2.x variable return value fix

[Samreay]

Checklist

• [x] This pull request references https://github.com/PrefectHQ/prefect/issues/15061

[desertaxle]

Thanks for the PR @Samreay! It looks like the tests didn't run for some reason. I suspect some of the tests in tests/test_variables.py will need to be updated. Could you update those tests to make sure they pass (and if they do, push another commit to try and get CI to run)?

[cicdw]

Variable tests appear to be failing which makes me think there's something I'm missing here 🧐

[Samreay]

@cicdw this is a fun one. There's the class in prefect.variables.Variables and I was assuming that the get method when using Variable.get would return an instance of that class. It doesn't - it returns an instance of prefect.client.schemas.objects.Variable, and so the isinstance check is failing.

I suppose this means my type hints are technically wrong, but still functional due to duck typing.

I'll swap the code to doing a string check and hasattr so Im not importing a second Variable class and making life hell for people down the road trying to figure out which class they want. (I dont understand the different between the two - is one just used for a serialisation layer?)

[cicdw]

@Samreay wow that's rough, I'm sorry about that! Yea the schema object is just serialization layer, so I think you can update get to return a class instance of prefect.variables.Variable, the schema objects really don't need to be exposed directly to users

[Samreay]

@cicdw I have now updated the get method so that it returns the expected class. Hopefully this all looks good now :)