[release/8.0] Add explicit conversion for value-type returning handlers with filters

[captainsafia]

Description

Merged in 10.0: #57428
Addresses #52128.

This PR fixes a bug with the handling of value type-returning handlers that are used in conjunction with endpoint filters. Such as:

var app = WebApplication.Create();

app
	.MapGet("/", () => { return 1; })
	.AddEndpointFilter(async (context, next) => await next(context));

app.Run();

This currently throws:

ArgumentException: Expression of type 'System.Int32' cannot be used for parameter of type 'System.Object' of method 'System.Threading.Tasks.ValueTask`1[System.Object] WrapObjectAsValueTask(System.Object)' (Parameter 'arg0')

Because the return type requires an explicit conversion before being wrapped as a ValueTask<object> to confirm with the EndpointFilterDelegate's signature.

Customer Impact

Without this bug fix, user applications that contain minimal API endpoints that return value types and use endpoint filters will fail to launch. Viable workarounds exist (for example, wrapping the value return in a Results.Ok), but they are difficult for the typical user to discover.

Regression?

• Yes
• No

Risk

• High
• Medium
• Low

Scope of impact is limited to minimal APIs + endpoint filters + compile-time code generation.

Verification

• Manual (required)
• Automated

Packaging changes reviewed?

• Yes
• No
• N/A

[BrennanConroy]

Does RDG handle this? I did a quick search and wasn't able to find any tests that cover it for RDG

[captainsafia]

Does RDG handle this? I did a quick search and wasn't able to find any tests that cover it for RDG

RDG doesn't have this problem because the compiler will do the conversion implicitly when a value type is passed into the this method.

As for tests, I don't believe we have test coverage for this scenario in RDG but I can add one (or move the tests that we have here to the shared infrastructure).

[captainsafia]

Approved via email.