1.5.0rc2: callback failing to save results for a particular set of playbooks with 'NoneType' object is not subscriptable

[dmsimard]

What is the issue ?

When running ansible-playbook with ara enabled, the callback can succeed in creating the playbook (no errors about v2_playbook_on_playbook_start) but then fail on other methods:

 [WARNING]: Failure using method (v2_playbook_on_play_start) in callback plugin
(<ansible.plugins.callback.ara_default.CallbackModule object at
0x7fe83d039be0>): 'ascii' codec can't decode byte 0xc2 in position 626: ordinal
not in range(128)
[WARNING]: Failure using method (v2_playbook_on_task_start) in callback plugin
(<ansible.plugins.callback.ara_default.CallbackModule object at
0x7fe83d039be0>): 'NoneType' object is not subscriptable
 [WARNING]: Failure using method (v2_runner_on_unreachable) in callback plugin
(<ansible.plugins.callback.ara_default.CallbackModule object at
0x7fe83d039be0>): 'NoneType' object is not subscriptable
[WARNING]: Failure using method (v2_runner_on_ok) in callback plugin
(<ansible.plugins.callback.ara_default.CallbackModule object at
0x7fe83d039be0>): 'NoneType' object is not subscriptable
 [WARNING]: Failure using method (v2_runner_on_skipped) in callback plugin
(<ansible.plugins.callback.ara_default.CallbackModule object at
0x7fe83d039be0>): 'NoneType' object is not subscriptable

I haven't yet narrowed down the root cause but it repeats consistently for a particular set of playbooks and haven't seen it reproduce elsewhere. It looks like the creation of the play fails due to an encoding (or decoding) error and then it cascades to the other methods because they try to associate themselves to a play that doesn't exist.

What should be happening ?

It shouldn't fail :)