[FIX] web: make sure modifiers works for async widgets

Before this commit, asynchronous field widgets (with willStart async),
with a non empty template had a problem: the invisible modifier was not
applied properly.

The reason is that the code that applied the modifiers was called
directly after the widget was 'willStarted'. This means that if this is
async, and if there is a template, the $el in willStart will be replaced
by another $el after, which will remove the invisible modifier.

This was an interesting problem with the pad widget (it is asynchronous
the first time a pad widget is instantiated)

addons/web/static/src/js/views/basic/basic_renderer.js

@@ -484,15 +484,18 @@ var BasicRenderer = AbstractRenderer.extend({
         // Update the modifiers registration by associating the widget and by
         // giving the modifiers options now (as the potential callback is
         // associated to new widget)
-        this._registerModifiers(node, record, widget, _.extend({
-            callback: (function (element, modifiers, record) {
-                element.$el.toggleClass('o_field_empty', !!(
-                    record.data.id
-                    && (modifiers.readonly || this.mode === 'readonly')
-                    && !element.widget.isSet()
-                ));
-            }).bind(this),
-        }, modifiersOptions || {}));
+        var self = this;
+        def.then(function () {
+            self._registerModifiers(node, record, widget, _.extend({
+                callback: function (element, modifiers, record) {
+                    element.$el.toggleClass('o_field_empty', !!(
+                        record.data.id
+                        && (modifiers.readonly || self.mode === 'readonly')
+                        && !element.widget.isSet()
+                    ));
+                },
+            }, modifiersOptions || {}));
+        });
 
         return widget;
     },

addons/web/static/tests/views/form_tests.js

@@ -4,6 +4,7 @@ odoo.define('web.form_tests', function (require) {
 var concurrency = require('web.concurrency');
 var config = require('web.config');
 var core = require('web.core');
+var fieldRegistry = require('web.field_registry');
 var FormView = require('web.FormView');
 var testUtils = require('web.test_utils');
 
@@ -305,6 +306,41 @@ QUnit.module('Views', {
         form.destroy();
     });
 
+    QUnit.test('asynchronous fields can be set invisible', function (assert) {
+        assert.expect(1);
+
+        var def = $.Deferred();
+
+        // we choose this widget because it is a quite simple widget with a non
+        // empty qweb template
+        var PercentPieWidget = fieldRegistry.get('percentpie');
+        fieldRegistry.add('asyncwidget', PercentPieWidget.extend({
+            willStart: function () {
+                return def;
+            },
+        }));
+
+        createAsyncView({
+            View: FormView,
+            model: 'partner',
+            data: this.data,
+            arch: '<form string="Partners">' +
+                    '<sheet><group>' +
+                        '<field name="foo"/>' +
+                        '<field name="int_field" invisible="1" widget="asyncwidget"/>' +
+                    '</group></sheet>' +
+                '</form>',
+            res_id: 1,
+        }).then(function (form) {
+            assert.ok(form.$('.o_field_widget[name="int_field"]').hasClass('o_invisible_modifier'),
+                'int_field is invisible');
+            form.destroy();
+            delete fieldRegistry.map.asyncwidget;
+        });
+        def.resolve();
+    });
+
+
     QUnit.test('properly handle modifiers and attributes on notebook tags', function (assert) {
         assert.expect(2);