1 files changed, 53 insertions, 0 deletions
diff --git a/addons/web/static/tests/fields/relational_fields_tests.js b/addons/web/static/tests/fields/relational_fields_tests.js
index b79e0d4a660..c82d031d7d5 100644
--- a/addons/web/static/tests/fields/relational_fields_tests.js
+++ b/addons/web/static/tests/fields/relational_fields_tests.js
@@ -8,6 +8,7 @@ var relationalFields = require('web.relational_fields');
 var testUtils = require('web.test_utils');
 
 var createView = testUtils.createView;
+var createAsyncView = testUtils.createAsyncView;
 
 QUnit.module('fields', {}, function () {
 
@@ -677,6 +678,58 @@ QUnit.module('relational_fields', {
         form.destroy();
     });
 
+    // FORWARDPORT THIS UP TO 12.2, NOT FURTHER
+    QUnit.test('many2manys inside a one2many are fetched in batch after onchange', async function (assert) {
+        assert.expect(7);
+
+        this.data.partner.onchanges = {
+            turtles: function (obj) {
+                obj.turtles = [
+                    [5],
+                    [1, 1, {
+                        turtle_foo: "leonardo",
+                        partner_ids: [[4, 2]],
+                    }],
+                    [1, 2, {
+                        turtle_foo: "donatello",
+                        partner_ids: [[4, 2], [4, 4]],
+                    }],
+                ];
+            },
+        };
+
+        var form = await createAsyncView({
+            View: FormView,
+            model: 'partner',
+            data: this.data,
+            arch: '<form>' +
+                        '<field name="turtles">' +
+                            '<tree editable="bottom">' +
+                                '<field name="turtle_foo"/>' +
+                                '<field name="partner_ids" widget="many2many_tags"/>' +
+                            '</tree>' +
+                        '</field>' +
+                    '</form>',
+            enableBasicModelBachedRPCs: true,
+            mockRPC: function (route, args) {
+                assert.step(args.method || route);
+                if (args.method === 'read') {
+                    assert.deepEqual(args.args[0], [2, 4],
+                        'should read the partner_ids once, batched');
+                }
+                return this._super.apply(this, arguments);
+            },
+        });
+
+        assert.containsN(form, '.o_data_row', 2);
+        assert.strictEqual(form.$('.o_field_widget[name="partner_ids"]').text().replace(/\s/g, ''),
+            "secondrecordsecondrecordaaa");
+
+        assert.verifySteps(['default_get', 'onchange', 'read']);
+
+        form.destroy();
+    });
+
     QUnit.test('many2many read, field context is properly sent', function (assert) {
         assert.expect(4);