[FIX] web: generate proper x2many commands in some cases

When creating a new record with a non empty default value for a one2many
field, we did send the command 0 (for each one2many line) instead of the
command 1 (update).  This was a pretty big problem, because then the
server would try to create a line with possibly incomplete data.

For example, it was not possible to create expense sheets: go to expense
menu, select one expense in the list view, click on the action menu
'submit to manager', this opens a form view with a one2many with the
selected expense, then save.  Before this commit, this would lead to a
server error.

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

@@ -875,7 +875,10 @@ var BasicModel = AbstractModel.extend({
                 // id never changes, and should not be written
                 delete record._changes.id;
             }
-            var changes = self._generateChanges(record, {viewType: options.viewType});
+            var changes = self._generateChanges(record, {viewType: options.viewType, changesOnly: method !== 'create'});
+
+            // id field should never be written/changed
+            delete changes.id;
 
             if (method === 'create') {
                 var fieldNames = record.getFieldNames();
@@ -2438,7 +2441,7 @@ var BasicModel = AbstractModel.extend({
             changes = _.extend({}, record.data, record._changes);
         } else {
             changes = _.extend({}, record._changes);
-        };
+        }
         var withReadonly = options.withReadonly || false;
         var commands = this._generateX2ManyCommands(record, {
             changesOnly: 'changesOnly' in options ? options.changesOnly : true,
@@ -2475,6 +2478,7 @@ var BasicModel = AbstractModel.extend({
                 changes[fieldName] = false;
             }
         }
+
         return changes;
     },
     /**
@@ -2621,7 +2625,13 @@ var BasicModel = AbstractModel.extend({
                             // this is a new id
                             relRecord = _.findWhere(relRecordAdded, {res_id: list.res_ids[i]});
                             changes = this._generateChanges(relRecord, options);
-                            commands[fieldName].push(x2ManyCommands.create(changes));
+                            if ('id' in changes) {
+                                var id = changes.id;
+                                delete changes.id;
+                                commands[fieldName].push(x2ManyCommands.update(id, changes));
+                            } else {
+                                commands[fieldName].push(x2ManyCommands.create(changes));
+                            }
                         }
                     }
                     if (options.changesOnly && !didChange && addedIds.length === 0 && removedIds.length === 0) {

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

@@ -1062,14 +1062,14 @@ QUnit.module('relational_fields', {
     });
 
     QUnit.test('list in form: default_get with x2many create and onchange', function (assert) {
-        assert.expect(1);
+        assert.expect(2);
 
         this.data.partner.onchanges.turtles = function (obj) {
             assert.deepEqual(
                 obj.turtles,
                 [
-                    [0, false, {turtle_foo: 'blip', id: 2}],
-                    [0, false, {turtle_foo: 'kawa', id: 3}]
+                    [1, 2, {turtle_foo: 'blip'}],
+                    [1, 3, {turtle_foo: 'kawa'}]
                 ],
                 "should have properly created the x2many command list");
         };
@@ -1092,10 +1092,21 @@ QUnit.module('relational_fields', {
                 if (args.method === 'default_get') {
                     return $.when({turtles: [[6, 0, [2,3]]]});
                 }
+                if (args.method === 'create') {
+                    // it would be even better if we did not send the current
+                    // unchanged state with the command 1, but this seems more
+                    // difficult.
+                    assert.deepEqual(args.args[0].turtles, [
+                        [1, 2, {turtle_foo: 'blip'}],
+                        [1, 3, {turtle_foo: 'kawa'}]
+                    ], 'should send proper commands to create method');
+                }
                 return this._super.apply(this, arguments);
             },
         });
 
+        form.$buttons.find('.o_form_button_save').click();
+
         form.destroy();
     });