[FIX] web: nested x2many with non inline views

Let's assume a form view with an x2many list, containing itself
an x2many field (no widget, so simply displaying the number of
records). When a record of the list is clicked, a form view
opens and displays the same sub x2many field, with widget
many2many_tags. Both list and form views of the x2many aren't
inline (thus have to be fetched on demand).

Before this commit, it crashed when the user clicked on a row
of the x2many list.

The bug has been introduced by a9cebd5a, which wrongly removed the
code handling this specific situation. At least, now we have a
test attesting that this code isn't useless.

Note that the diff isn't as scary as it looks like (we just added
an if/else, and thus indented the former code inside the else
clause).

closes odoo/odoo#48116

Signed-off-by: Géry Debongnie (ged) <ged@openerp.com>

2 files changed, 52 insertions, 20 deletions

diff --git a/addons/web/static/src/js/views/basic/basic_view.js b/addons/web/static/src/js/views/basic/basic_view.js
index 6668392b823..140c338d6f6 100644
--- a/addons/web/static/src/js/views/basic/basic_view.js
+++ b/addons/web/static/src/js/views/basic/basic_view.js
@@ -138,28 +138,32 @@ var BasicView = AbstractView.extend({
                     // X2Many case: field is an x2many displayed as a list or
                     // kanban view, but the related fields haven't been loaded yet.
                     if ((fieldType === 'one2many' || fieldType === 'many2many')) {
-                        var x2mFieldInfo = record.fieldsInfo[this.viewType][name];
-                        var viewType = x2mFieldInfo.viewType || x2mFieldInfo.mode;
-                        var knownFields = Object.keys(record.data[name].fieldsInfo[record.data[name].viewType] || {});
-                        var newFields = Object.keys(record.data[name].fieldsInfo[viewType]);
-                        if (_.difference(newFields, knownFields).length) {
+                        if (!('fieldsInfo' in record.data[name])) {
                             fieldNames.push(name);
-                        }
-
-                        if (record.data[name].viewType === 'default') {
-                            // Use case: x2many (tags) in x2many list views
-                            // When opening the x2many record form view, the
-                            // x2many will be reloaded but it may not have
-                            // the same fields (ex: tags in list and list in
-                            // form) so we need to merge the fieldsInfo to
-                            // avoid losing the initial fields (display_name)
-                            var fieldViews = fieldInfo.views || fieldInfo.fieldsInfo || {};
-                            var defaultFieldInfo = record.data[name].fieldsInfo.default;
-                            _.each(fieldViews, function (fieldView) {
-                                _.each(fieldView.fieldsInfo, function (x2mFieldInfo) {
-                                    _.defaults(x2mFieldInfo, defaultFieldInfo);
+                        } else {
+                            var x2mFieldInfo = record.fieldsInfo[this.viewType][name];
+                            var viewType = x2mFieldInfo.viewType || x2mFieldInfo.mode;
+                            var knownFields = Object.keys(record.data[name].fieldsInfo[record.data[name].viewType] || {});
+                            var newFields = Object.keys(record.data[name].fieldsInfo[viewType]);
+                            if (_.difference(newFields, knownFields).length) {
+                                fieldNames.push(name);
+                            }
+
+                            if (record.data[name].viewType === 'default') {
+                                // Use case: x2many (tags) in x2many list views
+                                // When opening the x2many record form view, the
+                                // x2many will be reloaded but it may not have
+                                // the same fields (ex: tags in list and list in
+                                // form) so we need to merge the fieldsInfo to
+                                // avoid losing the initial fields (display_name)
+                                var fieldViews = fieldInfo.views || fieldInfo.fieldsInfo || {};
+                                var defaultFieldInfo = record.data[name].fieldsInfo.default;
+                                _.each(fieldViews, function (fieldView) {
+                                    _.each(fieldView.fieldsInfo, function (x2mFieldInfo) {
+                                        _.defaults(x2mFieldInfo, defaultFieldInfo);
+                                    });
                                 });
-                            });
+                            }
                         }
                     }
                     // Many2one: context is not the same between the different views
diff --git a/addons/web/static/tests/fields/relational_fields/field_one2many_tests.js b/addons/web/static/tests/fields/relational_fields/field_one2many_tests.js
index e93dc2f39ca..4bd23d0d76b 100644
--- a/addons/web/static/tests/fields/relational_fields/field_one2many_tests.js
+++ b/addons/web/static/tests/fields/relational_fields/field_one2many_tests.js
@@ -5508,6 +5508,34 @@ QUnit.module('fields', {}, function () {
             form.destroy();
         });
 
+        QUnit.test('nested x2many (non inline views and no widget on inner x2many in list)', async function (assert) {
+            assert.expect(5);
+
+            this.data.partner.records[0].p = [1];
+            const form = await createView({
+                View: FormView,
+                model: 'partner',
+                data: this.data,
+                arch: '<form><field name="p"/></form>',
+                archs: {
+                    'partner,false,list': '<tree><field name="turtles"/></tree>',
+                    'partner,false,form': '<form><field name="turtles" widget="many2many_tags"/></form>',
+                },
+                res_id: 1,
+            });
+
+            assert.containsOnce(form, '.o_data_row');
+            assert.strictEqual(form.$('.o_data_row').text(), '1 record');
+
+            await testUtils.dom.click(form.$('.o_data_row'));
+
+            assert.containsOnce(document.body, '.modal .o_form_view');
+            assert.containsOnce(document.body, '.modal .o_form_view .o_field_many2manytags .badge');
+            assert.strictEqual($('.modal .o_field_many2manytags').text().trim(), 'donatello');
+
+            form.destroy();
+        });
+
         QUnit.test('one2many (who contains display_name) with tree view and without form view', async function (assert) {
             assert.expect(1);