wp_upload_dir() produces incorrect URL if upload_path is empty
|Reported by:||tellyworth||Owned by:|
There was a bug in the patch at #5953. If the upload_path option is empty, it produces attachment URLs like http://example.com//2008/03/foo.jpg instead of http://example.com/wp-content/uploads/2008/03/foo.jpg. The filesystem path is correct, just the URL is broken. The enclosed patch fixes it.
I added a new unit test for the specific case, test_upload_dir_empty():