We're occasionally seeing stacktraces like this in our tests:
Fatal Python error: Cannot recover from stack overflow.
Current thread 0x00007fe66549f740 (most recent call first):
File "...nova/.tox/py36/lib/python3.6/site-packages/oslo_config/cfg.py", line 2614 in _get
File "...nova/.tox/py36/lib/python3.6/site-packages/oslo_config/cfg.py", line 2183 in __getattr__
File "...nova/.tox/py36/lib/python3.6/site-packages/oslo_config/cfg.py", line 2614 in _get
File "...nova/.tox/py36/lib/python3.6/site-packages/oslo_config/cfg.py", line 2183 in __getattr__
File "...nova/.tox/py36/lib/python3.6/site-packages/oslo_config/cfg.py", line 2614 in _get
...
From a look at the oslo.config source, this seems to be occurring
because 'ConfigOpts.__cache' is somehow undefined, which results in the
'_get' method attempting to call '__getattr__' [1], which calls '_get'
[2], which calls '__getattr__' and so on.
The exact reason this is happening isn't clear, but what is clear is
that how we handle global config options in the tests that are failing
is very strange and potentially subject to race conditions. We have a
clear pattern for mocking everything and anything - the mock module -
and we should be using this here. Start doing so, reworking a lot of the
tests in the process, in order to avoid messing with oslo.config and
triggering the issue entirely.
[1] https://github.com/openstack/oslo.config/blob/6.8.1/oslo_config/cfg.py#L2614
[2] https://github.com/openstack/oslo.config/blob/6.8.1/oslo_config/cfg.py#L2183
Change-Id: I468cef94185a1b59f379ca527050450e03664c67
Signed-off-by: Stephen Finucane <sfinucan@redhat.com>
Closes-Bug: #1825435
1a4a521fef