Add to Cart button not disabled if more then one product per display

if you have more then one product for a product display then the button disable code does not run.

This is becouse the disabeling code is in the else of “if(isset($form['product_id']['#options']) ){“ in the form_alter.

I fixed this on my copy by using an after_build function

function commerce_stock_form_alter(&$form, &$form_state, $form_id){
  if (strpos($form_id, "commerce_cart_add_to_cart_form") === 0) {
    
    $stock = array();
    // Check to see if product has attributes.
    // @todo: We don't have to do any of this do we?
    if(isset($form['product_id']['#options']) ){      
      $form['#after_build'][] = 'commerce_stock_form_after_build';
      .....


function commerce_stock_form_after_build($form, &$form_state) {
 $prod_id = $form['product_id']['#value']; 
 if ( isset($form['product_id']['#stock']) && isset($form['product_id']['#stock'][$prod_id]) ) {
   $prod_stock = $form['product_id']['#stock'][$prod_id]; 
   if(isset($prod_stock) && ($prod_stock < 1) ){
     $form['submit']['#access'] = FALSE;
   } 
 }
  return $form;
}

One issue i had was that the $form['submit']['#disabled'] dose not work in the after_build, but i think it is better to hide the button, this will also resolve the Text instead of a disabled button.

one other small observetion the line:
$form['product_id']['#stock'] = $stock;
asignes the array of the items to each item so product 1 will have an array of stock levels for products 1...x, this is a bit waistfull and makes for harder coding in the validation functions.
i think that using the line
$form['product_id']['#stock'] = $stock[$key];
should work better as the actual stock count is assigned to the product

Please let me know if you need more information or help, i can send you my changed unit if you wish or try and figure out how to build a patch (haven't got around to it using Git mutch)