RequiresThreadAttribute allows ApartmentState.Unknown, unlike ApartmentAttribute

[jnm2]

Does it make sense to allow [RequiresThread(ApartmentState.Unknown)]?

[ChrisMaddock]

I guess it makes sense if #3041 is differentiating between MTA and 'UnInitialized' - and in which case is should be 'Uninitialized' instead?

These are hierachical, right? Presumably I would want this if I wanted to make an entire assembly as STA, and then certain fixtures as 'not-STA'?

Is there a cost to permitting it? Other than the face I don't like the "Unknown" name? 😄

[CharliePoole]

Note that in older versions of .NET ApartmentState.Unknown meant "not yet set." If you did nothing, the apartment used was MTA.

[jnm2]

I left out part of the question, sorry. Given that [RequiresThread] is always allowed, should [RequiresThread(ApartmentState.Unknown)] also be allowed? If so, should we allow [Apartment(ApartmentState.Unknown)]?

We can't change Unknown to Uninitialized unless we declare our own enum. :D

@CharliePoole I can't think of any use cases for running tests that care about the apartment state and need it to be uninitialized. The only reason it's worth differentiating between leaving COM uninitialized and setting it to MTA is just so we can error in one case and not the other on platforms other than Windows.

(Edit: as I've recently learned, there is no such thing as leaving COM uninitialized on .NET threads on Windows. It'll be MTA or STA.)

[ChrisMaddock]

I understand, sorry. Yes - I agree these two attributes should be consistent.

This is a good issue for first-time contributors! To anyone interested:

• Take a look at the existing check in ApartmentAttribute:
  

  nunit/src/NUnitFramework/framework/Attributes/ApartmentAttribute.cs

  Line 44 in 5163de6

  Guard.ArgumentValid(apartmentState != ApartmentState.Unknown, "must be STA or MTA", nameof(apartmentState));

To close this issue, we should introduce a similar check in RequiresThreadAttribute. And of course, a unit test to support the behaviour!

[petmat]

I'll take a look at this if it's ok!

[jnm2]

Great, let us know if you need anything!