[FIX] point_of_sale,pos_restaurant: Multiprint

Printed receipts are transformed into images by placing them into an
hidden `div`. When trying to print multiple orders, we did not wait
correctly between rendering the different receipts. Receipts were then
overriding one another while they were being rendered, resulting in
errors and missing receipts.

closes odoo/odoo#43907

X-original-commit: 00ba908d7b3d8b1145e4161ea8d9011ff6eea33d
Signed-off-by: Antoine Prieëls <aprieels@users.noreply.github.com>

2 files changed, 6 insertions, 6 deletions

diff --git a/addons/point_of_sale/static/src/js/printers.js b/addons/point_of_sale/static/src/js/printers.js
index a18e0831427..3e4a21d96a5 100644
--- a/addons/point_of_sale/static/src/js/printers.js
+++ b/addons/point_of_sale/static/src/js/printers.js
@@ -22,14 +22,14 @@ var PrinterMixin = {
         function process_next_job() {
             if (self.receipt_queue.length > 0) {
                 var r = self.receipt_queue.shift();
-                self.htmlToImg(r)
+                return self.htmlToImg(r)
                     .then(self.send_printing_job.bind(self))
                     .then(self._onIoTActionResult.bind(self))
                     .then(process_next_job)
                     .guardedCatch(self._onIoTActionFail.bind(self));
             }
         }
-        process_next_job();
+        return process_next_job();
     },
 
     /**
diff --git a/addons/pos_restaurant/static/src/js/multiprint.js b/addons/pos_restaurant/static/src/js/multiprint.js
index cfc59661a71..d284917b940 100644
--- a/addons/pos_restaurant/static/src/js/multiprint.js
+++ b/addons/pos_restaurant/static/src/js/multiprint.js
@@ -297,13 +297,13 @@ models.Order = models.Order.extend({
         };
 
     },
-    printChanges: function(){
+    printChanges: async function(){
         var printers = this.pos.printers;
         for(var i = 0; i < printers.length; i++){
             var changes = this.computeChanges(printers[i].config.product_categories_ids);
             if ( changes['new'].length > 0 || changes['cancelled'].length > 0){
                 var receipt = QWeb.render('OrderChangeReceipt',{changes:changes, widget:this});
-                printers[i].print_receipt(receipt);
+                await printers[i].print_receipt(receipt);
             }
         }
     },
@@ -339,10 +339,10 @@ models.Order = models.Order.extend({
 
 var SubmitOrderButton = screens.ActionButtonWidget.extend({
     'template': 'SubmitOrderButton',
-    button_click: function(){
+    button_click: async function(){
         var order = this.pos.get_order();
         if(order.hasChangesToPrint()){
-            order.printChanges();
+            await order.printChanges();
             order.saveChanges();
         }
     },