UC Views creates a cart session cookie, breaks reverse proxy cache

Howdy!

Using debug_backtrace() I was able to find out that uc_views.views.inc gets called no matter what. (That in itself is news to me, but not surprising.)

Anyway, this bit of code:

/**
 * Implementation of hook_views_query_substitutions().
 */
function uc_views_views_query_substitutions($view) {
  return array('***CURRENT_CART_ID***' => uc_cart_get_id());
}

calls uc_cart_get_id() which, in its default state, creates a new session cookie ("uc_cart_id") which, when using a reverse proxy cache like Varnish, does not allow pages to be cached at that point.

The quick and easy solution is to throw FALSE into uc_cart_get_id so that a cart is not created if one is not already found. I've tested this, and it seems to work fine, but wanted to get others' feedback and input on this. I can write a patch so you can test it, if you like, but this is pretty quick and dirty. The new function looks thusly:

/**
 * Implementation of hook_views_query_substitutions().
 */
function uc_views_views_query_substitutions($view) {
  return array('***CURRENT_CART_ID***' => uc_cart_get_id(FALSE));
}

On our testing server this change allowed Varnish to cache and serve the pages (until of course an item is added to the cart). Thoughts?