I don't know why people add a new "$wgCopyUploadsFromSpecialUpload" since 1.20.0.
But it creat bug in my wiki(1.22wmf9 (0727d6a))
I use to use
$wgGroupPermissions['autoconfirmed']['upload_by_url'] = true;
$wgAllowCopyUploads = true;
everything works fine.
After 1.20 the URL upload bar despaired and then I realized new configuration is :
$wgGroupPermissions['autoconfirmed']['upload_by_url'] = true;
$wgAllowCopyUploads = true;
$wgCopyUploadsFromSpecialUpload = true;
From http://www.mediawiki.org/wiki/Manual:$wgCopyUploadsFromSpecialUpload
However, when $wgCopyUploadsFromSpecialUpload = true; the system can't detect duplicate image and can't copy file name too.
Here is a screenshot when $wgCopyUploadsFromSpecialUpload set to false: http://i.imgur.com/JVImbF2.jpg
Here is another screenshot when $wgCopyUploadsFromSpecialUpload set to true, which is abnormal: http://i.imgur.com/3oBwXfd.jpg
And this is a link for testment: http://en.moegirl.org/Special:Upload
Version: 1.22.0
Severity: normal