2.9.10: UnboundLocalError: local variable 'module_style' referenced before assignment

[resmo]

SUMMARY

after upgrade from 2.9.9 to 2.9.10 we see an exception in a task using lineinfile delegate_facts=true

ISSUE TYPE

• Bug Report

COMPONENT NAME

ANSIBLE VERSION

2.9.10

CONFIGURATION

ANSIBLE_NOCOWS(/home/rmoser/Projects/puzzle/ansible-puzzle/ansible.cfg) = True
ANSIBLE_PIPELINING(/home/rmoser/Projects/puzzle/ansible-puzzle/ansible.cfg) = True
ANSIBLE_SSH_ARGS(/home/rmoser/Projects/puzzle/ansible-puzzle/ansible.cfg) = -o ControlMaster=auto -o ControlPersist=60s -o UserKnownHostsFile=/dev/null -o StrictHostKeyChecking=no
CACHE_PLUGIN(/home/rmoser/Projects/puzzle/ansible-puzzle/ansible.cfg) = jsonfile
CACHE_PLUGIN_CONNECTION(/home/rmoser/Projects/puzzle/ansible-puzzle/ansible.cfg) = .cache/facts
CACHE_PLUGIN_TIMEOUT(/home/rmoser/Projects/puzzle/ansible-puzzle/ansible.cfg) = 86400
COLLECTIONS_PATHS(/home/rmoser/Projects/puzzle/ansible-puzzle/ansible.cfg) = [u'/home/rmoser/Projects/puzzle/ansible-puzzle/collections_galaxy']
CONDITIONAL_BARE_VARS(/home/rmoser/Projects/puzzle/ansible-puzzle/ansible.cfg) = False
DEFAULT_BECOME(/home/rmoser/Projects/puzzle/ansible-puzzle/ansible.cfg) = True
DEFAULT_BECOME_ASK_PASS(/home/rmoser/Projects/puzzle/ansible-puzzle/ansible.cfg) = False
DEFAULT_BECOME_METHOD(/home/rmoser/Projects/puzzle/ansible-puzzle/ansible.cfg) = sudo
DEFAULT_BECOME_USER(/home/rmoser/Projects/puzzle/ansible-puzzle/ansible.cfg) = root
DEFAULT_FORKS(/home/rmoser/Projects/puzzle/ansible-puzzle/ansible.cfg) = 20
DEFAULT_GATHERING(/home/rmoser/Projects/puzzle/ansible-puzzle/ansible.cfg) = smart
DEFAULT_HOST_LIST(/home/rmoser/Projects/puzzle/ansible-puzzle/ansible.cfg) = [u'/home/rmoser/Projects/puzzle/ansible-puzzle/inventories/cloud_staging']
DEFAULT_LOAD_CALLBACK_PLUGINS(/home/rmoser/Projects/puzzle/ansible-puzzle/ansible.cfg) = False
DEFAULT_MANAGED_STR(/home/rmoser/Projects/puzzle/ansible-puzzle/ansible.cfg) = Warning: File is managed by Ansible
DEFAULT_PRIVATE_KEY_FILE(/home/rmoser/Projects/puzzle/ansible-puzzle/ansible.cfg) = /home/rmoser/.ssh/id_rsa
DEFAULT_REMOTE_USER(/home/rmoser/Projects/puzzle/ansible-puzzle/ansible.cfg) = ansible
DEFAULT_ROLES_PATH(/home/rmoser/Projects/puzzle/ansible-puzzle/ansible.cfg) = [u'/home/rmoser/Projects/puzzle/ansible-puzzle/roles_galaxy', u'/home/rmoser/Projects/puzzle/ansible-puzzle/roles']
DEFAULT_STDOUT_CALLBACK(/home/rmoser/Projects/puzzle/ansible-puzzle/ansible.cfg) = yaml
HOST_KEY_CHECKING(/home/rmoser/Projects/puzzle/ansible-puzzle/ansible.cfg) = True
INTERPRETER_PYTHON(/home/rmoser/Projects/puzzle/ansible-puzzle/ansible.cfg) = auto
RETRY_FILES_ENABLED(/home/rmoser/Projects/puzzle/ansible-puzzle/ansible.cfg) = False

OS / ENVIRONMENT

STEPS TO REPRODUCE

---
- hosts: my.example.com
  gather_facts: yes
  tasks:
  - name: make something
    delegate_facts: True
    delegate_to: other.example.com
    lineinfile:
      path: /tmp/foo.txt
      regexp: '^Listen '
      insertafter: '^#Listen '
      line: Listen 8080

EXPECTED RESULTS

ACTUAL RESULTS

The full traceback is:
Traceback (most recent call last):
  File "/home/rmoser/Projects/resmo/ansible/lib/ansible/executor/task_executor.py", line 146, in run
    res = self._execute()
  File "/home/rmoser/Projects/resmo/ansible/lib/ansible/executor/task_executor.py", line 654, in _execute
    result = self._handler.run(task_vars=variables)
  File "/home/rmoser/Projects/resmo/ansible/lib/ansible/plugins/action/normal.py", line 46, in run
    result = merge_hash(result, self._execute_module(task_vars=task_vars, wrap_async=wrap_async))
  File "/home/rmoser/Projects/resmo/ansible/lib/ansible/plugins/action/__init__.py", line 831, in _execute_module
    (module_style, shebang, module_data, module_path) = self._configure_module(module_name=module_name, module_args=module_args, task_vars=task_vars)
  File "/home/rmoser/Projects/resmo/ansible/lib/ansible/plugins/action/__init__.py", line 244, in _configure_module
    return (module_style, module_shebang, module_data, module_path)
UnboundLocalError: local variable 'module_style' referenced before assignment
fatal: [server.example.com]: FAILED! => 
  msg: Unexpected failure during module execution.
  stdout: ''

[mkrizek]

I couldn't reproduce this with an arbitrary lineinfile task. We'll need you to provide a minimal reproducer.

[resmo]

@mkrizek I added a reproducer. It seems related to delegate_facts=true

[mkrizek]

Sounds like this might be related to #69604.

cc @bcoca

[srgvg]

Can confirm, we have the same problem, though it only triggers in particular case (localhost -> localhost)

Playbook:

# this might seem as a complex construct for just runnig setup/facts gathering on the `all` group,                        
# but this way, we are sure to have all the facts of all the hosts even if the play was run on a `--limit`ed set of hosts!
- name: Setup facts
  hosts: localhost
  tasks:
  ┊ - name: Gather facts from hosts
  ┊ ┊ setup:
  ┊ ┊ ┊ gather_subset: "all"
  ┊ ┊ delegate_to: "{{ item }}"
  ┊ ┊ delegate_facts: True
  ┊ ┊ with_items: "{{ groups['all'] }}"
  tags:
  ┊ - always

Results:

[mkrizek]

Since we now pass use_vars instead of task_vars to modify_module, we need to update information in use_vars for the next iteration too. The following makes the problem go away:

diff --git a/lib/ansible/plugins/action/__init__.py b/lib/ansible/plugins/action/__init__.py
index 83c7715d3e..62a185a3fd 100644
--- a/lib/ansible/plugins/action/__init__.py
+++ b/lib/ansible/plugins/action/__init__.py
@@ -249,7 +249,9 @@ class ActionBase(with_metaclass(ABCMeta, object)):
                     # store in local task_vars facts collection for the retry and any other usages in this worker
                     if use_vars.get('ansible_facts') is None:
                         task_vars['ansible_facts'] = {}
+                        use_vars['ansible_facts'] = {}
                     task_vars['ansible_facts'][discovered_key] = self._discovered_interpreter
+                    use_vars['ansible_facts'][discovered_key] = self._discovered_interpreter
                     # preserve this so _execute_module can propagate back to controller as a fact
                     self._discovered_interpreter_key = discovered_key
                 else:

The similar would need to be changed in the else branch as well. I am not sure if changing task_vars is needed though, or if changing all occurrences of task_vars to use_vars would be the fix.

[samdoran]

Reopening since the fix for this was reverted in #70272.

[gfidente]

as per IRC chat in #ansible-devel :

@mkrizek iirc the issue was related to using delegate_to AND delegate_facts AND ansible_python_interpreter not being explicitly set (set set to auto)

that explains why it's seen in ceph-ansible ci but we aren't seeing it in tripleo ci; in tripleo we forcibly set ansible_python_interpreter [1]

1. https://github.com/openstack/tripleo-heat-templates/blob/stable/train/common/deploy-steps.j2#L1091