Filters the comment author’s user ID before it is set.

The first time this filter is evaluated, user_ID is checked (for back-compat), followed by the standard user_id value.

$user_id int

The comment author's user ID.

File: wp-includes/comment.php. View all references

$commentdata['user_id'] = apply_filters( 'pre_user_id', $commentdata['user_ID'] );