Incorrect types in for `Invocation.action`

[julianstirling]

Describe the bug
In the OpenFlexure microscope server we use the ActionManager of the server to determine the calling action for an invocation when recording log information. We get the invocation with get_invocation(). Using this Invocation object we can do invocation.action.name to get the action name. But MyPy throws and error unless you call invocation.action().name; this makes MyPy happy but throws an error at runtime. The issues seems to be because the action is a descriptor.

To get around this we directly invocation.action_ref().name which even though there is no leading underscore feels like accessing an internal.

To Reproduce

• On an Invocation object add the line invocation.action.name
• Run MyPy

Expected behaviour

MyPy passes as the code is fine

Actual behaviour

MyPy throws and error unless you do invocation.action().name. This errors at runtime.

System:

• OS: Kuuntu 24.04 (verified also on docker image python:3.11)
• Python version: 3.11
• Version: 0.3.0

[rwb27]

Sadly I've not found a way around this. The 'Invocation.actionproperty is correctly typed as returning anActionDescriptorbutmypyinfers the return type of the descriptor. I believe this is indirect behaviour inmypy` and I should probably raise an issue. They should probably tell me that a property returning a descriptor instance is evil and confusing.

I use the same work around in places, the weak ref stops mypy getting confused.

I would like to use an ActionInfo object instead. This is intended as a much nicer way to refer to an action without passing around descriptors.