If a feed requires a user name and password view HTTP authentication, e.g., a Drupal site protected by the PHP Authentication Shield module, then attempting to specify a password in the URL produces an error message if the password contains special characters.

Steps:

1. Go to https://[my domain]/import/[machine name of importer]
2. Under Import, specify an URL requiring HTTP authentication, including a password that has special characters, e.g. https://[site username]:[site password that includes, say $#\@]@[my domain]/[path to feed]

Actual result: Error message that URL contains invalid characters.
Expected result: Accepts special characters