async support check mode (#82901)

Allow async tasks to run in check mode
Add check_mode support to async_status
Add tests, also for 'hidden' async mode in gather_facts/parallel

changelogs/fragments/async_status_check_mode.yml

@@ -0,0 +1,3 @@
+minor_changes:
+  - async tasks can now also support check mode at the same time.
+  - async_status now supports check mode.

lib/ansible/modules/async_status.py

@@ -36,7 +36,8 @@ attributes:
     async:
         support: none
     check_mode:
-        support: none
+        support: full
+        version_added: '2.17'
     diff_mode:
         support: none
     bypass_host_loop:
@@ -116,12 +117,15 @@ from ansible.module_utils.common.text.converters import to_native
 
 def main():
 
-    module = AnsibleModule(argument_spec=dict(
-        jid=dict(type='str', required=True),
-        mode=dict(type='str', default='status', choices=['cleanup', 'status']),
-        # passed in from the async_status action plugin
-        _async_dir=dict(type='path', required=True),
-    ))
+    module = AnsibleModule(
+        argument_spec=dict(
+            jid=dict(type="str", required=True),
+            mode=dict(type="str", default="status", choices=["cleanup", "status"]),
+            # passed in from the async_status action plugin
+            _async_dir=dict(type="path", required=True),
+        ),
+        supports_check_mode=True,
+    )
 
     mode = module.params['mode']
     jid = module.params['jid']

lib/ansible/plugins/action/__init__.py

@@ -118,8 +118,6 @@ class ActionBase(ABC):
             raise AnsibleActionFail('This action (%s) does not support async.' % self._task.action)
         elif self._task.check_mode and not self._supports_check_mode:
             raise AnsibleActionSkip('This action (%s) does not support check mode.' % self._task.action)
-        elif self._task.async_val and self._task.check_mode:
-            raise AnsibleActionFail('"check mode" and "async" cannot be used on same task.')
 
         # Error if invalid argument is passed
         if self._VALID_ARGS:

test/integration/targets/async/tasks/main.yml

@@ -310,3 +310,30 @@
 - assert:
     that:
     - '"ASYNC OK on localhost" in check_task_disabled_output.stdout'
+
+- name: test 'hidden' async, gather_facts does internal on parallel true. Ensure it won't freeze in check_mode due to async_status not supporting it.
+  gather_facts:
+    parallel: true
+  timeout: 60
+  check_mode: true
+  when: "ansible_facts['os_family'] != 'Darwin'"
+  vars:
+    ansible_facts_modules:
+      - setup
+      - package_facts
+      - service_facts
+
+- name: test async in check mode
+  check_mode: true
+  block:
+    - setup:
+      async: 60
+      poll: 0
+      register: gf_async
+    - async_status:
+        jid: "{{ gf_async['ansible_job_id'] }}"
+      register: gf_done
+      until: gf_done is finished
+      retries: 100
+      delay: 10
+      timeout: 30