb.py in execute(self=<pgdb.pgdbCursor
instance>, operation='SELECT * FROM person WHERE username = %s',
params=('sglaser',))
  182 
  183         def execute(self, operation, params = None):
  184                 self.executemany(operation, (params,))
  185 
  186         def executemany(self, operation, param_seq):
self = <pgdb.pgdbCursor instance>, self.executemany = <bound method
pgdbCursor.executemany of <pgdb.pgdbCursor instance>>, operation = 'SELECT *
FROM person WHERE username = %s', params = ('sglaser',)
 
 /var/www/html/admin/accounts/pgdb.py in executemany(self=<pgdb.pgdbCursor
instance>, operation='SELECT * FROM person WHERE username = %s',
param_seq=(('sglaser',),))
  197                                 else:
  198                                         sql = operation
  199                                 rows = self.__source.execute(sql)
  200                                 if rows != None: # true is __source is NOT
a DQL
  201                                         totrows = totrows + rows
rows undefined, self = <pgdb.pgdbCursor instance>, self.__source undefined, sql
= "SELECT * FROM person WHERE username = 'sglaser'"
 
_pg.error: ERROR: current transaction is aborted, commands ignored until end of
transaction block