I just would like to help to figure out the answer. I tracked the source code myself, that help me understand how the :event => :authentication parameter works. I hope it also helps you. So your question is why pass the :event => :authentication to the sign_in_and_redirect method to force all authentication callbacks to be called. then, we can track the definition. # Sign in a user and tries to re
![What does ":event => :authentication" do?](https://cdn-ak-scissors.b.st-hatena.com/image/square/98d6f053a97a87156775f60757c60865d0f2c47d/height=288;version=1;width=512/https%3A%2F%2Ffanyv88.com%3A443%2Fhttps%2Fcdn.sstatic.net%2FSites%2Fstackoverflow%2FImg%2Fapple-touch-icon%402.png%3Fv%3D73d79a89bded)