avoid fatal tb on bad fqcn callback name (#69440) (#69496)

(cherry picked from commit 0aa76503dc)

changelogs/fragments/no_fatal_bad_cb.yml

@@ -0,0 +1,2 @@
+bugfixes:
+    - avoid fatal traceback when a bad FQCN for a callback is supplied in the whitelist (#69401).

lib/ansible/executor/task_queue_manager.py

@@ -161,8 +161,11 @@ class TaskQueueManager:
         for callback_plugin_name in (c for c in C.DEFAULT_CALLBACK_WHITELIST if AnsibleCollectionRef.is_valid_fqcr(c)):
             # TODO: need to extend/duplicate the stdout callback check here (and possible move this ahead of the old way
             callback_obj = callback_loader.get(callback_plugin_name)
-            callback_obj.set_options()
-            self._callback_plugins.append(callback_obj)
+            if callback_obj:
+                callback_obj.set_options()
+                self._callback_plugins.append(callback_obj)
+            else:
+                display.warning("Skipping '%s', unable to load or use as a callback" % callback_plugin_name)
 
         self._callbacks_loaded = True
 

test/integration/targets/collections/runme.sh

@@ -42,3 +42,6 @@ ansible-playbook -i "${INVENTORY_PATH}"  -i ./a.statichost.yml -v "${TEST_PLAYBO
 # test adjacent with --playbook-dir
 export ANSIBLE_COLLECTIONS_PATHS=''
 ANSIBLE_INVENTORY_ANY_UNPARSED_IS_FAILED=1 ansible-inventory -i a.statichost.yml --list --export --playbook-dir=. -v "$@"
+
+# ensure non existing callback does not crash ansible
+ANSIBLE_CALLBACK_WHITELIST=charlie.gomez.notme ansible -m ping localhost