Example doesn't compile with default MainActor isolation

[mergesort]

Hey @mattt, thanks so much for this great library! It really solves a problem that I've had across a few of my apps, and the API is terrific.

I was excited to try out the library but ran into an issue pretty quickly with a brand new project. The example Weather Tool doesn't compile in a new Xcode project that has Main Actor set for it's default isolation.

import AnyLanguageModel

struct WeatherTool: Tool {
    let name = "getWeather"
    let description = "Retrieve the latest weather information for a city"

    @Generable
    struct Arguments {
        @Guide(description: "The city to fetch the weather for")
        var city: String
    }

    func call(arguments: Arguments) async throws -> String {
        "The weather in \(arguments.city) is sunny and 72°F / 23°C"
    }
}

It's pretty easy to reproduce, all you have to do is paste that into a fresh Xcode project you'll undoubtedly run into this error.

Main actor-isolated conformance of 'WeatherTool.Arguments' to 'ConvertibleToGeneratedContent' cannot satisfy conformance requirement for a 'Sendable' type parameter 'Self'

I'm actually not sure the best way to handle this in a way that's meant to be compatible with AnyLanguageModel. I can of course switch the project to nonisolated for the default actor isolation, but that's not a real long-term fix so I figured it was worth mentioning, to be addressed at the library-level (or with some guidance for how to best handle this).

Would appreciate your thoughts, and thanks again for great work!

[mattt]

Thank you for reporting this, @mergesort. I just merged #26 which I believe should resolve this issue. This is now available in 0.3.3.

I tried validating locally on Sequoia / Xcode 16.4, but got into a bad state with caching / networking issues during package resolution. I'm away from my primary machine today, but can give this a try tomorrow. In the meantime, feel free to give this a try yourself and let me know if it's working as expected.

[mergesort]

I tested it just now and it's still not quite working when I turn on MainActor isolation. (Pinned to 0.4.0)

Xcode adds this macro expansion.

And the underlying error message is this.

Main actor-isolated conformance of 'WeatherTool.Arguments' to 'ConvertibleToGeneratedContent' cannot satisfy conformance requirement for a 'Sendable' type parameter 'Self'

- In expansion of macro 'Generable' on struct 'Arguments' here
- Requirement specified as 'Self' : 'ConvertibleToGeneratedContent' [with Self = WeatherTool.Arguments]
- In expansion of macro 'Generable' on struct 'Arguments' here

- Type 'WeatherTool.Arguments' does not conform to protocol 'Generable'
  - In expansion of macro 'Generable' on struct 'Arguments' here

Hope this is helpful, and no rush of course in getting back to your computer!

[purkylin]

You seem missed isolated keyword for the extension statement.
Add this will fix it:

InheritedTypeSyntax(type: TypeSyntax(stringLiteral: "nonisolated")),

The Generable macro should also add default init method.

[mattt]

Thanks for following up, @mergesort and @purkylin. Reopening until we have a confirmed fix.

I just opened #28 with another attempt to resolve. When you have a chance, @mergesort, can you please try depending on the mattt/fix-generable branch and let me know if that works for you?

[mergesort]

The branch worked great, should be shippable as far as I can tell!

[mattt]

@mergesort Awesome! So glad to hear it! Thank you for verifying the fix.

This is now in 0.4.1.