User profiles: Make sure all users have a displayname defined

[tobifjellner]

As far as I know, nowadays the system doesn't allow a user to clear out the displayname, but some profiles on wp-org don't have any displayname defined.

In some views this makes it harder to see the username of someone who has posted or commented.

I suggest that someone, as a one-time action, should search for all user profiles that have an empty displayname, and set it to the username.

[dd32]

For reference, on WordPress.org there's over 600,000 users who don't have a display_name set (out of 17+ million - user ID's aren't secret).

While it looks like it's the earlier users, there's a registered user as recently as 2019-07-23 who has a blank display name, although that just looks like because the HTML junk added to their Name field probably sanitized out to a blank string.