--- file-old.php	2010-02-18 11:12:34.000000000 -0800
+++ file.php	2010-02-18 11:12:50.000000000 -0800
@@ -220,6 +224,7 @@
  * @param array $file Reference to a single element of $_FILES. Call the function once for each uploaded file.
  * @param array $overrides Optional. An associative array of names=>values to override default variables with extract( $overrides, EXTR_OVERWRITE ).
  * @return array On success, returns an associative array of file attributes. On failure, returns $overrides['upload_error_handler'](&$file, $message ) or array( 'error'=>$message ).
+ * @todo I don't think it's correct to define the error handler for prefilter errors before running extract. -tychay
  */
 function wp_handle_upload( &$file, $overrides = false, $time = null ) {
 	// The default error handler.
@@ -258,6 +263,7 @@
 	// All tests are on by default. Most can be turned off by $override[{test_name}] = false;
 	$test_form = true;
 	$test_size = true;
+	$test_upload = true;
 
 	// If you override this, you must provide $ext and $type!!!!
 	$test_type = true;
@@ -269,19 +275,19 @@
 
 	// A correct form post will pass this test.
 	if ( $test_form && (!isset( $_POST['action'] ) || ($_POST['action'] != $action ) ) )
-		return $upload_error_handler( $file, __( 'Invalid form submission.' ));
+		return call_user_func($upload_error_handler, $file, __( 'Invalid form submission.' ));
 
 	// A successful upload will pass this test. It makes no sense to override this one.
 	if ( $file['error'] > 0 )
-		return $upload_error_handler( $file, $upload_error_strings[$file['error']] );
+		return call_user_func($upload_error_handler, $file, $upload_error_strings[$file['error']] );
 
 	// A non-empty file will pass this test.
 	if ( $test_size && !($file['size'] > 0 ) )
-		return $upload_error_handler( $file, __( 'File is empty. Please upload something more substantial. This error could also be caused by uploads being disabled in your php.ini or by post_max_size being defined as smaller than upload_max_filesize in php.ini.' ));
+		return call_user_func($upload_error_handler, $file, __( 'File is empty. Please upload something more substantial.' ));
 
 	// A properly uploaded file will pass this test. There should be no reason to override this one.
-	if (! @ is_uploaded_file( $file['tmp_name'] ) )
-		return $upload_error_handler( $file, __( 'Specified file failed upload test.' ));
+	if ( $test_upload && ! @ is_uploaded_file( $file['tmp_name'] ) )
+		return call_user_func($upload_error_handler, $file, __( 'Specified file failed upload test.' ));
 
 	// A correct MIME type will pass this test. Override $mimes or use the upload_mimes filter.
 	if ( $test_type ) {
@@ -289,8 +295,11 @@
 
 		extract( $wp_filetype );
 
+		/* WPCOM - Limit site admin uploads
 		if ( ( !$type || !$ext ) && !current_user_can( 'unfiltered_upload' ) )
-			return $upload_error_handler( $file, __( 'File type does not meet security guidelines. Try another.' ));
+		*/
+		if ( !$type || !$ext )
+			return call_user_func($upload_error_handler, $file, __( 'File type does not meet security guidelines. Try another.' ));
 
 		if ( !$ext )
 			$ext = ltrim(strrchr($file['name'], '.'), '.');
@@ -303,20 +312,32 @@
 
 	// A writable uploads dir will pass this test. Again, there's no point overriding this one.
 	if ( ! ( ( $uploads = wp_upload_dir($time) ) && false === $uploads['error'] ) )
-		return $upload_error_handler( $file, $uploads['error'] );
+		return call_user_func($upload_error_handler, $file, $uploads['error'] );
 
 	$filename = wp_unique_filename( $uploads['path'], $file['name'], $unique_filename_callback );