wp_notify_moderator() sends multiple emails to the same person if the email addresses are not the same case

[westi]

In the code we have:

$emails = array( get_option('admin_email') );
if ( user_can($user->ID, 'edit_comment', $comment_id) && !empty($user->user_email) && ( get_option('admin_email') != $user->user_email) )
    $emails[] = $user->user_email;

If the Post Author's email address is something like Foo@bar.com and the admin_email is foo@bar.com then we will send two emails to the same person.

While ​RFC2821 says:

The local-part of a mailbox MUST BE treated as case sensitive. Therefore, SMTP implementations MUST take care to preserve the case of mailbox local-parts. Mailbox domains are not case sensitive.

WordPress already treats email addresses as case insensitive in other places and places like gmail does too.

[SergeyBiryukov]

Introduced in [16223].

[SergeyBiryukov]

25779.patch​ uses strcasecmp() to compare emails in wp_notify_moderator(), wp_password_change_notification(), and revoke_super_admin(). These are all the instances I could find.

[SergeyBiryukov]

Fixed a typo

[SergeyBiryukov]

In 26115:

Use case-insensitive comparison for email addresses. fixes #25779.