[FIX] web: undefined group name for group by date:<interval>

Previously, grouping a list by a non-default time interval (e.g.
'creation date:week') yielded a grouped list of records with undefined
group names.

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

@@ -84,8 +84,8 @@ odoo.define('web.BasicModel', function (require) {
 
 var AbstractModel = require('web.AbstractModel');
 var concurrency = require('web.concurrency');
-var core = require('web.core');
 var Context = require('web.Context');
+var core = require('web.core');
 var Domain = require('web.Domain');
 var fieldUtils = require('web.field_utils');
 var session = require('web.session');
@@ -3087,7 +3087,8 @@ var BasicModel = AbstractModel.extend({
                 lazy: true,
             })
             .then(function (groups) {
-                var rawGroupBy = list.groupedBy[0].split(':')[0];
+                var groupByField = list.groupedBy[0];
+                var rawGroupBy = groupByField.split(':')[0];
                 var previousGroups = _.map(list.data, function (groupID) {
                     return self.localData[groupID];
                 });
@@ -3098,13 +3099,13 @@ var BasicModel = AbstractModel.extend({
                 _.each(groups, function (group) {
                     var aggregateValues = {};
                     _.each(group, function (value, key) {
-                        if (_.contains(fields, key) && key !== list.groupedBy[0]) {
+                        if (_.contains(fields, key) && key !== groupByField) {
                             aggregateValues[key] = value;
                         }
                     });
                     // When a view is grouped, we need to display the name of each group in
                     // the 'title'.
-                    var value = group[rawGroupBy];
+                    var value = group[groupByField];
                     if (list.fields[rawGroupBy].type === "selection") {
                         var choice = _.find(list.fields[rawGroupBy].selection, function (c) {
                             return c[0] === value;

addons/web/static/src/js/views/list/list_renderer.js

@@ -377,6 +377,10 @@ var ListRenderer = BasicRenderer.extend({
             $cells.unshift($('<td>'));
         }
         var name = group.value === undefined ? _t('Undefined') : group.value;
+        var groupBy = this.state.groupedBy[groupLevel];
+        if (group.fields[groupBy.split(':')[0]].type !== 'boolean') {
+            name = name || _t('Undefined');
+        }
         var $th = $('<th>')
                     .addClass('o_group_name')
                     .text(name + ' (' + group.count + ')');

addons/web/static/tests/helpers/mock_server.js

@@ -632,7 +632,9 @@ var MockServer = Class.extend({
             var fieldName = groupByField.split(':')[0];
             var aggregateFunction = groupByField.split(':')[1] || 'month';
             if (fields[fieldName].type === 'date') {
-                if (aggregateFunction === 'day') {
+                if (!val) {
+                    return false;
+                } else if (aggregateFunction === 'day') {
                     return moment(val).format('YYYY-MM-DD');
                 } else {
                     return moment(val).format('MMMM YYYY');

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

@@ -2466,6 +2466,23 @@ QUnit.module('Views', {
 
         list.destroy();
     });
+
+    QUnit.test('list grouped by date:month', function (assert) {
+        assert.expect(1);
+
+        var list = createView({
+            View: ListView,
+            model: 'foo',
+            data: this.data,
+            arch: '<tree><field name="date"/></tree>',
+            groupBy: ['date:month'],
+        });
+
+        assert.strictEqual(list.$('tbody').text(), "January 2017 (1)Undefined (3)",
+            "the group names should be correct");
+
+        list.destroy();
+    });
 });
 
 });