[FIX] web: Basic model X2Many commands don't handled correctly

Steps to reproduce:

1. Go to the Accounting / Invoicing apps
2. Open Taxes (Configuration -> Accounting / Invoicing -> Taxes)
3. Try to create a new tax and the client crash.

It occurs because the `_processX2ManyCommands()` method doesn't handle
correctly a missing `fieldInfo` on some X2Many tags.

On mobile, when calling `load_views` the kanban view is used by default.
But if the kanban isn't defined, a default kanban view with only the id
of the model is used.

In the case of the taxes form, the `default_get` retrieved for this
form refers to a Many2Many (`tag_ids`) inside a One2Many. But this field
isn't present inside the loaded kanban view, so when we process the
command defined by the `default_get`, the `field_view` item doesn't
exist (because the default kanban loaded only contains the id of the
field).

Now instead of using an undefined `fieldInfo`, we fall back to an empty
object on the missing field to avoid the crash.

closes odoo/odoo#40617

X-original-commit: 47a306a31ac6d3c9e68e83b77a80426d5c6ceb05
Signed-off-by: res-odoo <res-odoo@users.noreply.github.com>

2 files changed, 56 insertions, 2 deletions

diff --git a/addons/web/static/src/js/views/basic/basic_model.js b/addons/web/static/src/js/views/basic/basic_model.js
index d4e966440cb..3ab3d7f5fa1 100644
--- a/addons/web/static/src/js/views/basic/basic_model.js
+++ b/addons/web/static/src/js/views/basic/basic_model.js
@@ -4227,7 +4227,7 @@ var BasicModel = AbstractModel.extend({
         options = options || {};
         var defs = [];
         var field = record.fields[fieldName];
-        var fieldInfo = record.fieldsInfo[options.viewType || record.viewType][fieldName];
+        var fieldInfo = record.fieldsInfo[options.viewType || record.viewType][fieldName] || {};
         var view = fieldInfo.views && fieldInfo.views[fieldInfo.mode];
         var fieldsInfo = view ? view.fieldsInfo : fieldInfo.fieldsInfo;
         var fields = view ? view.fields : fieldInfo.relatedFields;
diff --git a/addons/web/static/tests/views/basic_model_tests.js b/addons/web/static/tests/views/basic_model_tests.js
index 3f5fca59c60..492f90c4bc8 100644
--- a/addons/web/static/tests/views/basic_model_tests.js
+++ b/addons/web/static/tests/views/basic_model_tests.js
@@ -2,9 +2,11 @@ odoo.define('web.basic_model_tests', function (require) {
     "use strict";
 
     var BasicModel = require('web.BasicModel');
+    var FormView = require('web.FormView');
     var testUtils = require('web.test_utils');
 
     var createModel = testUtils.createModel;
+    var createView = testUtils.createView;
 
     QUnit.module('Views', {
         beforeEach: function () {
@@ -30,7 +32,8 @@ odoo.define('web.basic_model_tests', function (require) {
                 },
                 product: {
                     fields: {
-                        name: { string: "Product Name", type: "char" }
+                        name: { string: "Product Name", type: "char" },
+                        category: { string: "Category M2M", type: 'many2many', relation: 'partner_type' },
                     },
                     records: [
                         { id: 37, display_name: "xphone" },
@@ -62,6 +65,57 @@ odoo.define('web.basic_model_tests', function (require) {
     }, function () {
         QUnit.module('BasicModel');
 
+        QUnit.test('can process x2many commands', async function (assert) {
+            assert.expect(5);
+
+            const form = await createView({
+                View: FormView,
+                model: 'partner',
+                data: this.data,
+                arch: `
+                    <form>
+                        <field name="product_ids"/>
+                    </form>
+                `,
+                archs: {
+                    'product,false,list': `
+                        <tree>
+                            <field name="display_name"/>
+                        </tree>
+                    `,
+                    'product,false,kanban': `
+                        <kanban>
+                            <templates><t t-name="kanban-box">
+                                <div><field name="display_name"/></div>
+                            </t></templates>
+                        </kanban>
+                    `,
+                },
+                viewOptions: {
+                    mode: 'edit',
+                },
+                mockRPC(route, args) {
+                    assert.step(args.method);
+                    if (args.method === 'default_get' && args.model === 'partner') {
+                        return Promise.resolve({
+                            product_ids: [
+                                [0, 0, {category: []}],
+                            ]
+                        });
+                    }
+                    return this._super.apply(this, arguments);
+                },
+            });
+
+            assert.verifySteps([
+                'load_views',
+                'default_get',
+            ]);
+            assert.containsOnce(form, '.o_field_x2many_list', 'should have rendered a x2many list');
+            assert.containsOnce(form, '.o_field_x2many_list_row_add', 'should have rendered a x2many add row on list');
+            form.destroy();
+        });
+
         QUnit.test('can load a record', async function (assert) {
             assert.expect(7);