Add support for F# Async<'T> as an awaitable type in minimal APIs

[brianrourkeboll]

Fixes #46773.

• Add support for F# Async<'T> as an awaitable type in minimal APIs endpoints using the same CoercedAwaitableInfo helper that is used to provide such support for controller action methods.
• Remove extra boxing/unboxing from the ObjectMethodExecutorFSharpSupport implementation so that it can be used both for the existing controller action method scenario as well as for the minimal APIs endpoint scenario.
• Add request delegate factory tests for F# Async<'T> wherever there were existing tests for Task<TResult> or ValueTask<TResult>.
• Update the existing F# async coercion to turn Async<unit>¹ into void-returning (non-generic) Task instead of Task<unit>.
• Add conversion of Task<unit> to Task and ValueTask<unit> to ValueTask.
• Add tests showing that the above conversions are supported for runtime request delegate creation but not by the compile-time source generator.

Footnotes

1. https://learn.microsoft.com/en-us/dotnet/fsharp/language-reference/unit-type ↩

[ghost]

Thanks for your PR, @brianrourkeboll. Someone from the team will get assigned to your PR shortly and we'll get it reviewed.

[brianrourkeboll]

@dotnet-policy-service agree

[ghost]

Looks like this PR hasn't been active for some time and the codebase could have been changed in the meantime.
To make sure no breaking changes are introduced, please leave an /azp run comment here to rerun the CI pipeline and confirm success before merging the change.

[brianrourkeboll]

/azp run

[azure-pipelines]

Commenter does not have sufficient privileges for PR 46898 in repo dotnet/aspnetcore

[captainsafia]

There are also references to the AwaitableInfo API in the OpenAPI-related codepaths we have in OpenApiGenerator and EndpointMetadataApiDescription provider. Can we update those too for consistency across the different places?

[brianrourkeboll]

@captainsafia @halter73 when trying to bring this branch up to date with main, it was not immediately obvious to me how best to make the changes in this PR work with the new, shared request delegate creation tests: while the runtime creation invocations pass in brianrourkeboll@13e9f30, the compile-time ones do not (as expected).

I think there are two options:

1. I can split out the F# coercion tests and make them runtime-only (but I don't fully know what your plans are for RequestDelegateFactoryTests migration #47345 and how that might interact with them).
2. I can just add compile-time coercion support along the lines of brianrourkeboll@413a22c. Though it is admittedly unlikely to see frequent use, it is relatively straightforward and noninvasive.

Do you have a preference?

[mitchdenny]

It probably makes sense to make them runtime only.

[brianrourkeboll]

All right, I added the runtime tests back to RequestDelegateFactoryTests.cs in 2111eb2. If there's a better place for me to put them, or if you'd rather I took out the (now-redundant) Task/ValueTask parts, let me know.

[brianrourkeboll]

Let me know if there's anything else you need from me on this.

[captainsafia]

/azp run

[azure-pipelines]

Azure Pipelines successfully started running 3 pipeline(s).

[ghost]

Looks like this PR hasn't been active for some time and the codebase could have been changed in the meantime.
To make sure no conflicting changes have occurred, please rerun validation before merging. You can do this by leaving an /azp run comment here (requires commit rights), or by simply closing and reopening.

[captainsafia]

/azp run

[captainsafia]

I'll admit to having limited knowledge on the F# front here but the implementation seems sensible and doesn't introduce any breaking changes.

[azure-pipelines]

Pipelines were unable to run due to time out waiting for the pull request to finish merging.

[brianrourkeboll]

Thanks, @captainsafia!

[ghost]

Hi @brianrourkeboll. It looks like you just commented on a closed PR. The team will most probably miss it. If you'd like to bring something important up to their attention, consider filing a new issue and add enough details to build context.