View dependend protocols should be marked with @MainActor

[BastianKusserow]

(Required) Version Number: 8.0.5

Description

I've got a ViewController that conforms to the JTACMonthViewDelegate protocol. With strict concurrency warnings turned on, the compiler complains that "Main-actor isolated instance method cannot be used to satisfy nonisolated protocol requirement` since the ViewController is obviously marked @mainactor. I think all the view dependent delegate protocols (and probably also the data source protocols) should be marked @mainactor, since they are probably called from the main actor anyways. This is also how UICollectionViewDelegate and DataSources are marked.

Steps To Reproduce

Conform a ViewController to a delegate like JTACMonthViewDelegate with swift strict concurrency warnings set to complete.

Expected Behavior

The compiler shouldn't complain about nonisolated protocol requirements.

[patchthecode]

hmmm...
if i put mainactorinto this library, i think this will raise the minimum OS requirement?
if yes, then is there another way around this? I am unfamiliar with mainactor

[BastianKusserow]

Hmh, might work if we gate this with #if swift(<5.4) or something like that. I can try this out and submit a PR if you want to.