Issue 5828 - Additional paths require settings.ini

cms/sources.py

 # This file is part of the Adblock Plus web scripts,
 # Copyright (C) 2006-present eyeo GmbH
 #
 # Adblock Plus is free software: you can redistribute it and/or modify
 # it under the terms of the GNU General Public License version 3 as
 # published by the Free Software Foundation.
 #
 # Adblock Plus 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
@@ skipping 359 matching lines @@
     If `settings.ini` in the source contains `[paths]` section with an
     `additional-paths` key that contains the list of additional root folders,
     `MultiSource` will be instantiated and its bases will be the original
     source plus an additional source for each additional root folder.
     `MultiSource` looks up files in its base sources in the order they are
     provided, so the files in the additional folders will only be used if the
     original source doesn't contain that file.
     """
     source = FileSource(path)
 
-    config = source.read_config()
     try:
+        config = source.read_config()
         ap = config.get('paths', 'additional-paths').strip()
         additional_paths = filter(None, ap.split())
-    except (ConfigParser.NoSectionError, ConfigParser.NoOptionError):
+    except (ConfigParser.NoSectionError, ConfigParser.NoOptionError, IOError):
         additional_paths = []
 
     if additional_paths:
         additional_sources = [
             create_source(os.path.join(path, p))
             for p in additional_paths
         ]
         source = MultiSource([source] + additional_sources)
 
     if cached:
         for fname in [
             'list_files',
             'list_locales',
             'resolve_link',
             'read_config',
             'read_template',
             'read_locale',
             'read_file',
             'read_include',
             'exec_file',
         ]:
             setattr(source, fname, utils.memoize(getattr(source, fname)))
 
     return source