Fix run_once by instantly tiny post_validate (#78492) (#80051)

Signed-off-by: tu1h <lihai.tu@daocloud.io>

changelogs/fragments/78492-fix-invalid-run_once-value.yml

@@ -0,0 +1,3 @@
+---
+bugfixes:
+  - "strategy plugins: get the correctly templated and validated run_once value on strategy linear (https://github.com/ansible/ansible/issues/78492)"

lib/ansible/plugins/strategy/linear.py

@@ -35,6 +35,7 @@ from ansible import constants as C
 from ansible.errors import AnsibleError, AnsibleAssertionError, AnsibleParserError
 from ansible.executor.play_iterator import IteratingStates, FailedStates
 from ansible.module_utils._text import to_text
+from ansible.module_utils.parsing.convert_bool import boolean
 from ansible.playbook.handler import Handler
 from ansible.playbook.included_file import IncludedFile
 from ansible.playbook.task import Task
@@ -213,7 +214,10 @@ class StrategyModule(StrategyBase):
                                 skip_rest = True
                                 break
 
-                        run_once = templar.template(task.run_once) or action and getattr(action, 'BYPASS_HOST_LOOP', False)
+                        if templar.is_template(task.run_once):
+                            setattr(task, 'run_once', boolean(templar.template(task.run_once), strict=True))
+
+                        run_once = task.run_once or action and getattr(action, 'BYPASS_HOST_LOOP', False)
 
                         if (task.any_errors_fatal or run_once) and not task.ignore_errors:
                             any_errors_fatal = True

test/integration/targets/strategy_linear/runme.sh

@@ -5,3 +5,5 @@ set -eux
 ansible-playbook test_include_file_noop.yml -i inventory "$@"
 
 ansible-playbook task_action_templating.yml -i inventory "$@"
+
+ansible-playbook task_templated_run_once.yml -i inventory "$@"

test/integration/targets/strategy_linear/task_templated_run_once.yml

@@ -0,0 +1,20 @@
+- hosts: testhost,testhost2
+  gather_facts: no
+  vars:
+    run_once_flag: false
+  tasks:
+    - debug:
+        msg: "I am {{ item }}"
+      run_once: "{{ run_once_flag }}"
+      register: reg1
+      loop:
+        - "{{ inventory_hostname }}"
+
+    - assert:
+        that:
+          - "reg1.results[0].msg == 'I am testhost'"
+      when: inventory_hostname == 'testhost'
+    - assert:
+        that:
+          - "reg1.results[0].msg == 'I am testhost2'"
+      when: inventory_hostname == 'testhost2'