You get the below error if you hit the next button on a user registration form that includes core account fields and is divied into 2 steps.
TypeError: key(): Argument #1 ($array) must be of type array, null given in key() (line 368 of ... /web/core/modules/user/src/AccountForm.php).
The same error message also comes up in another issue from 1.x branch that is linked. The call stack of this one differs from that one.
On a clean installation, add some fields to user. Create a two step registration form with help of this module.
A dirty fix attached. Please review or suggest.
Check out the the linked core issue: https://www.drupal.org/project/drupal/issues/3328962 🐛 TypeError: key(): Argument #1 ($array) must be of type array, string given in key() Needs work
Also chceck out the module description of the similar module Entity Form Steps: https://www.drupal.org/node/3281779/revisions/13136701/view →
Needs review
2.0
Code
Attached is a quick & dirty fix to keep the functionality of a dev branch of a project.
I have no idea if it can introduce a security vulnerability, since this is a user registration related process. Please don't use in production until RTBC.
So please review.