AttributeError: 'module' object has no attribute 'ActionBase'

[mkhon]

I am using mitogen from tag v0.2.10 (which is identical to 0.2-release HEAD)

$ ansible --version      
/usr/local/lib/python2.7/dist-packages/ansible/parsing/vault/__init__.py:44: CryptographyDeprecationWarning: Python 2 is no longer supported by the Python core team. Support for it is now deprecated in cryptography, and will be removed in the next release.
  from cryptography.exceptions import InvalidSignature
ansible 2.9.27
  config file = /home/spdev_svc_sdpss_jenkinsbuild/workspace/Surfbeam_2_Jenkins/SDP-SS/DHCP_FR_CI_PIPELINE/dhcp_fr_deploy_ci/ansible.cfg
  configured module search path = [u'/home/spdev_svc_sdpss_jenkinsbuild/.ansible/plugins/modules', u'/usr/share/ansible/plugins/modules']
  ansible python module location = /usr/local/lib/python2.7/dist-packages/ansible
  executable location = /usr/local/bin/ansible
  python version = 2.7.18 (default, Mar  8 2021, 13:02:45) [GCC 9.3.0]

$ lsb_release -a
No LSB modules are available.
Distributor ID:	Ubuntu
Description:	Ubuntu 20.04.4 LTS
Release:	20.04
Codename:	focal

Playbooks no longer run:

PLAY [all] ***************************************************************************************************
ERROR! Unexpected Exception, this is probably a bug: 'module' object has no attribute 'ActionBase'
the full traceback was:

Traceback (most recent call last):
  File "/usr/local/bin/ansible-playbook", line 123, in <module>
    exit_code = cli.run()
  File "/usr/local/lib/python2.7/dist-packages/ansible/cli/playbook.py", line 128, in run
    results = pbex.run()
  File "/usr/local/lib/python2.7/dist-packages/ansible/executor/playbook_executor.py", line 169, in run
    result = self._tqm.run(play=play)
  File "/usr/local/lib/python2.7/dist-packages/ansible/executor/task_queue_manager.py", line 261, in run
    strategy = strategy_loader.get(new_play.strategy, self)
  File "/usr/local/lib/python2.7/dist-packages/ansible/plugins/loader.py", line 552, in get
    self._module_cache[path] = self._load_module_source(name, path)
  File "/usr/local/lib/python2.7/dist-packages/ansible/plugins/loader.py", line 530, in _load_module_source
    module = imp.load_source(to_native(full_name), to_native(path), module_file)
  File "/home/spdev_svc_sdpss_jenkinsbuild/workspace/Surfbeam_2_Jenkins/SDP-SS/DHCP_FR_CI_PIPELINE/dhcp_fr_deploy_ci/mitogen/ansible_mitogen/plugins/strategy/mitogen_linear.py", line 56, in <module>
    import ansible_mitogen.strategy
  File "/home/spdev_svc_sdpss_jenkinsbuild/workspace/Surfbeam_2_Jenkins/SDP-SS/DHCP_FR_CI_PIPELINE/dhcp_fr_deploy_ci/mitogen/ansible_mitogen/strategy.py", line 43, in <module>
    import ansible_mitogen.mixins
  File "/home/spdev_svc_sdpss_jenkinsbuild/workspace/Surfbeam_2_Jenkins/SDP-SS/DHCP_FR_CI_PIPELINE/dhcp_fr_deploy_ci/mitogen/ansible_mitogen/mixins.py", line 78, in <module>
    class ActionModuleMixin(ansible.plugins.action.ActionBase):
AttributeError: 'module' object has no attribute 'ActionBase'

If I change the import in mitogen/ansible_mitogen/mixins.py as follows everything works as expected:

diff --git a/ansible_mitogen/mixins.py b/ansible_mitogen/mixins.py
index 7672618d..a21289a3 100644
--- a/ansible_mitogen/mixins.py
+++ b/ansible_mitogen/mixins.py
@@ -44,7 +44,7 @@ from ansible.parsing.utils.jsonify import jsonify
 import ansible
 import ansible.constants
 import ansible.plugins
-import ansible.plugins.action
+from ansible.plugins.action import ActionBase
 
 import mitogen.core
 import mitogen.select
@@ -75,7 +75,7 @@ except ImportError:
 LOG = logging.getLogger(__name__)
 
 
-class ActionModuleMixin(ansible.plugins.action.ActionBase):
+class ActionModuleMixin(ActionBase):
     """
     The Mitogen-patched PluginLoader dynamically mixes this into every action
     class that Ansible attempts to load. It exists to override all the