[FIX] web: fields with many2many_tags widget have "default" as view type

When we load a field data with many2many_tags widget, there is no views in the
field info but instead we need to fetch the default fields,
e.g. color, display name and id.

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

@@ -81,8 +81,10 @@ var BasicView = AbstractView.extend({
                         if (!('fieldsInfo' in record.data[name])) {
                             fieldNames.push(name);
                         } else {
+                            var fieldInfo = record.fieldsInfo[viewType][name];
+                            var fieldViews = fieldInfo.views || fieldInfo.fieldsInfo || {};
+                            var fieldViewTypes = Object.keys(fieldViews);
                             var recordViewTypes = Object.keys(record.data[name].fieldsInfo);
-                            var fieldViewTypes = Object.keys(record.fieldsInfo[viewType][name].views);
                             if (_.difference(fieldViewTypes, recordViewTypes).length) {
                                 fieldNames.push(name);
                             }

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

@@ -3402,5 +3402,53 @@ QUnit.module('Views', {
         form.destroy();
     });
 
+    QUnit.test('open one2many form containing many2many_tags', function (assert) {
+            assert.expect(4);
+
+            this.data.partner.records[0].product_ids = [37];
+            this.data.product.fields.partner_type_ids = {
+                string: "many2many partner_type", type: "many2many", relation: "partner_type",
+            };
+            this.data.product.records[0].partner_type_ids = [12, 14];
+
+            var form = createView({
+                View: FormView,
+                model: 'partner',
+                res_id: 1,
+                data: this.data,
+                arch: '<form string="Partners">' +
+                        '<sheet>' +
+                            '<group>' +
+                                '<field name="product_ids">' +
+                                    '<tree create="0">' +
+                                        '<field name="display_name"/>' +
+                                        '<field name="partner_type_ids" widget="many2many_tags"/>' +
+                                    '</tree>' +
+                                    '<form string="Products">' +
+                                        '<sheet>' +
+                                            '<group>' +
+                                                '<label for="partner_type_ids"/>' +
+                                                '<div>' +
+                                                    '<field name="partner_type_ids" widget="many2many_tags"/>' +
+                                                '</div>' +
+                                            '</group>' +
+                                        '</sheet>' +
+                                    '</form>' +
+                                '</field>' +
+                            '</group>' +
+                        '</sheet>' +
+                    '</form>',
+                mockRPC: function (route, args) {
+                    assert.step(args.method);
+                    return this._super.apply(this, arguments);
+                },
+            });
+            var row = form.$('.o_form_field_one2many .o_list_view .o_data_row');
+            row.click();
+            assert.verifySteps(['read', 'read', 'read'],
+                "there should be 3 read rpcs");
+            form.destroy();
+        });
+
 });
 });