FAPI loop in date.inc with jscalendar enabled

The $form['format'] = $formats['input']['text']; in the following code results in a FAPI loop on /node/add/<node-type>, but only if jscalendar is enabled and the date widget type is set to 'Text Field...'.

diff -u -p -r1.9.2.5 date.inc
--- date.inc    16 Sep 2006 16:16:12 -0000      1.9.2.5
@@ -997,7 +997,7 @@ function date_text_input($params) {
       '#description' => $description,
       '#weight' => $weight,
     );
=    $form['format'] = $formats['input']['text'];
   }

   // if the jscalendar is used for input, add some attributes to be passed to the js