# Buggy code
def delete(request, mail_id):
    """Delete message selection.

    :param str mail_id: message unique identifier
    """
    mail_id = check_mail_id(request, mail_id)
    wrapper = get_wrapper()
    mb = (
        Mailbox.objects.get(user=request.user)
        if request.user.group == "SimpleUsers"
        else None
    )
    for mid in mail_id:
        r, i = mid.split()
        if mb is not None and r != mb.full_address and not r in mb.alias_addresses:
            continue
        msgrcpt = wrapper.get_recipient_message(r, i)
        msgrcpt.rs = "D"
        msgrcpt.save()
    message = ungettext(
        "%(count)d message deleted successfully",
        "%(count)d messages deleted successfully",
        len(mail_id),
    ) % {"count": len(mail_id)}
    return ajax_response(
        request,
        respmsg=message,
        url=QuarantineNavigationParameters(request).back_to_listing(),
    )


# Traceback (IntegrityError)
Internal Server Error: /quarantine/process/
Traceback (most recent call last):
File "/srv/modoboa/python-virtualenv-modoboa-1.1.1/local/lib/python2.7/site-packages/django/core/handlers/base.py", line 115, in get_response
response = callback(request, *callback_args, **callback_kwargs)
File "/srv/modoboa/python-virtualenv-modoboa-1.1.1/local/lib/python2.7/site-packages/django/contrib/auth/decorators.py", line 25, in _wrapped_view
return view_func(request, *args, **kwargs)
File "/srv/modoboa/python-virtualenv-modoboa-1.1.1/local/lib/python2.7/site-packages/modoboa/extensions/amavis/views.py", line 307, in process
return release(request, ids)
File "/srv/modoboa/python-virtualenv-modoboa-1.1.1/local/lib/python2.7/site-packages/modoboa/extensions/amavis/lib.py", line 30, in wrapped_f
return f(request, *args, **kwargs)
File "/srv/modoboa/python-virtualenv-modoboa-1.1.1/local/lib/python2.7/site-packages/modoboa/extensions/amavis/views.py", line 282, in release
rcpt.save()
File "/srv/modoboa/python-virtualenv-modoboa-1.1.1/local/lib/python2.7/site-packages/django/db/models/base.py", line 546, in save
force_update=force_update, update_fields=update_fields)
File "/srv/modoboa/python-virtualenv-modoboa-1.1.1/local/lib/python2.7/site-packages/django/db/models/base.py", line 626, in save_base
rows = manager.using(using).filter(pk=pk_val)._update(values)
File "/srv/modoboa/python-virtualenv-modoboa-1.1.1/local/lib/python2.7/site-packages/django/db/models/query.py", line 605, in _update
return query.get_compiler(self.db).execute_sql(None)
File "/srv/modoboa/python-virtualenv-modoboa-1.1.1/local/lib/python2.7/site-packages/django/db/models/sql/compiler.py", line 1020, in execute_sql
cursor = super(SQLUpdateCompiler, self).execute_sql(result_type)
File "/srv/modoboa/python-virtualenv-modoboa-1.1.1/local/lib/python2.7/site-packages/django/db/models/sql/compiler.py", line 846, in execute_sql
cursor.execute(sql, params)
File "/srv/modoboa/python-virtualenv-modoboa-1.1.1/local/lib/python2.7/site-packages/django/db/backends/util.py", line 41, in execute
return self.cursor.execute(sql, params)
File "/srv/modoboa/python-virtualenv-modoboa-1.1.1/local/lib/python2.7/site-packages/django/db/backends/mysql/base.py", line 122, in execute
six.reraise(utils.IntegrityError, utils.IntegrityError(*tuple(e.args)), sys.exc_info()[2])
File "/srv/modoboa/python-virtualenv-modoboa-1.1.1/local/lib/python2.7/site-packages/django/db/backends/mysql/base.py", line 120, in execute
return self.cursor.execute(query, args)
File "/usr/lib/python2.7/dist-packages/MySQLdb/cursors.py", line 174, in execute
self.errorhandler(self, exc, value)
File "/usr/lib/python2.7/dist-packages/MySQLdb/connections.py", line 36, in defaulterrorhandler
raise errorclass, errorvalue
IntegrityError: (1062, "Duplicate entry '0-NTFOxSLhytYl-1' for key 'PRIMARY'")

# Fixed code
def delete(request, mail_id):
    """Delete message selection.

    :param str mail_id: message unique identifier
    """
    mail_id = check_mail_id(request, mail_id)
    wrapper = get_wrapper()
    mb = (
        Mailbox.objects.get(user=request.user)
        if request.user.group == "SimpleUsers"
        else None
    )
    for mid in mail_id:
        r, i = mid.split()
        if mb is not None and r != mb.full_address and not r in mb.alias_addresses:
            continue
        wrapper.set_msgrcpt_status(r, i, "D")
    message = ungettext(
        "%(count)d message deleted successfully",
        "%(count)d messages deleted successfully",
        len(mail_id),
    ) % {"count": len(mail_id)}
    return ajax_response(
        request,
        respmsg=message,
        url=QuarantineNavigationParameters(request).back_to_listing(),
    )