Security bug fix:
If you use HttpAuthMiddleware (i.e. the http_user and http_pass spider attributes) for HTTP authentication, any request exposes your credentials to the request target.
To prevent unintended exposure of authentication credentials to unintended domains, you must now additionally set a new, additional spider attribute, http_auth_domain, and point it to the specific domain to which the authentication credentials must be sent.
If the http_auth_domain spider attribute is not set, the domain of the first request will be considered the HTTP authentication target, and authentication credentials will only be sent in requests targeting that domain.
If you need to send the same HTTP authentication credentials to multiple domains, you can use w3lib.http.basic_auth_header instead to set the value of the Authorization header of your requests.
If you really want your spider to send the same HTTP authentication credentials to any domain, set the http_auth_domain spider attribute to None.
Finally, if you are a user of scrapy-splash, know that this version of Scrapy breaks compatibility with scrapy-splash 0.7.2 and earlier. You will need to upgrade scrapy-splash to a greater version for it to continue to work.