pytype: add assertion to guide pytype through Whoosh usage

Mute pytype warnings:

File "kallithea/controllers/admin/admin.py", line 105, in _journal_filter: No attribute 'fieldname' on None [attribute-error]
  In Optional[Any]
File "kallithea/controllers/admin/admin.py", line 106, in _journal_filter: No attribute 'text' on None [attribute-error]
  In Optional[Any]
File "kallithea/controllers/admin/admin.py", line 107, in _journal_filter: No attribute 'startdate' on None [attribute-error]
  In Optional[Any]
File "kallithea/controllers/admin/admin.py", line 107, in _journal_filter: No attribute 'enddate' on None [attribute-error]
  In Optional[Any]

kallithea/controllers/admin/admin.py

@@ -1,147 +1,148 b''
 # -*- coding: utf-8 -*-
 # This program is free software: you can redistribute it and/or modify
 # it under the terms of the GNU General Public License as published by
 # the Free Software Foundation, either version 3 of the License, or
 # (at your option) any later version.
 #
 # This program is distributed in the hope that it will be useful,
 # but WITHOUT ANY WARRANTY; without even the implied warranty of
 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 # GNU General Public License for more details.
 #
 # You should have received a copy of the GNU General Public License
 # along with this program.  If not, see <http://www.gnu.org/licenses/>.
 """
 kallithea.controllers.admin.admin
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 
 Controller for Admin panel of Kallithea
 
 This file was forked by the Kallithea project in July 2014.
 Original author and date, and relevant copyright and licensing information is below:
 :created_on: Apr 7, 2010
 :author: marcink
 :copyright: (c) 2013 RhodeCode GmbH, and others.
 :license: GPLv3, see LICENSE.md for more details.
 """
 
 
 import logging
 
 from sqlalchemy.orm import joinedload
 from sqlalchemy.sql.expression import and_, func, or_
 from tg import request
 from tg import tmpl_context as c
 from whoosh import query
 from whoosh.qparser.dateparse import DateParserPlugin
 from whoosh.qparser.default import QueryParser
 
 from kallithea.controllers import base
 from kallithea.lib.auth import HasPermissionAnyDecorator, LoginRequired
 from kallithea.lib.indexers import JOURNAL_SCHEMA
 from kallithea.lib.page import Page
 from kallithea.lib.utils2 import remove_prefix, remove_suffix, safe_int
 from kallithea.model import db
 
 
 log = logging.getLogger(__name__)
 
 
 def _journal_filter(user_log, search_term):
     """
     Filters sqlalchemy user_log based on search_term with whoosh Query language
     http://packages.python.org/Whoosh/querylang.html
 
     :param user_log:
     :param search_term:
     """
     log.debug('Initial search term: %r', search_term)
     qry = None
     if search_term:
         qp = QueryParser('repository', schema=JOURNAL_SCHEMA)
         qp.add_plugin(DateParserPlugin())
         qry = qp.parse(search_term)
         log.debug('Filtering using parsed query %r', qry)
 
     def wildcard_handler(col, wc_term):
         if wc_term.startswith('*') and not wc_term.endswith('*'):
             # postfix == endswith
             wc_term = remove_prefix(wc_term, prefix='*')
             return func.lower(col).endswith(func.lower(wc_term))
         elif wc_term.startswith('*') and wc_term.endswith('*'):
             # wildcard == ilike
             wc_term = remove_prefix(wc_term, prefix='*')
             wc_term = remove_suffix(wc_term, suffix='*')
             return func.lower(col).contains(func.lower(wc_term))
 
     def get_filterion(field, val, term):
 
         if field == 'repository':
             field = getattr(db.UserLog, 'repository_name')
         elif field == 'ip':
             field = getattr(db.UserLog, 'user_ip')
         elif field == 'date':
             field = getattr(db.UserLog, 'action_date')
         elif field == 'username':
             field = getattr(db.UserLog, 'username')
         else:
             field = getattr(db.UserLog, field)
         log.debug('filter field: %s val=>%s', field, val)
 
         # sql filtering
         if isinstance(term, query.Wildcard):
             return wildcard_handler(field, val)
         elif isinstance(term, query.Prefix):
             return func.lower(field).startswith(func.lower(val))
         elif isinstance(term, query.DateRange):
             return and_(field >= val[0], field <= val[1])
         return func.lower(field) == func.lower(val)
 
     if isinstance(qry, (query.And, query.Term, query.Prefix, query.Wildcard,
                         query.DateRange)):
         if not isinstance(qry, query.And):
             qry = [qry]
         for term in qry:
+            assert term is not None, term
             field = term.fieldname
             val = (term.text if not isinstance(term, query.DateRange)
                    else [term.startdate, term.enddate])
             user_log = user_log.filter(get_filterion(field, val, term))
     elif isinstance(qry, query.Or):
         filters = []
         for term in qry:
             field = term.fieldname
             val = (term.text if not isinstance(term, query.DateRange)
                    else [term.startdate, term.enddate])
             filters.append(get_filterion(field, val, term))
         user_log = user_log.filter(or_(*filters))
 
     return user_log
 
 
 class AdminController(base.BaseController):
 
     @LoginRequired(allow_default_user=True)
     def _before(self, *args, **kwargs):
         super(AdminController, self)._before(*args, **kwargs)
 
     @HasPermissionAnyDecorator('hg.admin')
     def index(self):
         users_log = db.UserLog.query() \
                 .options(joinedload(db.UserLog.user)) \
                 .options(joinedload(db.UserLog.repository))
 
         # FILTERING
         c.search_term = request.GET.get('filter')
         users_log = _journal_filter(users_log, c.search_term)
 
         users_log = users_log.order_by(db.UserLog.action_date.desc())
 
         p = safe_int(request.GET.get('page'), 1)
 
         c.users_log = Page(users_log, page=p, items_per_page=10,
                            filter=c.search_term)
 
         if request.environ.get('HTTP_X_PARTIAL_XHR'):
             return base.render('admin/admin_log.html')
 
         return base.render('admin/admin.html')