1 files changed, 8 insertions, 3 deletions
diff --git a/addons/web/static/src/js/views/basic/basic_controller.js b/addons/web/static/src/js/views/basic/basic_controller.js
index 767a6511ce3..43d604eac0b 100644
--- a/addons/web/static/src/js/views/basic/basic_controller.js
+++ b/addons/web/static/src/js/views/basic/basic_controller.js
@@ -173,15 +173,20 @@ var BasicController = AbstractController.extend(FieldManagerMixin, {
         // may have to validate them before notifying them, so we ask them to
         // commit their current value before saving. This has to be done outside
         // of the mutex protection of saving because commitChanges will trigger
-        // changes and these are also protected. So the actual saving has to be
+        // changes and these are also protected. However, we must wait for the
+        // mutex to be idle to ensure that onchange RPCs returned before asking
+        // field widgets to commit their value (and validate it, for instance
+        // for one2many with required fields). So the actual saving has to be
         // done after these changes. Also the commitChanges operation might not
         // be synchronous for other reason (e.g. the x2m fields will ask the
         // user if some discarding has to be made). This operation must also be
         // mutex-protected as commitChanges function of x2m has to be aware of
         // all final changes made to a row.
         var self = this;
-        return this.renderer.commitChanges(recordID || this.handle).then(function () {
-            return self.mutex.exec(self._saveRecord.bind(self, recordID, options));
+        return this.mutex.getUnlockedDef().then(function () {
+            return self.renderer.commitChanges(recordID || self.handle).then(function () {
+                return self.mutex.exec(self._saveRecord.bind(self, recordID, options));
+            });
         });
     },
     /**