Notice when activating an account on a multisite config

[imath]

Hi,

Since [28373], when a user clicks on the account activation url (eg: site.url/wp-activate.php?key=key) from the activation email he received, the activation page is throwing a notice:
Notice: Undefined index: blog_id in path_to\wp-activate.php on line 108

Applying the diff attached to this ticket seems to avoid this notice.

[DrewAPicture]

I don't think 29191.diff​ addresses the wider issue of why blog_id would be set but null. We know, for instance, that blog_id is directly set in the $result array returned from wpmu_activate_signup(), So the problem has to be in wpmu_create_blog() or further down the line.

As many Multisite functions simply fallback to the current blog ID when $blog_id is null, it's not surprising this just popped up after removing the extract() in [28373].

[imath]

If it can help, i think i should detail a bit more how i got the notice.

I've added a new user from the /wp-admin/user-new.php of the root blog of the network. In this screen the form let you set the login, the mail, the role and whether to skip confirmation email or not. I've left the noconfirmation checkbox empty.

So i think, in this case, that wpmu_signup_blog() is not used but only wpmu_signup_user().

Then the email was sent to the user. And when the user clicks on the activation link, he arrives on /wp-activate.php and gets his login, password..

I think, in my case, that wpmu_activate_signup() stops at line 1038 with :
return array( 'user_id' => $user_id, 'password' => $password, 'meta' => $meta );

So no blog_id argument in the returned array.

[wonderboymusic]

In 29554:

wpmu_activate_signup() returns an array or WP_Error. The array keys it returns can be different based on context of $signup. The return value was previously extract()'d, so the value of $blog_id was secretly undefined when being passed to get_blogaddress_by_id() in some cases.

If $result['blog_id'] is not set, make sure $url is set to an empty string so that the proper "activated" message is shown to the user.

Props imath.
See [28373].
Fixes #29191.