Following the patches for bug #31500, we prompt for both a username and password whenever there is a missing SVN authorization file (i.e. first time commit) or the authorization file contains neither the password nor passtype keyword (*). When the authorization file exists then it will contain the username used in the first successful commit. So, when we detect that the authorization file exists and doesn't contain a password then we should only prompt for the password.
(*) This can occur when a person explicitly sets store-passwords = no and doesn't specify a value for password-stores in ~/.subversion/config. Then SVN will only cache usernames.
Is this still an issue?