It looks like the way our function callback flags are specified in sm is not correct according to the docs. Our callbacks look like this:

JSFunctionSpec internal_cursor_functions[] = {

{ "hasNext" , internal_cursor_hasNext , 0 , 0 , JSPROP_READONLY | JSPROP_PERMANENT }

,

{ "next" , internal_cursor_next , 0 , 0 , JSPROP_READONLY | JSPROP_PERMANENT }

,

{ 0 }

};

And according to the docs the JSPROP flags are supposed to be in the fourth field, not the fifth field.
<https://developer.mozilla.org/En/SpiderMonkey/JSAPI_Reference/JSFunctionSpec>

I'm happy to work on this myself, just wanted to run it by you first.