hope it helps.

<?php
/*
Plugin Name: changes anonymous to member's login if display name missing  (plugin for WordPress)
*/
function no_anonymous_members($author) { // this is a WORDPRESS plugin, not bbPress
global $comment;
if (empty($comment->comment_author) && !empty($comment->user_id)) {$user=get_userdata($comment->user_id); $author=$user->user_login;}
return $author;
} add_filter('get_comment_author', 'no_anonymous_members');

if ( !function_exists('get_userdata') ) :
function get_userdata( $user_id ) {
	global $wpdb;

	$user_id = absint($user_id);
	if ( $user_id == 0 )
		return false;

	$user = wp_cache_get($user_id, 'users');

	if ( $user ) {
		if (empty($user->display_name)) {$user->display_name=$user->user_login;}
		return $user;
	}
	if ( !$user = $wpdb->get_row($wpdb->prepare("SELECT * FROM $wpdb->users WHERE ID = %d LIMIT 1", $user_id)) ) {
		return false;
	}
	_fill_user($user);
	if (empty($user->display_name)) {$user->display_name=$user->user_login;}
	return $user;
}
endif;
?>

(The real answer of course is to insert the user_login when the comment is posted, however I cannot find a suitable hook in WordPress's comment-template.php so I am doing it by completely replacing the get_userdata function in pluggable.php)

update: actually it's as simple as this in phpMyAdmin:

UPDATE wp_users SET display_name=user_login WHERE display_name=''

or via a mini-plugin:

<?php
/*
Plugin Name: Fix Anonymous Members
*/
function fix_anonymous() {global $bbdb;
$bbdb->query("UPDATE $bbdb->users SET display_name=user_login WHERE display_name='' ");
} add_action('bb_init','fix_anonymous');
?>

save as _fix-anonymous.php (with leading underscore)
you only need to upload and run bbpress once with it loaded (no activation required) and then delete the plugin or it will slow down bbPress.

I am now writing a WordPress plugin to fix this without having to duplicate all the names in the table which is a horrendous waste of space.

The question is, why is this suddenly happening when bbPress is supposed to create it already. This might be a question for Sam - but I hope he can reproduce the problem.

Did you add the above code to insert the display name?

I hope I didn't lead you wrong by implying you should try 2.6 because that will be incompatible with bbPress 0.9
2.6 has compatibility with bbPress 1.0 alpha but a few plugins won't work with the alpha yet (like bb-topic-views)

Oh and the display name persists in 1.0 alpha and is on line 487 in pluggable. I've filed a trac report:
http://trac.bbpress.org/ticket/922

I am going to update to 2.6 and see how it goes...

But I could have sworn this was fixed in bbPress 0.9 with the WordPress Integration section built in. It should give the users a WordPress role and display name. Actually, WordPress should create the display name itself if it sees a user name without a display name. I wonder if this is a WP 2.6 issue which should not be used with bbPress 0.9

I think the same. In a forum it doesn't make much sense. What if i want to send a private message to a user ? If he changes his display name and avatar it could be very hard to find who he really is. It shouldn't be allowed in a forum with a lot of users, it could get extremely chaotic.

Glad you got it working but I really dislike "display names" and I think it's the worst concept in WordPress. Very bad idea to allow users to spoof other names. Even the "impostercide" plugin doesn't solve all the issues. No other blog/forum system has such a quirky concept.

BTW make sure you do NOT use the "Display Name" plugin for bbPress. It has a great deal of issues with other plugins and causes some weird behavior.

Also I'll take another look at my integration settings but i've been through it a lot already trying to get it to work today.

Cheers again!
KJ

pluggable.php in bb-includes

Line 502
$bbdb->insert( $bbdb->users,
compact( 'user_login', 'user_pass', 'user_nicename', 'user_email', 'user_url', 'user_registered' )
);

Replace with

// bbPress / WordPress bug fix added display name to wordpress
$display_name = $user_login;
$bbdb->insert( $bbdb->users,
compact( 'user_login', 'user_pass', 'user_nicename', 'user_email', 'user_url', 'user_registered', 'display_name' )
);

As far as your other observations (and I felt he same way in the beginning too) you have to realize that (easy) integration was only a priority starting with 0.9

(you can see how complicated the process used to be under 0.8 here - note most of that is not needed now)

Until 0.9, bbPress was just something that ran wordpress.org for Matt and there was no attitude to make integration work. There were tons of problems with usernames etc. and all integration had to be done manually with lots of plugins to fix things.

Then attitudes changed when Matt got funding and decided to use the bbPress code to power TalkPress (essentially forums for users on WordPress.com) Sam and MDA have done a great deal of work to make integration work better but it definitely has a way to go (and should become painless and super-easy IMHO).

So 0.9 has made integration easier but keep in mind bbPress is not even 1.0 yet, so officially it's not even a released product. The radical cookie changes in 2.6 will take awhile for bbPress to catchup, it's always been that way.

ps. if it's not obvious, I am in no way officially associated with Automattic/WordPress/bbPress. Just a plugin developer. And I am not paid. My opinions are definitely just my own and not any kind of official statement.

bbPress and WordPress are both great pieces of software in their own right, but when it comes to integration with each other they are pretty weak. For example, the new bbPress isn't compatible with WordPress 2.6 because of an issue with cookie management in WordPress... for the integration to work we now have to wait for bbPress to release an update which according to a moderator on here will be a while away.

There are also so many unsolved integration threads here that it's very difficult to find any one collection of possible solutions. I appreciate the amount of work that goes into this kind of software and time required to provide support. I'm just feeling a bit frustrated :(