Registration page should display error message if user tries to register a duplicate account

[rstorey]

What behavior did you observe? Please describe the bug
The register page refreshed. The password and confirm password fields emptied.

How can we reproduce the bug?
Steps to reproduce the behavior:

1. Go to the Register page
2. Fill out the form and submit.
3. Go back to a blank Register page.
4. Fill out the form using the same username or email address as in the first try

What is the expected behavior?
If a user attempts to register either a username or email address that is already in use by another account, an error message should be displayed and the user should be prompted to use a different username / email address. Perhaps there should also be a link to the reset password page.

Desktop (please complete the following information):

• OS: MacOS
• Browser Chrome

[acdha]

The password fields employing is a security measure. This used to work and the form sets the invalid state on the email field so this was probably a template change suppressing display of the error message for that field since we chose not to use the standard Django forms.

[rstorey]

Yep. I only mentioned the password thing because that was the only way I could tell the page actually refreshed.

[rstorey]

https://github.com/twbs/bootstrap/blob/master/scss/mixins/_forms.scss#L46

[rstorey]

zostera/django-bootstrap4#147

[rstorey]

twbs/bootstrap#23454

[rstorey]

twbs/bootstrap#29439