Comment 4 for bug 731647

Also related to this, is that when you try to upload a file that contains duplicate users, it generates a warning message:

[WAR] e8 (lib/mahara.php:1123) Object of class stdClass could not be converted to string
Call stack (most recent first):

    log_message("Object of class stdClass could not be converted to...", 8, true, true, "/home/aaronw/www/mahara/htdocs/lib/mahara.php", 1123) at /home/aaronw/www/mahara/htdocs/lib/errors.php:446
    error(4096, "Object of class stdClass could not be converted to...", "/home/aaronw/www/mahara/htdocs/lib/mahara.php", 1123, array(size 3)) at Unknown:0
    sprintf("Line %s of the file specifies a remote username "%...", 4, "Polly", object(stdClass)) at Unknown:0
    call_user_func_array("sprintf", array(size 4)) at /home/aaronw/www/mahara/htdocs/lib/mahara.php:1123
    format_langstring("Line %s of the file specifies a remote username "%...", array(size 3), "en.utf8") at /home/aaronw/www/mahara/htdocs/lib/mahara.php:496
    get_string_location("uploadcsverrorremoteusertaken", "admin", array(size 3)) at /home/aaronw/www/mahara/htdocs/lib/mahara.php:293
    get_string("uploadcsverrorremoteusertaken", "admin", 4, "Polly", object(stdClass)) at /home/aaronw/www/mahara/htdocs/admin/users/uploadcsv.php:338
    uploadcsv_validate(object(Pieform), array(size 16)) at Unknown:0
    call_user_func_array("uploadcsv_validate", array(size 2)) at /home/aaronw/www/mahara/htdocs/lib/pieforms/pieform.php:1324
    Pieform->validate(array(size 16)) at /home/aaronw/www/mahara/htdocs/lib/pieforms/pieform.php:492
    Pieform->__construct(array(size 4)) at /home/aaronw/www/mahara/htdocs/lib/pieforms/pieform.php:161
    Pieform::process(array(size 4)) at /home/aaronw/www/mahara/htdocs/lib/pieforms/pieform.php:71
    pieform(array(size 4)) at /home/aaronw/www/mahara/htdocs/admin/users/uploadcsv.php:646

We should clean that up.