add per item diff handling

fixes #14843

lib/ansible/executor/process/result.py

@@ -115,6 +115,8 @@ class ResultProcess(multiprocessing.Process):
                         self._send_result(('v2_playbook_item_on_skipped', result))
                     else:
                         self._send_result(('v2_playbook_item_on_ok', result))
+                        if 'diff' in result._result:
+                            self._send_result(('v2_on_file_diff', result))
                     continue
 
                 clean_copy = strip_internal_keys(result._result)

lib/ansible/plugins/strategy/__init__.py

@@ -331,6 +331,9 @@ class StrategyBase:
                                 self._variable_manager.set_host_facts(target_host, facts)
                 elif result[0].startswith('v2_playbook_item') or result[0] == 'v2_playbook_retry':
                     self._tqm.send_callback(result[0], result[1])
+                elif result[0] == 'v2_on_file_diff':
+                    if self._diff:
+                        self._tqm.send_callback('v2_on_file_diff', result[1])
                 else:
                     raise AnsibleError("unknown result message received: %s" % result[0])