[FIX] web: FieldMany2Many: don't save if nothing changed

Suppose that there is a many2many list (non editable) in a form
view. When one of the many2many subrecords is edited (from the
form view in a dialog), it is saved directly when the user clicks
on 'Save' in the dialog.

Before this rev., if the user clicked on 'Save' in the main form
view after editing a m2m subrecord, a 'write' RPC was done, whereas
there were nothing left to save (as the subrecord had already been
saved).

1 files changed, 8 insertions, 0 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 11961e6fecf..595c39103d3 100644
--- a/addons/web/static/src/js/views/basic/basic_model.js
+++ b/addons/web/static/src/js/views/basic/basic_model.js
@@ -1117,6 +1117,14 @@ var BasicModel = AbstractModel.extend({
      * @returns {Deferred}
      */
     _applyX2ManyChange: function (record, fieldName, command, viewType) {
+        if (command.operation === 'TRIGGER_ONCHANGE') {
+            // the purpose of this operation is to trigger an onchange RPC, so
+            // there is no need to apply any change on the record (the changes
+            // have probably been already applied and saved, usecase: many2many
+            // edition in a dialog)
+            return $.when();
+        }
+
         var self = this;
         var list = this.localData[record._changes[fieldName] || record.data[fieldName]];
         var field = record.fields[fieldName];