We have a website long setup with both the "Require Login" module and the "simpleSAMLphp Authentication" module. I recently was running through some Drupal core and module updates and updated "Require Login" but not "simpleSAMLphp Authentication" (because it didn't have an update). After doing so, when going to the hardcoded login path ("/saml_login") provided by "simpleSAMLphp Authentication" it kept redirecting back and forth between that and "/home" which is what Require Login is set to.
This happened even in a fresh browser and Incognito mode.
Secondarily, I was testing a separate login module, SAML Auth (to take the place of the other one) and the client was running into a redirect loop at a different point in the process. I suspect the cause is the same.
Install and enable both "simpleSAMLphp Authentication" (latest version, they hardly ever update) and "Require Login" 3.0.4.
In Require Login...
Login path: /saml_login
Login destination: /home
Excluded paths:
/user/login
/welcome
/
Another side note, in the 2.4 version I came from, there is still the "Excluded route names" option under "Advanced Settings". But that no longer exists in the 3.0.4 version. In that I had the following:
simplesamlphp_auth.saml_login
samlauth.saml_controller_login
samlauth.saml_controller_logout
samlauth.saml_controller_metadata
samlauth.saml_controller_acs
samlauth.saml_controller_sls
samlauth.saml_controller_changepw
After configuring that, make sure SimpleSAML is enabled.
Ok, now try to go to "/saml_login" and watch as it redirects endlessly until your browser screams "Uncle"!!!!
I suspect that missing setting might be the problem child here. I recommend restoring that functionality.
Closed: works as designed
3.0
Code
3.x no longer excludes 3rd party routes by default. As stated in similar tickets and on the project page, you must install the https://www.drupal.org/project/route_condition → module to exclude paths by route name. After it's installed add whatever SAML routes you'd like to exclude from the redirect.