fixed issue with default callback inheritance (#30427)

* fixed issue with default callback inheritance

 - callbacks need to document same options as callbacks they inherit from to get them configured
 - since default is also used by many 3rd party callbacks for inheritance, making the code 'tolerate' the missing docs
   and fallback to using the direct constant to configure it's options.

lib/ansible/plugins/callback/default.py

@@ -12,27 +12,8 @@ DOCUMENTATION = '''
     version_added: historical
     description:
         - This is the default output callback for ansible-playbook.
-    options:
-      show_skipped_hosts:
-        name: Show skipped hosts
-        description: "Toggle to control displaying skipped task/host results in a task"
-        default: True
-        env:
-          - name: DISPLAY_SKIPPED_HOSTS
-        ini:
-          - key: display_skipped_hosts
-            section: defaults
-        type: boolean
-      show_custom_stats:
-        name: Show custom stats
-        description: 'This adds the custom stats set via the set_stats plugin to the play recap'
-        default: False
-        env:
-          - name: ANSIBLE_SHOW_CUSTOM_STATS
-        ini:
-          - key: show_custom_stats
-            section: defaults
-        type: bool
+    extends_documentation_fragment:
+      - default_callback
     requirements:
       - set as stdout in configuration
 '''
@@ -118,9 +99,8 @@ class CallbackModule(CallbackBase):
             self._display.display(msg, color=color)
 
     def v2_runner_on_skipped(self, result):
-        if self._plugin_options['show_skipped_hosts']:
+        if self._plugin_options.get('show_skipped_hosts', C.DISPLAY_SKIPPED_HOSTS):  # fallback on constants for inherited plugins missing docs
 
-            delegated_vars = result._result.get('_ansible_delegated_vars', None)
             self._clean_results(result._result, result._task.action)
 
             if self._play.strategy == 'free' and self._last_task_banner != result._task._uuid:
@@ -247,7 +227,7 @@ class CallbackModule(CallbackBase):
         self._display.display(msg + " (item=%s) => %s" % (self._get_item(result._result), self._dump_results(result._result)), color=C.COLOR_ERROR)
 
     def v2_runner_item_on_skipped(self, result):
-        if self._plugin_options['show_skipped_hosts']:
+        if self._plugin_options.get('show_skipped_hosts', C.DISPLAY_SKIPPED_HOSTS):  # fallback on constants for inherited plugins missing docs
             self._clean_results(result._result, result._task.action)
             msg = "skipping: [%s] => (item=%s) " % (result._host.get_name(), self._get_item(result._result))
             if (self._display.verbosity > 0 or '_ansible_verbose_always' in result._result) and '_ansible_verbose_override' not in result._result:
@@ -286,7 +266,7 @@ class CallbackModule(CallbackBase):
         self._display.display("", screen_only=True)
 
         # print custom stats
-        if self._plugin_options['show_custom_stats'] and stats.custom:
+        if self._plugin_options.get('show_custom_stats', C.SHOW_CUSTOM_STATS) and stats.custom:  # fallback on constants for inherited plugins missing docs
             self._display.banner("CUSTOM STATS: ")
             # per host
             # TODO: come up with 'pretty format'
@@ -307,11 +287,12 @@ class CallbackModule(CallbackBase):
             self._display.banner("PLAYBOOK: %s" % basename(playbook._file_name))
 
         if self._display.verbosity > 3:
-            if self._plugin_options is not None:
-                for option in dir(self._plugin_options):
+            # show CLI options
+            if self._options is not None:
+                for option in dir(self._options):
                     if option.startswith('_') or option in ['read_file', 'ensure_value', 'read_module']:
                         continue
-                    val = getattr(self._plugin_options, option)
+                    val = getattr(self._options, option)
                     if val:
                         self._display.vvvv('%s: %s' % (option, val))