[FIX] barcodes: manage several barcode widgets

In some cases, several barcode widgets can be found on the same page.
This is for example the case of the stock picking: there is a widget on
the `stock.picking` model (main view) itself, and a widget on the
`stock.pack.operation` model (modal view).

In this case, when the focus is not set directly on the field which
needs to be filled in, both widgets will trigger a `barcode_scanned`
scanned event. This will call the `on_barcode_scanned` Python method
which can lead to errors/warning. For example, the `on_barcode_scanned`
method on the `stock.picking` model raises a warning in case the barcode
scanned does not match any product/package.

The fix is to make sure that the event target is located in the correct
DOM element.

opw-677506

addons/barcodes/static/src/js/barcode_events.js

@@ -36,7 +36,9 @@ var BarcodeEvents = core.Class.extend(mixins.PropertiesMixin, {
         if (match) {
             var barcode = match[1];
 
-            core.bus.trigger('barcode_scanned', barcode);
+            // Send the target in case there are several barcode widgets on the same page (e.g.
+            // registering the lot numbers in a stock picking)
+            core.bus.trigger('barcode_scanned', barcode, this.buffered_key_events[0].target);
 
             // Dispatch a barcode_scanned DOM event to elements that have barcode_events="true" set.
             if (this.buffered_key_events[0].target.getAttribute("barcode_events") === "true")

addons/barcodes/static/src/js/barcode_handler_mixin.js

@@ -13,8 +13,13 @@ return {
     init: function() {
         var self = this;
         this._super.apply(this, arguments);
-        this.__on_barcode_scanned = function () {
-            self.on_barcode_scanned.apply(self, arguments);
+        this.__on_barcode_scanned = function (barcode, target) {
+            // Handle the case where there are several barcode widgets on the same page. Since the
+            // event is global on the page, all barcode widgets will be triggered. However, we only
+            // want to keep the event on the target widget.
+            if ($.contains(target, self.el)) {
+                self.on_barcode_scanned.call(self, barcode);
+            }
         };
         this.start_listening();
         // Handlers inside a View managed by a ViewManager only listen to barcode events while their view is displayed