catchToEffect deprecation without alternative for supported platform

[jaredh159]

huge fan of TCA and your work. thanks so much for all your libraries. 🙏

currently working with the prerelease/1.0 branch, building a macOS app that targets 10.15 - 13. 10.15 (Catalina) is a supported platform according to the Package.swift.

but, I'm getting deprecation warnings trying to use .catchToEffect, with a suggestion that I iterate over publisher.values. that's all well and good, but publisher.values isn't available until macOS 12. so, i can't convert to it.

can this warning/deprecation be scoped to platforms that support the alternative? or is there some alternative I'm not aware of that would work without deprecation/warning as far back as 10.15?

and I'm hoping you aren't planning on removing this api soon, right? unless I'm missing something that would force a platform compat bump all the way to macos 12.

apologies if there's something obvious i'm overlooking here.

[stephencelis]

Hi @jaredh159! Not sure if you've pulled recently, but last week we added to the deprecation message to also suggest using Effect.publisher, which acts as a Combine bridge for earlier for older platforms:

swift-composable-architecture/Sources/ComposableArchitecture/Effects/Publisher.swift

Line 383 in 132cb3b

"Iterate over 'Publisher.values' in an 'EffectTask.run', instead, or use 'EffectTask.publisher'."

You can then use Publisher.catch and other Combine operations on the publisher in that block:

return .publisher {
  self.dependencyThatCanFail()
    .map { .response(.success($0)) }
    .catch { .response(.failure($0)) }
}

I'm going to convert this to a discussion since I think it's more of a question than a bug.

[jaredh159]

@acosmicflamingo thanks, that was the tip i needed, a quick rm -rf .build/ and then swift package update worked like a charm. shoulda guessed that.

[Alex293]

if you use Xcode you can also use file -> spm -> reset cache to get the same behaviour

[tlandsman]

I'm still confused. Can you give an example of how to use EffectTask.run' or EffectTask.publisher replaces catchToEffect?

[jaredh159]

@tlandsman the example Stephen posted is basically what I ended up doing, stuff like:

return .publisher {
  self.dependencyThatCanFail()
    .map { .response(.success($0)) }
    .catch { .response(.failure($0)) }
}

or, in my case, something like:

return .publisher {
  websocket.receive()
    .map { .websocket(.receivedMessage($0)) }
    .receive(on: mainQueue)
}

[tlandsman]

Thanks! Much appreciated.