[FIX] web: handle x2m commands with reference as default

Before this rev. it was not possible to define a value for a reference field
in x2m commands as default value.

Courtesy of @kaerdsar.

Closes #24070

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

@@ -3613,8 +3613,9 @@ var BasicModel = AbstractModel.extend({
                     if (isFieldInView) {
                         var field = r.fields[fieldName];
                         var fieldType = field.type;
+                        var rec;
                         if (fieldType === 'many2one') {
-                            var rec = self._makeDataPoint({
+                            rec = self._makeDataPoint({
                                 context: r.context,
                                 modelName: field.relation,
                                 data: {id: r._changes[fieldName]},
@@ -3622,6 +3623,16 @@ var BasicModel = AbstractModel.extend({
                             });
                             r._changes[fieldName] = rec.id;
                             many2ones[fieldName] = true;
+                        } else if (fieldType === 'reference') {
+                            var reference = r._changes[fieldName].split(',');
+                            rec = self._makeDataPoint({
+                                context: r.context,
+                                modelName: reference[0],
+                                data: {id: parseInt(reference[1])},
+                                parentID: r.id,
+                            });
+                            r._changes[fieldName] = rec.id;
+                            many2ones[fieldName] = true;
                         } else if (_.contains(['one2many', 'many2many'], fieldType)) {
                             var x2mCommands = commands[0][2][fieldName];
                             defs.push(self._processX2ManyCommands(r, fieldName, x2mCommands));

addons/web/static/tests/fields/relational_fields_tests.js

@@ -11248,6 +11248,38 @@ QUnit.module('relational_fields', {
         form.destroy();
     });
 
+    QUnit.test('default_get a reference field in a x2m', function (assert) {
+        assert.expect(1);
+
+        this.data.partner.fields.turtles.default = [
+            [0, false, {turtle_ref: 'product,37'}]
+        ];
+
+        var form = createView({
+            View: FormView,
+            model: 'partner',
+            data: this.data,
+            arch: '<form string="Partners">' +
+                    '<sheet>' +
+                        '<field name="turtles">' +
+                            '<tree>' +
+                                '<field name="turtle_ref"/>' +
+                            '</tree>' +
+                        '</field>' +
+                    '</sheet>' +
+                '</form>',
+            viewOptions: {
+                mode: 'edit',
+            },
+            archs: {
+                'turtle,false,form': '<form><field name="display_name"/><field name="turtle_ref"/></form>',
+            },
+        });
+        assert.strictEqual(form.$('.o_field_one2many[name="turtles"] .o_data_row:first').text(), "xphone",
+            "the default value should be correctly handled");
+        form.destroy();
+    });
+
     QUnit.test('widget reference on char field, reset by onchange', function (assert) {
         assert.expect(4);