[FIX] web: do not apply impossible onchanges

Before this commit, all onchanges were applied if the field
was known on the model.

However it's not possible to apply onchanges on x2many not in
the view as we don't know their fieldsInfo.

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

@@ -946,6 +946,9 @@ var BasicModel = AbstractModel.extend({
                     list = self.localData[listId];
                 } else {
                     var fieldInfo = record.fieldsInfo[record.viewType][name];
+                    if (!fieldInfo) {
+                        return; //ignore changes of x2many not in view
+                    }
                     list = self._makeDataPoint({
                         fieldsInfo: fieldInfo.fieldsInfo,
                         modelName: field.relation,

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

@@ -221,6 +221,38 @@ QUnit.module('Views', {
         model.destroy();
     });
 
+    QUnit.test('onchange on a one2many not in view (fieldNames)', function (assert) {
+        assert.expect(6);
+
+        this.data.partner.onchanges.foo = function (obj) {
+            obj.bar = obj.foo.length;
+            obj.product_ids = [];
+        };
+
+        this.params.fieldNames = ['foo'];
+
+        var model = createModel({
+            Model: BasicModel,
+            data: this.data,
+        });
+
+        model.load(this.params).then(function (resultID) {
+            var record = model.get(resultID);
+            assert.strictEqual(record.data.foo, 'gnap', "foo field is properly initialized");
+            assert.strictEqual(record.data.bar, undefined, "bar field is not loaded");
+            assert.strictEqual(record.data.product_ids, undefined, "product_ids field is not loaded");
+
+            model.notifyChanges(resultID, {foo: 'mary poppins'});
+
+            record = model.get(resultID);
+            assert.strictEqual(record.data.foo, 'mary poppins', "onchange has been applied");
+            assert.strictEqual(record.data.bar, 12, "onchange has been applied");
+            assert.strictEqual(record.data.product_ids, undefined,
+                "onchange on product_ids (one2many) has not been applied");
+        });
+        model.destroy();
+    });
+
     QUnit.test('notifyChange on a many2one, without display_name', function (assert) {
         assert.expect(3);