Undefined index when creating account via OpenID

Relevant code:

    $form['name']['#default_value'] = $_SESSION['openid']['values']['name']; // #118
    $form['mail']['#default_value'] = $_SESSION['openid']['values']['mail']; // #119
    // If user_email_verification is off, hide the password field and just fill
    // with random password to avoid confusion.
    if (!variable_get('user_email_verification', TRUE)) {
      $form['pass']['#type'] = 'hidden';
      $form['pass']['#value'] = user_password();
    }
    $form['auth_openid'] = array('#type' => 'hidden', '#value' => $_SESSION['openid']['values']['auth_openid']); // #126

Diagnosis: $_SESSION['openid']['values'] isn't set.

Before the above code is executed, the function checks for the presence of $_SESSION['openid']:

  elseif ($form_id == 'user_register' && isset($_SESSION['openid'])) {
    ...
  }

This should probably be $_SESSION['openid']['values'], although I can't quite fathom why $_SESSION['openid'] would be set if ['values'] isn't.

Trivial patch. I couldn't reproduce the problem, so I can't test. Normally I'd suspect there might be more to it, but as the notices seem to be the only actual issue, this should be enough.

I think this can be reproduced as follows:
1. Login using your OpenID
2. Go to admin/user/user/create
3. See the notices
4. Inspect $_SESSION['openid'] and see that it contains the key "user_login_values"

Apparently code in question is meant for the "Create new account" form, after logging in with an unknown OpenID failed (e.g. because of "invalid username", which is likely to be the normalized OpenID).
It seems to get triggered in two cases where it's not meant to be:
1. When the admin creates a new user
2. in openid/authenticate?destination=user, after returning from the provider (there is also only the key "user_login_values" - when trying to login using an unknown OpenID for the first time).

I've came up with the same fix (extended isset()) and it appears that everything works alright afterwards. I've tested:
- Login using attached OpenID
- Login using unknown OpenID, with sreg.nickname (=> Autoregister)
- Attaching an OpenID to an existing user

This is still an issue in HEAD, I've re-rolled the patch for HEAD and tested it locally. I can create a separate issue if that is preferred.

The proposed fix was added to HEAD as part of #251245: openid.module needs tests.

Here is a backport for D6.

Thanks, committed to Drupal 6.