Prevent creation of multiple orders

1. +++ b/salsa_commerce.module
   @@ -189,14 +189,14 @@ function salsa_commerce_donate_order_create_validate($form, &$form_state) {
    function salsa_commerce_create_order($form, &$form_state) {
   -  // Create a new order.
   -  if (!isset($form_state['order'])) {
   +  // Create a new order or get the existing one from the session.
   +  if (!isset($_SESSION['salsa_commerce']['order_id'])) {
        $order = commerce_order_new($GLOBALS['user']->uid);
   

   We need more context here. If you visit another donation page, then this shouldn't persist. Even more so with p2p donations and so on. Get it from form_state or pass a context to the method so that yo ucan define a unique key in the session instead of order_id.

2. +++ b/salsa_commerce.module
   @@ -252,12 +252,87 @@ function salsa_commerce_create_order($form, &$form_state) {
   +  // Fetch existing line item and delete it in order to add a new one later on.
   +  if (isset($_SESSION['salsa_commerce']['line_item_id'])) {
   +    commerce_line_item_delete($_SESSION['salsa_commerce']['line_item_id']);
   +    unset($order_wrapper->commerce_line_items);
   +  }
   

   why do we need it for the line item exactly? can't we just delete the one that's currently in the order?

3. +++ b/salsa_commerce.module
   @@ -484,6 +548,9 @@ function salsa_commerce_commerce_checkout_complete($order) {
   +
   +  // Order was completed so user is allowed to begin a new order now.
   +  unset($_SESSION['salsa_commerce']);
   

   this needs to get more flexible too then and needs to look for the order ID in the list of keys and unset just that.

Just one final thing, looks good otherwise.

+++ b/salsa_commerce.module
@@ -483,6 +553,21 @@ function salsa_commerce_commerce_checkout_complete($order) {
     salsa_commerce_save_donation($order, $donation_line_item);
+    $line_item_wrapper = entity_metadata_wrapper('commerce_line_item', $donation_line_item);
+
+    // Order was completed so user is allowed to begin a new order now.
+    if ($donate_page = $line_item_wrapper->salsa_donate_page->value()) {
+      $order_key = 'donate_page:' . $donate_page->donate_page_KEY;
+    }
+    elseif ($supporter_my_donate_page = $line_item_wrapper->salsa_supporter_my_donate_page->value()) {
+      $order_key = 'my_donate_page:' . $supporter_my_donate_page->supporter_my_donate_page_KEY;
+    }
+    unset($_SESSION['salsa_commerce'][$order_key]);
+  }

I think just looping over the list and deleting the one with the current order ID whould be simpler.

then you can also move it out of the line item loop.

Thanks, committed.