don't assume all delegation subkeys exist (#43032)

* don't assume all delegation subkeys exist

fixes #43026

* add tests

lib/ansible/executor/task_result.py

@@ -126,7 +126,8 @@ class TaskResult:
                 if sub in self._result:
                     x[sub] = {}
                     for key in _SUB_PRESERVE[sub]:
-                        x[sub][key] = self._result[sub][key]
+                        if key in self._result[sub]:
+                            x[sub][key] = self._result[sub][key]
 
             result._result = x
         elif self._result:

test/integration/targets/delegate_to/delegate_and_nolog.yml

@@ -0,0 +1,8 @@
+- hosts: testhost
+  gather_facts: false
+  tasks:
+    - name: no log filtering caused delegation to fail https://github.com/ansible/ansible/issues/43026
+      become: False
+      no_log: true
+      debug:
+      delegate_to: localhost

test/integration/targets/delegate_to/runme.sh

@@ -8,3 +8,5 @@ ANSIBLE_SSH_ARGS='-C -o ControlMaster=auto -o ControlPersist=60s -o UserKnownHos
 ansible-playbook test_loop_control.yml -v "$@"
 
 ansible-playbook test_delegate_to_loop_randomness.yml -v "$@"
+
+ansible-playbook delegate_and_nolog.yml -v "$@"